Regulation UN No. 117 (Rev.4)

Tyres rolling resistance, rolling noise and wet grip

Consolidated up to Suppl.10 to 02 dated: 11.01.20

... 1. Scope a0c0
... 2. Definitions a0c0
... 3. Application for approval a0c0
... 4. Markings a0c0
... 5. Approval a0c0
... 6. Specifications a0c0
... 7. Modifications of the type of pneumatic tyre and extension of approval a0c0
... 8. Conformity of production a0c0
... 9. Penalties for non-conformity of production a0c0
... 10. Production definitively discontinued a0c0
... 11. Names and addresses of Technical Services responsible for conducting approval tests of Type Approval Authorities a0c0
... 12. Transitional provisions a0c0
... Annexes a0c0
... 1. Communication a0c0
... 2. a0c0
... Appendix 1 - Example of approval marks a0c0
... Appendix 2 - Example of the arrangement of the approval mark a0c0
... Appendix 3 - Approval according to Regulation No. 117 coincident with approval of Regulation No. 30 or 54 a0c0
... Appendix 4 - Extensions to combine approvals issued in accordance with Regulation No. 117 a0c0
... 3. Coast-by test method for measuring tyre-rolling sound emission a0c0
... Appendix 1 - Test report a0c0
... 4. Specifications for the test site a0c0
... 5. Test procedures for measuring wet grip a0c0
... Appendix 1 - Test reports examples of wet grip index a0c0
... 6. Test procedure for measuring rolling resistance a0c0
... Appendix 1 -Test equipment tolerances a0c0
... Appendix 2 - Measuring rim width a0c0
... Appendix 3 - Test report and test data (Rolling resistance) a0c0
... Appendix 4 -Tyre standards organizations a0c0
... Appendix 5 - Deceleration method: Measurements and data processing for deceleration value obtaining in differential form dω/dt a0c0
... 7. Procedures for snow performance testing relative to snow tyre for use in severe snow conditions a0c0
... Pictogram definition of "Alpine Symbol" a0c0
... Appendix 2 - Test reports and test data for C1 and C2 tyres a0c0
... Appendix 3 - Test reports and test data for C3 tyres a0c0
1. SCOPE a0c0
1.1. This Regulation applies to new pneumatic tyres[*] of Classes C1, C2 and C3 with regard to their sound emissions, rolling resistance and to adhesion performance on wet surfaces (wet adhesion). It does not, however, apply to: a1c0
[*] For the purpose of this Regulation "tyres" means "pneumatic tyres" a1c0
1.1.1. Tyres designed as "Temporary use spare tyres" and marked "Temporary use only"; a0c0
1.1.2. Tyres having a nominal rim diameter code ≤ 10 (or ≤ 254 mm) or ≥ 25 (or ≥ 635 mm); a0c0
1.1.3. Tyres designed for competitions; a0c0
1.1.4. Tyres intended to be fitted to road vehicles of categories other than M, N and O;[1] a0c0
1.1.5. Tyres fitted with additional devices to improve traction properties (e.g. studded tyres); a0c0
1.1.6. Tyres with a speed rating less than 80 km/h (speed symbol F); a0c0
1.1.7. Tyres designed only to be fitted to vehicles registered for the first time before 1 October 1990. a0c0
1.1.8. Professional off-road tyres. a0c0
1.2. Contracting Parties shall issue or accept approvals to rolling sound and/or wet adhesion and/or rolling resistance. a0c0
[1] As defined in the Consolidated Resolution on the Construction of Vehicles (R.E.3), document ECE/TRANS/WP.29/78/Rev.4, para. 2. - www.unece.org/trans/main/wp29/wp29wgs/wp29gen/wp29resolutions.html a0c0
2. DEFINITIONS a0c0
... For the purpose of this Regulation, in addition to the definitions contained in Regulations Nos. 30 and 54, the following definitions apply. a0c0
2.1. "Type of tyre" means tyres which do not differ in such essential characteristics as: a2c0
... (a) The manufacturer's name; a0c0
... (b) The tyre class (see paragraph 2.4. below); a0c0
... (c) The tyre structure; a0c0
... (d) The category of use: normal tyre, snow tyre and special use tyre; a0c0
... (e) For Class C1 tyres: a0c0
... (i) In case of tyres submitted for approval of rolling sound emission levels, whether normal or reinforced (or extra load); a0c0
... (ii) In case of tyres submitted for approval of performance adhesion on wet surfaces, whether normal tyres or snow tyres with a speed category of Q or below excluding H (≤ 160 km/h) or speed category R and above including H (> 160 km/h); a0c0
... (f) For Classes C2 and C3 tyres: a0c0
... (i) In case of tyres submitted for approval of rolling sound emission levels at stage 1, whether M+S marked or not; a0c0
... (ii) In case of tyres submitted for approval of rolling sound emission levels at stage 2, whether traction tyre or not; a0c0
... (g) The tread pattern (see paragraph 3.2.1. of this Regulation). a0c0
2.2. "Manufacturer" means the person or body who is responsible to the Type Approval Authority (TAA) for all aspects of the type-approval and for ensuring the conformity of production." a1c0
2.3. Brand name/trademark" means the identification of the brand or trademark as defined by the tyre manufacturer and marked on the sidewall(s) of the tyre. The Brand name/trademark may be the same as that of the Manufacturer. a1c0
2.4. Trade description/commercial name: means an identification of a range of tyres as given by the tyre manufacturer. It may coincide with the brand name/trademark. a1c0
2.5. "Rolling sound emission" means the sound emitted from the contact between the tyres in motion and the road surface. a1c0
2.6. "Tyre class" means one of the following groupings: a1c0
2.6.1. Class C1 tyres: Tyres conforming to Regulation No. 30; a1c0
2.6.2. Class C2 tyres: Tyres conforming to Regulation No. 54 and identified by a load capacity index in single formation lower or equal to 121 and a speed category symbol higher or equal to "N"; a1c0
2.6.3. Class C3 tyres: Tyres conforming to Regulation No. 54 and identified by: a1c0
... (a) A load capacity index in single formation higher or equal to 122; or a0c0
... (b) A load capacity index in single formation lower or equal to 121 and a speed category symbol lower or equal to "M". a0c0
2.7. "Representative tyre size" means the tyre size which is submitted to the test described in Annex 3 to this Regulation with regard to rolling sound emissions, or Annex 5 for adhesion on wet surfaces or Annex 6 for rolling resistance to assess the conformity for the type approval of the type of tyre, or Annex 7 for use in severe snow conditions. a1c0
2.8. "Temporary-use spare tyre" means a tyre different from a tyre intended to be fitted to any vehicle for normal driving conditions; but intended only for temporary use under restricted driving conditions. a1c0
2.9. "Tyres designed for competition" means tyres intended to be fitted to vehicles involved in motor sport competition and not intended for non-competitive on-road use. a1c0
2.10. "Normal tyre" means a tyre intended for normal on-road use. a1c0
2.11. "Reinforced tyre" or "extra load tyre" of Class C1 means a DELtyre structure designed to carry more load at a higher inflation pressure than the load carried by the corresponding standard version tyre at the standard inflation pressure as specified in ISO 4000-1:2010.[2] a1c0
[2] Class C1 tyres correspond to "passenger car tyres" in ISO 4000-1:2010. a0c0
2.12. "Traction tyre" means a tyre in Class C2 or C3 bearing the inscription TRACTION and intended to be fitted primarily to the drive axle(s) of a vehicle to maximize force transmission in various circumstances. a1c0
2.13. "Snow tyre" means a tyre whose tread pattern, tread compound or structure is primarily designed to achieve in snow conditions a performance better than that of a normal tyre with regard to its ability to initiate or maintain vehicle motion. a1c0
2.13.1. "Snow tyre for use in severe snow conditions" means a snow tyre whose tread pattern, tread compound or structure is specifically designed to be used in severe snow conditions and that fulfils the requirements of paragraph 6.4. of this Regulation. a1c0
2.14. "Special use tyre" means a tyre intended for mixed use both on- and off-road or for other special duty. These tyres are primarily designed to initiate and maintain the vehicle in motion in off-road conditions. a1c0
2.15. "Professional off-road tyre" is a special use tyre primarily used for service in severe off-road conditions. a1c0
2.16. "Tread depth" means the depth of the principal grooves. a1c0
2.16.1. "Principal grooves" means the wide circumferential grooves positioned in the central zone of the tyre tread, which, in the case of passenger and light truck (commercial) tyres, have the treadwear indicators located in the base. a1c0
2.17. "Void to fill ratio" means the ratio between the area of voids in a reference surface and the area of this reference surface calculated from the mould drawing. a1c0
2.18. "Standard Reference Test Tyre (SRTT)" means a tyre that is produced, controlled and stored in accordance with the American Society for Testing and Materials (ASTM) standards a1c0
... (a) E1136-93 (2003) for the size P195/75R14 a0c0
... (b) F2872 (2011) for the size 225/75 R 16 C a0c0
... (c) F2871 (2011) for the size 245/70R19.5 a0c0
... (d) F2870 (2011) for the size 315/70R22.5. a0c0
2.19. Wet grip or snow grip measurements - Specific definitions a1c0
2.19.1. "Adhesion on wet surfaces" means the relative braking performance, on a wet surface, of a test vehicle equipped with the candidate tyre in comparison to that of the same test vehicle equipped with a reference tyre (SRTT). a1c0
2.19.2. "Candidate tyre" means a tyre, representative of the type that is submitted for approval in accordance with this Regulation. a1c0
2.19.3. "Control tyre" means a normal production tyre that is used to establish the wet grip or snow grip performance of tyre sizes unable to be fitted to the same vehicle as the standard reference test tyre - see paragraph 4.1.7. of Annex 5 and paragraph 3.4.3. of Annex 7 to this Regulation. a1c0
2.19.4. "Wet grip index ("G")" means the ratio between the performance of the candidate tyre and the performance of the standard reference test tyre. a1c0
2.19.5. "Snow grip index ("SG")" means the ratio between the performance of the candidate tyre and the performance of the standard reference test tyre. a1c0
2.19.6. "Peak brake force coefficient ("pbfc")" means the maximum value of the ratio of braking force to vertical load on the tyre prior to wheel lock-up. a1c0
2.19.7. "Mean fully developed deceleration ("mfdd")" means the average deceleration calculated on the basis of the measured distance recorded when decelerating a vehicle between two specified speeds. a1c0
2.19.8. "Coupling (hitch) height" means the height when measured perpendicularly from the centre of the articulation point of the trailer towing coupling or hitch to the ground, when the towing vehicle and trailer are coupled together. The vehicle and trailer shall be standing on level pavement surface in its test mode complete with the appropriate tyre(s) to be used in the particular test. a1c0
2.20. Rolling resistance measurement - Specific definitions a1c0
2.20.1. Rolling resistance Fr a1c0
... Loss of energy (or energy consumed) per unit of distance traveled.[3] a0c0
[3] The International System of Units (SI) unit conventionally used for the rolling resistance is the newton-meter per meter, which is equivalent to a drag force in newton. a0c0
2.20.2. Rolling resistance coefficient Cr a1c0
... Ratio of the rolling resistance to the load on the tyre.[4] a0c0
[4] The rolling resistance is expressed in newton and the load is expressed in kilo-newton. The rolling resistance coefficient is dimensionless. a0c0
2.20.3. New test tyre a1c0
... A tyre which has not been previously used in a rolling deflected test that raises its temperature above that generated in rolling resistance tests, and which has not previously been exposed to a temperature above 40 C.[5], [6] a0c0
[5] New test tyre definition is needed to reduce potential data variation and dispersion due to tyre aging effects. a0c0
[6] It is permissible to repeat an accepted test procedure. a0c0
2.20.4. Laboratory control tyre a1c0
... Tyre used by an individual laboratory to control machine behaviour as a function of time.[7] a0c0
[7] An example of machine behaviour is drift. a0c0
2.20.5. Capped inflation a1c0
... Process of inflating the tyre and allowing the inflation pressure to build up, as the tyre is warmed up while running. a0c0
2.20.6. Parasitic loss a1c0
... Loss of energy (or energy consumed) per unit distance excluding internal tyre losses, attributable to aerodynamic loss of the different rotating elements of the test equipment, bearing friction and other sources of systematic loss which may be inherent in the measurement. a0c0
2.20.7. Skim test reading a1c0
... Type of parasitic loss measurement, in which the tyre is kept rolling without slippage, while reducing the tyre load to a level at which energy loss within the tyre itself is virtually zero. a0c0
2.20.8. Inertia or moment of inertia. a1c0
... Ratio of the torque applied to a rotating body to the rotational acceleration of this body.[8] a0c0
[8] The rotating body can be, for example, a tyre assembly or machine drum. a0c0
2.20.9. Measurement reproducibility m a1c0
... Capability of a machine to measure rolling resistance.[9] a0c0
[9] Measurement reproducibility m shall be estimated by measuring n times (where n 3), on a single tyre, the whole procedure described in paragraph 4. of Annex 6 as follows: a0c0
... a0c0
... Where: a0c0
... j = is the counter from 1 to n for the number of repetitions of each measurement for a given tyre, a0c0
... n = number of repetitions of tyre measurements (n 3). a0c0
3. Application for approval a0c0
3.1. The application for approval of a type of tyre with regard to this Regulation shall be submitted by the tyre manufacturer or by his duly accredited representative. It shall specify: a0c0
3.1.1. The performance characteristics to be assessed for the tyre type; "rolling sound emissions level" and/or "adhesion performance level on wet surfaces" and/or "rolling resistance level". Tyre "snow performance level" in cases of "snow tyre for use in severe snow conditions"; a0c0
3.1.2. Manufacturer's name; a1c0
3.1.3. Name and address of applicant; a0c0
3.1.4. Address(es) of manufacturing plant(s); a0c0
3.1.5. Brand name(s)/trademark(s), trade description(s)/commercial name(s); a1c0
3.1.6. Tyre class (Class C1, C2 or C3) (see paragraph 2.4. of this Regulation); a0c0
3.1.6.1. Section width range for Class C1 tyres (see paragraph 6.1.1. of this Regulation); a0c0
Note: This information is required only for approval with regard to rolling sound emission level. a0c0
3.1.7. Tyre structure; a0c0
3.1.8. For Class C1 tyres, state whether: a0c0
... (a) Reinforced (or extra load) in case of approval with regard to rolling sound emission level; a0c0
... (b) Speed category symbol "Q" or below (excluding "H") or "R" and above (including "H") in case of "snow" tyres for approval with regard to adhesion on wet surfaces; a0c0
... For Classes C2 and C3 tyres, state whether: a0c0
... (a) M+S marked in case of approval with regard to rolling sound emission level at stage 1; a0c0
... (b) Traction in case of approval with regard to rolling sound emission level at stage 2. a0c0
3.1.9. Category of use (normal, snow, or special); a0c0
3.1.10. A list of tyre size designations covered by this application. a0c0
3.2. The application for approval shall be accompanied (in triplicate) by: a0c0
3.2.1. Details of the major features, with respect to the effects on the performance (i.e. rolling sound emission level, adhesion on wet surfaces, rolling resistance and snow grip) of the tyres, including the tread pattern, included in the designated range of tyre sizes. This may be by means of descriptions supplemented by technical data, drawings, photographs and Computer Tomography (CT), and must be sufficient to allow the Type Approval Authority or Technical Service to determine whether any subsequent changes to the major features will adversely affect the tyre performance. The effects of changes to minor details of tyre construction on tyre performances will be evident and determined during checks on conformity of production; a0c0
3.2.2. Drawings or photographs of the tyre sidewall, showing the information given in paragraph 3.1.8. above and the approval marking referred to in paragraph 4., shall be submitted once the production has been established, but no later than one year after the date of granting of type approval. a0c0
3.2.3. In the case of applications relating to special use tyres, a copy of the mould drawing of the tread pattern shall be supplied in order to allow verification of the void-to-fill ratio. a0c0
3.3. At the request of the Type Approval Authority, the applicant shall submit samples of tyres for test or copies of test reports from the Technical Services, communicated as given in paragraph 11. of this Regulation. a0c0
3.4. With regard to the application, testing may be confined to a worst case selection, at the discretion of the Type Approval Authority or designated Technical Service. a0c0
DEL DEL a1c0
4. Markings a0c0
4.1. All tyres constituting the type of tyre shall be marked as prescribed by either Regulation No. 30 or 54, as applicable. a0c0
4.2. In particular tyres shall bear:[10] a0c0
4.2.1. The manufacturer's name or the Brand name/trademark; a1c0
[10] Some of these requirements may be specified separately in Regulation No. 30 or 54. a0c0
4.2.2. The trade description/commercial name (see paragraph 2.4. of this Regulation). However, the trade description is not required when it coincides with the Brand name/trademark; a1c0
4.2.3. The tyre size designation; a0c0
4.2.4. The inscription "REINFORCED" (or alternatively "EXTRA LOAD") if the tyre is classified as reinforced; a0c0
4.2.5. The inscription "TRACTION"[11] if the tyre is classified as "traction tyre"; a0c0
[11] Minimum height of marking: refer to dimension C in Annex 3 of Regulation No. 54. a0c0
4.2.6. The "Alpine" symbol ("3-peak-mountain with snowflake" conforming to the symbol described in Annex 7, Appendix 1) shall be added if the snow tyre is classified as "snow tyre for use in severe snow conditions". a0c0
4.2.7. The inscription "MPT" (or alternatively "ML" or "ET") and /or "POR" if the tyre is classified in the category of use "special". a0c0
... ET means Extra Tread, ML stands for Mining and Logging, MPT means Multi-Purpose Truck and POR means Professional Off-Road. a0c0
4.3. Tyres shall provide adequate space for the approval mark as shown in Annex 2 to this Regulation. a0c0
4.4. The approval mark shall be moulded into or onto the sidewall of the tyre, shall be clearly legible and shall be located in the lower area of the tyre on at least one of the sidewalls. a0c0
4.4.1. However, in the case of tyres identified by the tyre to rim fitment configuration symbol "A", the marking may be located anywhere on the outside sidewall of the tyre. a0c0
5. Approval a0c0
5.1. If the representative tyre size of the type of tyre submitted for approval pursuant to this Regulation meets the requirements of paragraphs 6. and 7. below, approval of that type of tyre shall be granted. a0c0
5.2. An approval number according to Schedule 4 to the Revision 3 of the 1958 Agreement shall be assigned to the type of tyre approved. The same Contracting Party may not assign the same number to another type of tyre. a2c0
5.2.1 Instead of granting the original type approval number pursuant to UN Regulation No. 117, upon the request of the manufacturer, the Type Approval Authority may grant the type approval number, which had been granted before to that type of tyre pursuant to UN Regulations Nos. 30 or 54 with the subsequent extension number. a2c0
5.2.2 The communication form mentioned in paragraph 5.3. below shall identify specific performance parameters of UN Regulation No. 117 by the following suffixes: S To identify additional conformity to the requirements on tyre rolling sound emissions; W To identify additional conformity to the requirements on tyre adhesion on wet surfaces; R To identify additional conformity to the requirements on tyre rolling resistance. a2c0
... Taking into account that two stages are defined for rolling sound and rolling resistance specifications in paragraphs 6.1. and 6.3. below, S and R will be followed either by the suffix "1" for compliance to stage 1 or by the suffix "2" for compliance to stage 2. a2c0
5.3. Notice of approval or extension of approval or refusal of approval of a type of tyre pursuant to this Regulation shall be communicated to the Parties to the Agreement, which apply this Regulation by means of a form conforming to the model in Annex 1 to the Regulation. a0c0
5.3.1. With reference to paragraph 5.2.1. above, tyre manufacturers are entitled to submit an application for extension of type approval to the requirements of other Regulations relevant to the tyre type. In that case, a copy of the relevant type approval communication(s), as issued by the relevant Type Approval Authority, shall be attached to the application for extension of approval. All applications for extension of approval(s) shall only be granted by the Type Approval Authority which issued the original approval for the tyre. a2c0
5.3.1.1. When extension of approval is granted to incorporate into the communication form (see Annex 1 to this Regulation) certification(s) of conformity to other Regulations, DEL (all) the specific type approval number(s) and the Regulation itself shall be added to item 9. of Annex 1 "Communication form a2c0
5.3.1.2. The suffix(es) mentioned in paragraph 5.2.2. above shall be preceded by the two digits identifying the series of amendments of the prescription on tyre performances for UN Regulation No. 117, e.g. 02S2 to identify the second series of amendments on tyre road rolling sound emissions at stage 2 or 02S1WR1 to identify the second series of amendments on tyre road rolling sound emissions at stage 1, tyre adhesion on wet surfaces and rolling resistance at stage 1 (see paragraph 6.1. below for stage 1 and stage 2 definitions).DEL a2c0
5.3.2. The following suffixes have been already reserved to identify specific Regulations on tyre performance parameters: a0c0
... S To identify additional conformity to the requirements on tyre rolling sound emissions; a0c0
... W To identify additional conformity to the requirements on tyre adhesion on wet surfaces; a0c0
... R To identify additional conformity to the requirements on tyre rolling resistance. a0c0
... Taking into account that two stages are defined for rolling sound and rolling resistance specifications in paragraphs 6.1. and 6.3. below, S and R will be followed either by the suffix "1" for compliance to stage 1 or by the suffix "2" for compliance to stage 2. a0c0
5.4. In the space referred to in paragraph 4.3. and in accordance with the requirements of paragraph 4.4. above there shall be affixed to every tyre size, conforming to the type of tyre approved under this Regulation, an international approval mark consisting of: a0c0
5.4.1. A circle surrounding the letter "E" followed by the distinguishing number of the country which has granted approval;[12] and a0c0
[12] The distinguishing numbers of the Contracting Parties to the 1958 Agreement are reproduced in Annex 3 to the Consolidated Resolution on the Construction of Vehicles (R.E.3), document ECE/TRANS/WP.29/78/Rev. 4, Annex 3 - www.unece.org/trans/main/wp29/wp29wgs/wp29gen/wp29resolutions.html a0c0
5.4.2. The part of the approval number specified in paragraph 3 Section 3 of Schedule 4 to the Revision 3 of the 1958 Agreement, which shall be placed close to the circle prescribed in paragraph 5.4.1. above either above or below the "E" or to the left or right of that letter. a2c0
5.4.3. The suffix(es), and the identification to the relevant series of amendments, if any, as specified in the communication form. a0c0
... One of the suffixes listed below or any combination of them can be used. a0c0
... a0c0
... These suffixes shall be placed to the right or below the approval number, if part of the original approval. a0c0
... If the approval is extended subsequent to Regulation No. 30 or 54 approvals, the addition sign "+" and the series of amendment to Regulation No. 117 shall be placed in front of the suffix or any combination of suffixes to denote an extension to the approval. a0c0
... If the approval is extended subsequent to the original approval under Regulation No. 117, the addition sign "+" shall be placed between the suffix or any combination of suffixes of the original approval and the suffix or any combination of suffixes added to denote an extension to the approval. a0c0
5.4.4. The marking on the tyre sidewalls of suffix(es) to the approval number removes the requirement for any additional marking on the tyre of the specific type approval number for conformity to the Regulation(s) to which the suffix refers as per paragraph 5.3.2. above. a0c0
5.5. If the tyre conforms to type approvals under one or more other Regulations annexed to the Agreement in the country which has granted approval under this Regulation, the symbol prescribed in paragraph 5.4.1. above need not be repeated. In such a case the additional numbers and symbols of all the Regulations under which approval has been granted in the country which has granted approval under this Regulation shall be placed adjacent to the symbol prescribed in paragraph 5.4.1. above. a0c0
5.6. Annex 2 to this Regulation gives examples of arrangements of approval marks. a0c0
6. Specifications a0c0
6.1. Rolling sound emission limits, as measured by the method described in Annex 3 to this Regulation. a0c0
6.1.1. For Class C1 tyres, the rolling sound emission value shall not exceed the values pertinent to the applicable stage given below. These values refer to the nominal section width as given in paragraph 2.17.1.1. of Regulation No. 30: a0c0
... a0c0
6.1.2. For Class C2 tyres, the rolling sound emission value with reference to its category of use (see paragraph 2.1., subparagraph (d) above) shall not exceed the values pertinent to the applicable stage given below: a0c0
... a0c0
6.1.3. For Class C3 tyres, the rolling sound emission value with reference to its category of use (see paragraph 2.1., subparagraph (d) above) shall not exceed the values pertinent to the applicable stage given below: a0c0
... a0c0
6.2. The wet grip performance will be based on a procedure that compares either peak brake force coefficient ("pbfc") or mean fully developed deceleration ("mfdd") against values achieved by a standard reference test tyre (SRTT). The relative performance shall be indicated by a wet grip index (G). a0c0
6.2.1. For Class C1 tyres, tested in accordance with either procedure given in Annex 5, Part (A), to this Regulation, the tyre shall meet the following requirements: a0c0
... a0c0
6.2.2. For Class C2 tyres, tested in accordance with either procedure given in Annex 5, Part (B), to this Regulation, the tyre shall meet the following requirements: a0c0
... a0c0
6.2.3. For Class C3 tyres, tested in accordance with either procedure given in Annex 5, Part (B), to this Regulation, the tyre shall meet the following requirements: a0c0
... a0c0
6.3. Rolling resistance coefficient limits, as measured by the method described in Annex 6 to this Regulation. a0c0
6.3.1. The maximum values for stage 1 for the rolling resistance coefficient shall not exceed the following (value in N/kN is equivalent to value in kg/tonne): a0c0
... a0c0
... For "snow tyre for use in severe snow conditions", the limits shall be increased by 1 N/kN. a0c0
6.3.2. The maximum values for stage 2 for the rolling resistance coefficient shall not exceed the following (value in N/kN is equivalent to value in kg/tonne): a0c0
... a0c0
... For "snow tyre for use in severe snow conditions , the limits shall be increased by 1 N/kN. a0c0
6.4. In order to be classified as a "snow tyre for use in severe snow conditions" the tyre shall meet the performance requirements of paragraph 6.4.1. below. The tyre shall meet these requirements based on a test method of Annex 7 by which: a0c0
... (a) The mean fully developed deceleration ("mfdd") in a braking test, a0c0
... (b) Or alternatively an average traction force in a traction test, a0c0
... (c) Or alternatively the average acceleration in an acceleration test a0c0
... of the candidate tyre is compared to that of a standard reference tyre. a0c0
... The relative performance shall be indicated by a snow index. a0c0
6.4.1. Tyre snow performance requirements a0c0
6.4.1.1. Class C1, C2 and C3 tyres a0c0
... The minimum snow index value, as calculated in the procedure described in Annex 7 and compared with the SRTT shall be as follows: a0c0
... a0c0
6.5. In order to be classified as a "traction tyre", a tyre is required to meet at least one of the conditions of paragraph 6.5.1. below. a0c0
6.5.1. The tyre shall have a tread pattern with minimum two circumferential ribs, each containing a minimum of 30 block-like elements, separated by grooves and/or sipe elements the depth of which has to be minimum of one half of the tread depth. The use of an alternative option of a physical test will only apply at a later stage following a further amendment to the Regulation including a reference to an appropriate test methods and limit values. a0c0
6.6. In order to be classified as a "special use tyre" a tyre shall have a block tread pattern in which the blocks are larger and more widely spaced than for normal tyres and have the following characteristics: a0c0
... For C1 tyres: a tread depth ≥ 11 mm and void to fill ratio ≥ 35 per cent a0c0
... For C2 tyres: a tread depth ≥ 11 mm and void to fill ratio ≥ 35 per cent a0c0
... For C3 tyres: a tread depth ≥ 16 mm and void to fill ratio ≥ 35 per cent a0c0
6.7. In order to be classified as a "professional off-road tyre", a tyre shall have all of the following characteristics: a0c0
... (a) For C1 and C2 tyres: a0c0
... (i) A tread depth ≥ 11 mm; a0c0
... (ii) A void-to-fill ratio ≥ 35 per cent; a0c0
... (iii) A maximum speed rating of ≤ Q. a0c0
... (b) For C3 tyres: a0c0
... (i) A tread depth ≥ 16 mm; a0c0
... (ii) A void-to-fill ratio ≥ 35 per cent; a0c0
... (iii) A maximum speed rating of Ͱa K. a0c0
7. Modifications of the type of DEL tyre and extension of approval a1c0
7.1. Every modification of the type of tyre, which may influence the performance characteristics approved in accordance with this Regulation, shall be notified to the Type Approval Authority which approved the type of tyre. That Authority may either: a0c0
7.1.1. Consider that the modifications are unlikely to have any appreciable adverse effect on the performance characteristics approved and that the tyre will comply with the requirements of this Regulation; or a0c0
7.1.2. Require further samples to be submitted for test or further test reports from the designated Technical Service. a0c0
7.1.3. Confirmation or refusal of approval, specifying the modifications, shall be communicated by the procedure given in paragraph 5.3. of this Regulation to the Parties to the Agreement which apply this Regulation. a0c0
7.1.4. The Type Approval Authority granting the extension of approval shall assign a series number for such an extension which shall be shown on the communication form. a0c0
8. Conformity of production a0c0
... The conformity of production procedures shall comply with those set out in the Agreement, Appendix 2 (E/ECE/324-E/ECE/TRANS/505/Rev.2) with the following requirements: a0c0
8.1. Any tyre approved under this Regulation shall be so manufactured as to conform to the performance characteristics of the type of tyre approved and satisfy the requirements of paragraph 6. above; a0c0
8.2. In order to verify conformity as prescribed in paragraph 8.1. above, a random sample of tyres bearing the approval mark required by this Regulation shall be taken from the series production. The normal frequency of verification of conformity of production shall be at least once every two years; a0c0
8.2.1. In the case of verifications with regard to approvals in accordance with paragraph 6.2. of this Regulation, these shall be carried out using the same procedure (see Annex 5 to this Regulation) as that adopted for original approval, and the Type Approval Authority shall satisfy itself that all tyres falling within an approved type comply with the approval requirement. The assessment shall be based upon the production volume of the tyre type at each manufacturing facility, taking into account the quality management system(s) operated by the manufacturer. Where the test procedure involves testing a number of tyres at the same time, for example a set of four tyres for the purpose of testing wet grip performance in accordance with the standard vehicle procedure given in Annex 5 to this Regulation, then the set shall be considered as being one unit for the purposes of calculating the number of tyres to be tested. a0c0
8.3. Production shall be deemed to conform to the requirements of this Regulation if the levels measured comply with the limits prescribed in paragraph 6.1. of this Regulation, with an additional allowance of +1 dB(A) for possible mass production variations. a0c0
8.4. Production shall be deemed to conform to the requirements of this Regulation if the levels measured comply with the limits prescribed in paragraph 6.3. of this Regulation, with an additional allowance of +0.3 N/kN for possible mass production variations. a0c0
9. Penalties for non-conformity of production a0c0
9.1. The approval granted in respect of a type of tyre pursuant to this Regulation may be withdrawn if the requirements laid down in paragraph 8. above are not complied with, or if any tyre of the type of tyre exceeds the limits given in paragraph 8.3. or 8.4. above. a0c0
9.2. If a Party to the Agreement, which applies this Regulation, withdraws an approval, it has previously granted, it shall forthwith notify the other Contracting Parties applying this Regulation by means of a copy of the approval form conforming to the model in Annex 1 to this Regulation. a0c0
10. Production definitively discontinued a0c0
... If the holder of an approval completely ceases to manufacture a type of DELtyre approved in accordance with this Regulation, he shall so inform the Type Approval Authority, which granted the approval. Upon receiving the relevant communication that Authority shall inform thereof the other Parties to the 1958 Agreement applying this Regulation by means of a communication form conforming to the model in Annex 1 to this Regulation. a1c0
11. Names and addresses of Technical Services responsible for conducting approval tests of Type Approval Authorities a0c0
11.1. The Contracting Parties to the 1958 Agreement which apply this Regulation shall communicate to the United Nations Secretariat, the names and addresses of the Technical Services responsible for conducting approval tests and, where applicable, of the approved test laboratories and of the Type Approval Authorities which grant approval and to which forms certifying approval or extension of approval or refusal of approval or withdrawal of approval, or production definitively discontinued, issued in other countries, are to be sent. a1c0
11.2. The Contracting Parties to the 1958 Agreement which apply this Regulation may designate laboratories of tyre manufacturers as approved test laboratories. a1c0
11.3. Where a Contracting Party to the 1958 Agreement applies paragraph 11.2. Above, it may, if it so desires, be represented at the tests by one or more persons of its choice. a1c0
12. Transitional provisions a0c0
12.1. As from the date of entry into force of the 02 series of amendments to this Regulation, Contracting Parties applying this Regulation shall not refuse to grant approval under this Regulation for a type of tyre if the tyre complies with the requirements of the 02 series of amendments, including the stage 1 or stage 2 rolling sound requirements set out in paragraphs 6.1.1. to 6.1.3. of this Regulation, the requirements for wet grip performance set out in paragraph 6.2.1. of this Regulation, and the stage 1 or stage 2 rolling resistance requirements set out in paragraph 6.3.1. or 6.3.2. of this Regulation. a0c0
12.2. As from 1 November 2012, Contracting Parties applying this Regulation shall refuse to grant approval if the tyre type to be approved does not meet the requirements of this Regulation as amended by the 02 series of amendments, and shall, in addition, refuse to grant approval if the stage 2 rolling sound requirements set out in paragraphs 6.1.1. to 6.1.3. of this Regulation, the requirements for wet grip performance set out in paragraph 6.2.1. of this Regulation, and the stage 1 rolling resistance requirements set out in paragraph 6.3.1. of this Regulation are not complied with. a0c0
12.3. As from 1 November 2014, Contracting Parties applying this Regulation may refuse to allow the sale or entry into service of a tyre which does not meet the requirements of this Regulation as amended by the 02 series, and which does not meet the requirements of this Regulation as amended by the 02 series of amendments including the wet grip performance requirements set out in paragraph 6.2.1. of this Regulation. a0c0
12.4. As from 1 November 2016, Contracting Parties applying this Regulation shall refuse to grant approvals if the tyre type to be approved does not meet the requirements of this Regulation as amended by the 02 series of amendments including the stage 2 rolling resistance requirements set out in paragraph 6.3.2. of this Regulation and the wet grip requirements set out in paragraphs 6.2.2. and 6.2.3. of this Regulation. a0c0
12.5. As from 1 November 2016, any Contracting Party applying this Regulation may refuse to allow the sale or entry into service of a tyre which does not meet the requirements of this Regulation as amended by the 02 series, and which does not meet the stage 2 rolling sound requirements set out in paragraphs 6.1.1. to 6.1.3. of this Regulation. a0c0
12.6. As from the dates given below, any Contracting Party applying this Regulation may refuse to allow the sale or entry into service of a tyre which does not meet the requirements of this Regulation as amended by the 02 series, and which does not meet the stage 1 rolling resistance requirements set out in paragraph 6.3.1. of this Regulation: a0c0
... a0c0
12.7. As from the dates given below, any Contracting Party applying this Regulation may refuse to allow the sale or entry into service of a tyre which does not meet the requirements of this Regulation as amended by the 02 series, and which does not meet the stage 2 rolling resistance requirements set out in paragraph 6.3.2. of this Regulation and the wet grip requirements set out in paragraphs 6.2.2. and 6.2.3. of this Regulation: a0c0
... a0c0
12.8. Until 13 February 2019 (60 months after the entry into force of Supplement 4 to the 02 series of amendments to this Regulation) Contracting Parties applying this Regulation may continue to grant type approvals according to the 02 series of amendments to this Regulation, based on the provisions of Annex 4 to this Regulation. a0c0
A1  Annex 1 a0c0
A1  COMMUNICATION a0c0
A1  (maximum format: A4 (210 x 297 mm)) a0c0
A1  a0c0
A1  of a type of tyre with regard to "rolling sound emission level" and/or "adhesion performance on wet surfaces" and/or "rolling resistance" pursuant to Regulation No. 117 a0c0
A1 [1] Distinguishing number of the country which has granted/extended/refused/withdrawn approval (see approval provisions in the Regulation). a0c0
A1 [2] Strike out what does not apply. a0c0
A1  a0c0
A1  Approval No. [3] ................................................................ Suffix(es). [4]........................................................... a2c0
A1 1.

Manufacturer's name and address [DEL]:

a1c0
A1 2. If applicable, name and address of manufacturer's representative: a0c0
A1 3.

"Tyre class" [DEL] of the type of tyre:

a0c0
A1 3.1. Snow tyre for use in severe snow conditions (Yes/No)[2] a0c0
A1 3.2. Traction tyre (Yes/No)[2] a0c0
A1 [3] According to Schedule 4 to Revision 3 of the 1958 Agreement. a2c0
A1 [4] According to paragraphs 5.2.2. and 5.3.1.2. of this Regulation. a2c0
A1 4. Tyre type designation: a1c0
A1 4.1. Brand name(s)/trademark(s) of the type of tyre: a1c0
A1 4.2. Trade description(s)/ Commercial name(s) of the type of tyre: a1c0
A1 5. Technical service and, where applicable, test laboratory approved for purposes of approval or of verification of conformity tests: a1c0
A1 6. Performance(s) approved: sound level at (stage 1/stage 2),[2] wet adhesion level, rolling resistance level (stage 1/stage 2)[2] a0c0
A1 6.1. Sound level of the representative tyre size, see paragraph 2.5. of this Regulation, as per item 7. of the test report in Appendix 1 to Annex 3: ................ dB(A) at reference speed of 70/80 km/h[2] a0c0
A1 6.2. Wet adhesion level of the representative tyre size, see paragraph 2.5. of this Regulation, as per item 7. of the test report in the appendix to Annex 5: ................ (G) using the vehicle or trailer method[2] a0c0
A1 6.3. Rolling resistance level of the representative tyre size, see paragraph 2.5. of this Regulation, as per item 7. of the test report in Appendix 1 to Annex 6 a0c0
A1 6.4. Snow grip level of the representative tyre size, see paragraph 2.5. of Regulation No. 117, as per item 7. of the test report in the appendix 1 to Annex 7: ................ (Snow grip index) using the brake on snow method[2], spin traction method[2] or acceleration method.[2] a0c0
A1 7. Number of report issued by the Technical Service: a0c0
A1 8. Date of report issued by that Service: a0c0
A1 9. Reason(s) of extension (if applicable): a0c0
A1 10. Any remarks: a0c0
A1 11. Place: a0c0
A1 12. Date: a0c0
A1 13. Signature: a0c0
A1 14. Annexed to this communication are: a0c0
A1 14.1. A list of documents in the approval file deposited at the Type Approval Authorities having delivered the approval and which can be obtained upon request. [2] a0c0
A1 14.2. A list of tyre size designations: Specify for each brand name/trademark and/or each trade description/ Commercial name the list of tyre size designations, adding in case of Class C1 tyres the mark "reinforced" (or "extra load") or the speed symbol of snow tyres or in the case of tyres of Classes C2 and C3, the mark "traction", if so required by paragraph 3.1. of this Regulation. a1c0
A1 [3] Appendix 2 for C1 and C2 tyres. a0c0
A1  Appendix 3 for C3 tyres. a0c0
A1 [4] In the case of "snow tyre for use in severe snow conditions" a test report according to Appendix 2 to Annex 7 shall be submitted. a0c0
A2  Annex 2 – Appendix 1 a0c0
A2  Example of approval marks a0c0
A2  Arrangements of approval marks a0c0
A2  (See paragraph 5.4. of this Regulation) a0c0
A2  Approval according to Regulation No. 117 a0c0
A2  a0c0
A2  The above approval mark, affixed to a DELtyre shows that a tyre concerned has been approved in the Netherlands (E 4) pursuant to Regulation No. 117 (marked by S2 (rolling sound at stage 2) only), under approval number 0212345. The first two digits of the approval number (02) indicate that the approval was granted according to the requirements 02 series of amendments to this Regulation. a1c0
A2  a0c0
A2  The above approval mark shows that the tyre concerned has been approved in the Netherlands (E 4) pursuant to Regulation No. 117 (marked by S1 (rolling sound at stage 1) W (wet adhesion), and R1 ( Rolling resistance at stage 1 ) under approval number 0212345. This indicates that the approval is for S1WR1. The first two digits of the approval number (02) indicate that the approval was granted according to the requirements of the 02 series of amendments to this Regulation. a0c0
A2  Annex 2 – Appendix 2 a0c0
A2  Approval according to Regulation No. 117 coincident with approval of Regulation No. 30 or 54 [1] a0c0
A2 [1] Approvals in accordance with Regulation No. 117 for tyres within the scope of Regulation No. 54 currently do not include wet adhesion requirements. a0c0
A2  a0c0
A2  The above approval mark shows that the tyre concerned has been approved in the Netherlands (E 4) pursuant to Regulation No. 117 (marked by S2 (rolling sound at stage 2)), under approval number 0212345 and Regulation No. 30, under approval number 0236378. The first two digits of the approval number (02) indicate that the approval was granted according to the 02 series of amendments and Regulation No. 30 included the 02 series of amendments. a0c0
A2  a0c0
A2  The above approval mark shows that the tyre concerned has been approved in the Netherlands (E 4) pursuant to Regulation No. 117 (marked by S2WR2 (rolling sound at stage 2 wet adhesion and rolling resistance at stage 2)), under approval number 0212345 and Regulation No. 30 under approval number 0236378. The first two digits of the approval number (02) indicate that the approval was granted according to the 02 series of amendments and Regulation No. 30 included the 02 series of amendments. a0c0
A2  a0c0
A2  The above approval mark shows that the tyre concerned has been approved in the Netherlands (E 4) pursuant to Regulation No. 117 and the 02 series of amendments under approval number 0212345 (marked by S2), and Regulation No. 54. This indicates that the approval is for rolling sound stage 2 (S2). The first two digits of the Regulation No. 117 approval number (02) in conjunction with "S2" indicate that the first approval was granted in accordance with Regulation No. 117 which included the 02 series of amendments. The first two digits of Regulation No. 54 (00) indicate that this Regulation was in its original form. a0c0
A2  a0c0
A2  The above approval mark shows that the tyre concerned has been approved in the Netherlands (E 4) pursuant to Regulation No. 117 and the 02 series of amendments under approval number 0212345 (marked by S2 R2), and Regulation No. 54. This indicates that the approval is for rolling sound stage 2 (S2) and rolling resistance stage 2. The first two digits of the Regulation No. 117 approval number (02) in conjunction with "S2R2" indicate that the first approval was granted in accordance with Regulation No. 117 which included the 02 series of amendments. The first two digits of Regulation No. 54 (00) indicate that this Regulation was in its original form. a0c0
A2  Annex 2 – Appendix 3 a0c0
A2  Extensions to combine approvals issued in accordance with Regulations Nos. 117, 30 or 54 [1] a0c0
A2 [1] Approvals in accordance with Regulation No. 117 for tyres within the scope of Regulation No. 54 currently do not include wet adhesion requirements. a0c0
A2  a0c0
A2  The above approval mark shows that the tyre concerned has been initially approved in the Netherlands (E 4) pursuant to Regulation No. 30 and the 02 series of amendments under approval number 0236378. It is also marked by + 02S1 (rolling sound at stage 1) which indicates that its approval is extended under Regulation No. 117 (02 series of amendments). The first two digits of the approval number (02) indicate that the approval was granted according to Regulation No. 30 (02 series of amendments). The addition (+) sign indicates that the first approval was granted in accordance with Regulation No. 30 and has been extended to include the approval(s) granted according to Regulation No. 117 (02 series of amendments) for rolling sound at stage 1. a0c0
A2  a0c0
A2  The above approval mark shows that the tyre concerned has been initially approved in the Netherlands (E 4) pursuant to Regulation No. 30 and the 02 series of amendments under approval number 0236378. This indicates that the approval is for S1 (rolling sound at stage 1) W (wet adhesion) and R2 (rolling resistance at stage 2). The S1WR2 preceded by (02) indicates that it has had its approval extended under Regulation No. 117 which included the 02 series of amendments. The first two digits of the approval number (02) indicate that the approval was granted according to Regulation No. 30 (02 series of amendments). The addition (+) sign indicates that the first approval was granted in accordance with Regulation No. 30 and has been extended to include Regulation No. 117 approval(s) (02 series of amendments). a0c0
A2  Annex 2 – Appendix 4 a0c0
A2  Extensions to combine approvals issued in accordance with Regulation No. 117 [1] a0c0
A2 [1] Approvals in accordance with Regulation No. 117 for tyres within the scope of Regulation No. 54 currently do not include wet adhesion requirements. a0c0
A2  a0c0
A2  The above approval mark shows that the tyre concerned has been initially approved in the Netherlands (E 4) pursuant to Regulation No. 117 and the 02 series of amendments under approval number 0212345. This indicates that the approval is for W (wet grip). The S2R2 preceded by + indicates that it has had its approval extended under Regulation No. 117 to rolling sound at stage 2 and rolling resistance at stage 2 based on separate certificate(s). a0c0
A2  a0c0
A2  The above approval mark shows that the tyre concerned has been initially approved in the Netherlands (E 4) pursuant to Regulation No. 117 and the 02 series of amendments under approval number 0212345. This indicates that the approval is for S1 (rolling sound at stage 1) and W (wet grip). The R1 preceded by + indicates that it has had its approval extended under Regulation No. 117 to rolling resistance at stage 1 based on separate certificate(s). a0c0
A2  a0c0
A2  The above approval mark shows that the tyre concerned has been initially approved in the Netherlands (E 4) pursuant to Regulation No. 117 and the 01 series of amendments under approval number 0167890. This indicates that the approval is for S (rolling sound at stage 1) and W (wet grip). The 02R1 preceded by + indicates that it has had its approval extended under Regulation No. 117 and the 02 series of amendments to rolling resistance at stage 1 based on separate certificate(s). a0c0
A3  Annex 3 a0c0
A3  Coast-by test method for measuring tyre-rolling sound emission a0c0
A3  Introduction a0c0
A3  The presented method contains specifications on measuring instruments, measurement conditions and the measurement method, in order to obtain the sound level of a set of tyres mounted on a test vehicle rolling on a specified road surface. The maximum sound pressure level is to be recorded, when the test vehicle is coasting, by remote-field microphones; the final result for a reference speed is obtained from a linear regression analysis. Such test results cannot be related to tyre rolling sound measured during acceleration under power or deceleration under braking. a0c0
A3 1. Measuring instruments a0c0
A3 1.1. Acoustic measurements a0c0
A3  The sound level meter or the equivalent measuring system, including the windscreen recommended by the manufacturer shall meet or exceed the requirements of Type 1 instruments in accordance with IEC 60651:1979/A1:1993, second edition. a0c0
A3  The measurements shall be made using the frequency weighting A, and the time weighting F. a0c0
A3  When using a system that includes a periodic monitoring of the A-weighted sound level, a reading should be made at a time interval not greater than 30 ms. a0c0
A3 1.1.1. Calibration a0c0
A3  At the beginning and at the end of every measurement session, the entire measurement system shall be checked by means of a sound calibrator that fulfils the requirements for sound calibrators of at least precision Class 1 according to IEC 60942:1988. Without any further adjustment the difference between the readings of two consecutive checks shall be less than or equal to 0.5 dB(A). If this value is exceeded, the results of the measurements obtained after the previous satisfactory check shall be discarded. a0c0
A3 1.1.2. Compliance with requirements a0c0
A3  The compliance of the sound calibration device with the requirements of IEC 60942:1988 shall be verified once a year and the compliance of the instrumentation system with the requirements of IEC 60651:1979/A1:1993, second edition shall be verified at least every two years, by a laboratory which is authorized to perform calibrations traceable to the appropriate standards. a0c0
A3 1.1.3. Positioning of the microphone a0c0
A3  The microphone (or microphones) shall be located at a distance of 7.5 ± 0.05 m from track reference line CC' (Figure 1) and 1.2 ± 0.02 m above the ground. Its axis of maximum sensitivity shall be horizontal and perpendicular to the path of the vehicle (line CC'). a0c0
A3 1.2. Speed measurements a0c0
A3  The vehicle speed shall be measured with instruments with accuracy of ± 1 km/h or better when the front end of the vehicle has reached line PP (Figure 1). a0c0
A3 1.3. Temperature measurements a0c0
A3  Measurements of air as well as test surface temperature are mandatory. a0c0
A3  The temperature measuring devices shall be accurate within ± 1 °C. a0c0
A3 1.3.1. Air temperature a0c0
A3  The temperature sensor is to be positioned in an unobstructed location close to the microphone in such a way that it is exposed to the airflow and protected from direct solar radiation. The latter may be achieved by any shading screen or similar device. The sensor should be positioned at a height of 1.2 ± 0.1 m above the test surface level, to minimize the influence of the test surface thermal radiation at low airflows. a0c0
A3 1.3.2. Test surface temperature a0c0
A3  The temperature sensor is to be positioned in a location where the temperature measured is representative of the temperature in the wheel tracks, without interfering with the sound measurement. a0c0
A3  If an instrument with a contact temperature sensor is used, heat-conductive paste shall be applied between the surface and the sensor to ensure adequate thermal contact. a0c0
A3  If a radiation thermometer (pyrometer) is used, the height should be chosen to ensure that a measuring spot with a diameter of ≥ 0.1 m is covered. a0c0
A3 1.4. Wind measurement a0c0
A3  The device shall be capable of measuring the wind speed with a tolerance of ± 1 m/s. The wind shall be measured at microphone height. The wind direction with reference to the driving direction shall be recorded. a0c0
A3 2. Conditions of measurement a0c0
A3 2.1. Test site a0c0
A3  The test site shall consist of a central section surrounded by a substantially flat test area. The measuring section shall be level; the test surface shall be dry and clean for all measurements. The test surface shall not be artificially cooled during or prior the testing. a0c0
A3  The test track shall be such that the conditions of a free sound field between the sound source and the microphone are attained to within 1 dB(A). These conditions shall be deemed to be met if there is no large sound reflecting objects, such as fences, rocks, bridges or building within 50 m of the centre of the measuring section. The surface of the test track and the dimensions of the test site shall be in accordance with ISO 10844:2014. Until the end of the period indicated in paragraph 12.8. of this Regulation the specifications for the test site may be in accordance with Annex 4 to this Regulation. a0c0
A3  A central part of at least 10 m radius shall be free of powdery snow, tall grass, loose soil, cinders or the like. There shall be no obstacle, which could affect the sound field within the vicinity of the microphone and no persons shall stand between the microphone and the sound source. The operator carrying out the measurements and any observers attending the measurements shall position themselves so as not to affect the readings of the measuring instruments. a0c0
A3 2.2. Meteorological conditions a0c0
A3  Measurements shall not be made under poor atmospheric conditions. It shall be ensured that the results are not affected by gusts of wind. Testing shall not be performed if the wind speed at the microphone height exceeds 5 m/s. a0c0
A3  Measurements shall not be made if the air temperature is below 5 °C or above 40 °C or the test surface temperature is below 5 °C or above 50 °C. a0c0
A3 2.3. Ambient noise a0c0
A3 2.3.1. The background sound level (including any wind noise) shall be at least 10 dB(A) less than the measured tyre rolling sound emission. A suitable windscreen may be fitted to the microphone provided that account is taken of its effect on the sensitivity and directional characteristics of the microphone. a0c0
A3 2.3.2. Any measurement affected by a sound peak which appears to be unrelated to the characteristics of the general sound level of tyres, shall be ignored. a0c0
A3 2.4. Test vehicle requirements a0c0
A3 2.4.1. General a0c0
A3  The test vehicle shall be a motor vehicle and be fitted with four single tyres on just two axles. a0c0
A3 2.4.2. Vehicle load a0c0
A3  The vehicle shall be loaded such as to comply with the test tyre loads as specified in paragraph 2.5.2. below. a0c0
A3 2.4.3. Wheelbase a0c0
A3  The wheelbase between the two axles fitted with the test tyres shall for Class C1 be less than 3.50 m and for Class C2 and Class C3 tyres be less than 5 m. a0c0
A3 2.4.4. Measures to minimize vehicle influence on sound level measurements a0c0
A3  To ensure that tyre rolling sound is not significantly affected by the test vehicle design the following requirements and recommendations are given. a0c0
A3 2.4.4.1. Requirements: a0c0
A3  (a) Spray suppression flaps or other extra device to suppress spray shall not be fitted; a0c0
A3  (b) Addition or retention of elements in the immediate vicinity of the rims and tyres, which may screen the emitted sound, is not permitted; a0c0
A3  (c) Wheel alignment (toe in, camber and caster) shall be in full accordance with the vehicle manufacturer's recommendations; a0c0
A3  (d) Additional sound absorbing material may not be mounted in the wheel housings or under the underbody; a0c0
A3  (e) Suspension shall be in such a condition that it does not result in an abnormal reduction in ground clearance when the vehicle is loaded in accordance with the testing requirement. If available, body level Regulation systems shall be adjusted to give a ground clearance during testing which is normal for unladen condition. a0c0
A3 2.4.4.2. Recommendations to avoid parasitic noise: a0c0
A3  (a) Removal or modification on the vehicle that may contribute to the background noise of the vehicle is recommended. Any removals or modifications shall be recorded in the test report; a0c0
A3  (b) During testing it should be ascertained that brakes are not poorly released, causing brake noise; a0c0
A3  (c) It should be ascertained that electric cooling fans are not operating; a0c0
A3  (d) Windows and sliding roof of the vehicle shall be closed during testing. a0c0
A3 2.5. Tyres a0c0
A3 2.5.1. General a0c0
A3  Four identical tyres shall be fitted on the test vehicle. In the case of tyres with a load capacity index in excess of 121 and without any dual fitting indication, two of these tyres of the same type and range shall be fitted to the rear axle of the test vehicle; the front axle shall be fitted with tyres of size suitable for the axle load and planed down to the minimum depth in order to minimize the influence of tyre/road contact noise while maintaining a sufficient level of safety. Winter tyres that in certain Contracting Parties may be equipped with studs intended to enhance friction shall be tested without this equipment. Tyres with special fitting requirements shall be tested in accordance with these requirements (e.g. rotation direction). The tyres shall have full tread depth before being run-in. a0c0
A3  Tyres are to be tested on rims permitted by the tyre manufacturer. a0c0
A3 2.5.2. Tyre loads a0c0
A3  The test load Qt for each tyre on the test vehicle shall be 50 to 90 per cent of the reference load Qr, but the average test load Qt,avr of all tyres shall be 75 ± 5 per cent of the reference load Qr. a0c0
A3  For all tyres the reference load Qr corresponds to the maximum mass associated with the load capacity index of the tyre. In the case where the load capacity index is constituted by two numbers divided by slash (/), reference shall be made to the first number. a0c0
A3 2.5.3. Tyre inflation pressure a0c0
A3  Each tyre fitted on the test vehicle shall have a test pressure Pt not higher than the reference pressure Pr and within the interval: a0c0
A3  a0c0
A3  For Class C2 and Class C3 the reference pressure Pr is the inflation pressure corresponding to the pressure in kPa or to the pressure index marked on the sidewall. a1c0
A3  For Class C1 the reference pressure is Pr = 250 kPa for "standard" tyres and 290 kPa for "reinforced" or "extra load" tyres; the minimum test pressure shall be Pt = 150 kPa. a0c0
A3 2.5.4. Preparations prior to testing a0c0
A3  The tyres shall be "run-in" prior to testing to remove compound nodules or other tyre pattern characteristics resulting from the moulding process. This will normally require the equivalent of about 100 km of normal use on the road. a0c0
A3  The tyres fitted to the test vehicle shall rotate in the same direction as when they were run-in. a0c0
A3  Prior to testing tyres shall be warmed up by running under test conditions. a0c0
A3 3. Method of testing a0c0
A3 3.1. General conditions a0c0
A3  For all measurements the vehicle shall be driven in a straight line over the measuring section (AA' to BB') in such a way that the median longitudinal plane of the vehicle is as close as possible to the line CC'. a0c0
A3  When the front end of the test vehicle has reached the line AA' the vehicle driver shall have put the gear selector on neutral position and switched off the engine. If abnormal noise (e.g. ventilator, self-ignition) is emitted by the test vehicle during the measurement, the test shall be disregarded. a0c0
A3 3.2. Nature and number of measurements a0c0
A3  The maximum sound level expressed in A-weighted decibels (dB(A)) shall be measured to the first decimal place as the vehicle is coasting between lines AA' and BB' (Figure 1 - front end of the vehicle on line AA', rear end of the vehicle on line BB'). This value will constitute the result of the measurement. a0c0
A3  At least four measurements shall be made on each side of the test vehicle at test speeds lower than the reference speed specified in paragraph 4.1. below and at least four measurements at test speeds higher than the reference speed. The speeds shall be approximately equally spaced over the speed range specified in paragraph 3.3. below. a0c0
A3 3.3. Test speed range a0c0
A3  The test vehicle speeds shall be within the range: a0c0
A3  (a) From 70 to 90 km/h for Class C1 and Class C2 tyres; a0c0
A3  (b) From 60 to 80 km/h for Class C3 tyres. a0c0
A3 4. Interpretation of results a0c0
A3  The measurement shall be invalid if an abnormal discrepancy between the values is recorded (see paragraph 2.3.2. of this annex). a0c0
A3 4.1. Determination of test result a0c0
A3  Reference speed Vref used to determine the final result will be: a0c0
A3  (a) 80 km/h for Class C1 and Class C2 tyres; a0c0
A3  (b) 70 km/h for Class C3 tyres. a0c0
A3 4.2. Regression analysis of rolling sound measurements a0c0
A3  The tyre-road rolling sound level LR in dB(A) is determined by a regression analysis according to: a0c0
A3  a0c0
A3 4.3. Temperature correction a0c0
A3  For Class C1 and Class C2 tyres, the final result shall be normalized to a test surface reference temperature Jref by applying a temperature correction, according to the following: a0c0
A3  a0c0
A3  If the measured test surface temperature does not change more than 5 C within all measurements necessary for the determination of the sound level of one set of tyres, the temperature correction may be made only on the final reported tyre rolling sound level as indicated above, utilizing the arithmetic mean value of the measured temperatures. Otherwise each measured sound level Li shall be corrected, utilizing the temperature at the time of the sound recording. a0c0
A3  There will be no temperature correction for Class C3 tyres. a0c0
A3 4.4. In order to take account of any measuring instrument inaccuracies, the results according to paragraph 4.3. above shall be reduced by 1 dB(A). a0c0
A3 4.5. The final result, the temperature corrected tyre rolling sound level LR(±ref) in dB(A), shall be rounded down to the nearest lower whole value. a0c0
A3  a0c0
A3  Annex 3 – Appendix 1 a0c0
A3  Test report a0c0
A3  Part 1 - Report a0c0
A3 1. Type Approval Authority or Technical Service: a0c0
A3 2. Name and address of applicant: a0c0
A3 3. Test report No.: a0c0
A3 4. Manufacturer and Brand Name or Trade description: a0c0
A3 5. Tyre Class (C1, C2 or C3): a0c0
A3 6. Category of use: a0c0
A3 7. Sound level according to paragraphs 4.4. and 4.5. of Annex 3: ...........dB(A) a0c0
A3  at reference speed of 70/80 km/h[1] a0c0
A3 [1] Strike out what does not apply. a0c0
A3 8. Comments (if any): a0c0
A3 9. Date: a0c0
A3 10. Signature: a0c0
A3  Part 2 - Test data a0c0
A3 1. Date of test: a0c0
A3 2. Test vehicle (Make, model, year, modifications, etc.): a0c0
A3 2.1. Test vehicle wheelbase: mm a0c0
A3 3. Location of test track: a0c0
A3 3.1. Date of track certification to ISO 10844:2014: a0c0
A3 3.2. Issued by: a0c0
A3 3.3. Method of certification: a0c0
A3 4. Tyre test details: a0c0
A3 4.1. Tyre size designation: a0c0
A3 4.2. Tyre service description: a0c0
A3 4.3. Reference inflation pressure: kPa a0c0
A3 4.4. Test data: a0c0
A3  a0c0
A3 4.5. Test rim width code: a0c0
A3 4.6. Temperature measurement sensor type: a0c0
A3 5. Valid test results: a0c0
A3  a0c0
A3 5.1. Regression line slope: a0c0
A3 5.2. Sound level after temperature correction according to paragraph 4.3. of Annex 3: dB(A) a0c0
A4  Annex 3 a0c0
A4  Specifications for the test site [1] a0c0
A4 [1] The specifications for the test site reproduced in this annex are valid until the end of the period indicated in paragraph 12.8. of this Regulation. a0c0
A4 1. Introduction a0c0
A4  This annex describes the specifications relating to the physical characteristics and the laying of the test track. These specifications based on a special standard[2] describe the required physical characteristics as well as the test methods for these characteristics. a0c0
A4 [2] ISO 10844:2014. a0c0
A4 2. Required characteristics of the surface a0c0
A4  A surface is considered to conform to this standard provided that the texture and voids content or sound absorption coefficient have been measured and found to fulfil all the requirements of paragraphs 2.1. to 2.4. below and provided that the design requirements (paragraph 3.2. below) have been met. a0c0
A4 2.1. Residual voids content a0c0
A4  The residual Voids Content (VC) of the test track paving mixture shall not exceed 8 per cent. For the measurement procedure, see paragraph 4.1. of this annex. a0c0
A4 2.2. Sound absorption coefficient a0c0
A4  If the surface fails to comply with the residual voids content requirement, the surface is acceptable only if its sound absorption coefficient is α ≤ 0.10. For the measurement procedure, see paragraph 4.2. below. The requirements of this paragraph 2.1. above are met also if only sound absorption has been measured and found to be α ≤ 0.10. a0c0
A4  Note: The most relevant characteristic is the sound absorption, although the residual voids content is more familiar among road constructors. However, sound absorption needs to be measured only if the surface fails to comply with the voids requirement. This is motivated because the latter is connected with relatively large uncertainties in terms of both measurements and relevance and some surfaces therefore erroneously may be rejected when based only on the voids measurement. a0c0
A4 2.3. Texture depth a0c0
A4  The Texture Depth (TD) measured according to the volumetric method (see paragraph 4.3. below) shall be: a0c0
A4  TD ≥ 0.4 mm a0c0
A4 2.4. Homogeneity of the surface a0c0
A4  Every practical effort shall be taken to ensure that the surface is made to be as homogeneous as possible within the test area. This includes the texture and voids content, but it should also be observed that if the rolling process results in more effective rolling at some places than others, the texture may be different and unevenness causing bumps may also occur. a0c0
A4 2.5. Period of testing a0c0
A4  In order to check whether the surface continues to conform to the texture and voids content or sound absorption requirements stipulated in this standard, periodic testing of the surface shall be done at the following intervals: a0c0
A4  (a) For residual VC or sound absorption (α): a0c0
A4  When the surface is new: a0c0
A4  If the surface meets the requirements when new, no further periodical testing is required. If it does not meet the requirement when it is new, it may do so later because surfaces tend to become clogged and compacted with time; a0c0
A4  (b) For TD: a0c0
A4  When the surface is new: a0c0
A4  When the noise testing starts (Note: Not before four weeks after laying); a0c0
A4  Then every twelve months. a0c0
A4 3. Test surface design a0c0
A4 3.1. Area a0c0
A4  When designing the test track layout it is important to ensure that, as a minimum requirement, the area traversed by the vehicles running through the test strip is covered with the specified test material with suitable margins for safe and practical driving. This will require that the width of the track is at least 3 m and the length of the track extends beyond lines AA and BB by at least 10 m at either end. Figure 1 shows a plan of a suitable test site and indicates the minimum area which shall be machine laid and machine compacted with the specified test surface material. According to Annex 3, paragraph 3.2., measurements have to be made on each side of the vehicle. This can be made either by measuring with two microphone locations (one on each side of the track) and driving in one direction, or measuring with a microphone only on one side of the track but driving the vehicle in two directions. If the latter method is used, then there are no surface requirements on that side of the track where there is no microphone. a0c0
A4  a0c0
A4 3.2. Design and preparation of the surface a0c0
A4 3.2.1. Basic design requirements a0c0
A4  The test surface shall meet four design requirements: a0c0
A4 3.2.1.1. It shall be a dense asphaltic concrete. a0c0
A4 3.2.1.2. The maximum chipping size shall be 8 mm (tolerances allow from 6.3 mm to 10 mm). a0c0
A4 3.2.1.3. The thickness of the wearing course shall be ≥ 30 mm. a0c0
A4 3.2.1.4. The binder shall be a straight penetration grade bitumen without modification. a0c0
A4 3.2.2. Design guidelines a0c0
A4  As a guide to the surface constructor, an aggregate grading curve which will give desired characteristics is shown in Figure 2. In addition, Table 1 gives some guidelines in order to obtain the desired texture and durability. The grading curve fits the following formula: a0c0
A4  a0c0
A4  a0c0
A4  In addition to the above, the following recommendations are given: a0c0
A4  (a) The sand fraction (0.063 mm < square mesh sieve size < 2 mm) shall include no more than 55 per cent natural sand and at least 45 per cent crushed sand; a0c0
A4  (b) The base and sub-base shall ensure a good stability and evenness, according to best road construction practice; a0c0
A4  (c) The chippings shall be crushed (100 per cent crushed faces) and of a material with a high resistance to crushing; a0c0
A4  (d) The chippings used in the mix shall be washed; a0c0
A4  (e) No extra chippings shall be added onto the surface; a0c0
A4  (f) The binder hardness expressed as PEN value shall be 40 - 60, 60 - 80 or even 80 - 100 depending on the climatic conditions of the country. The rule is that as hard a binder as possible shall be used, provided this is consistent with common practice; a0c0
A4  (g) The temperature of the mix before rolling shall be chosen so as to achieve by subsequent rolling the required voids content. In order to increase the probability of satisfying the specifications of paragraphs 2.1. to 2.4. above, the compactness shall be studied not only by an appropriate choice of mixing temperature, but also by an appropriate number of passings and by the choice of compacting vehicle. a0c0
A4  a0c0
A4 4. Test method a0c0
A4 4.1. Measurement of the residual voids content a0c0
A4  For the purpose of this measurement, cores have to be taken from the track in at least four different positions, which are equally distributed in the test area between lines AA and BB (see Figure 1). In order to avoid in homogeneity and unevenness in the wheel tracks, cores should not be taken in wheel tracks themselves, but close to them. Two cores (minimum) should be taken close to the wheel tracks and one core (minimum) should be taken approximately midway between the wheel tracks and each microphone location. a0c0
A4  If there is a suspicion that the condition of homogeneity is not met (see paragraph 2.4. above), cores shall be taken from more locations within the test area. a0c0
A4  The residual voids content has to be determined for each core, then the average value from all cores shall be calculated and compared with the requirement of paragraph 2.1. of this annex. In addition, no single core shall have a voids value, which is higher than 10 per cent. a0c0
A4  The test surface constructor is reminded of the problem, which may arise when the test area is heated by pipes or electrical wires and cores shall be taken from this area. Such installations shall be carefully planned with respect to future core drilling locations. It is recommended to leave a few locations of size approximately 200 mm x 300 mm where there are no wires/pipes or where the latter are located deep enough in order not to be damaged by cores taken from the surface layer. a0c0
A4 4.2. Sound absorption coefficient a0c0
A4  The sound absorption coefficient (normal incidence) shall be measured by the impedance tube method using the procedure specified in ISO 10534-1:1996 or ISO 10534-2:1998. a0c0
A4  Regarding test specimens, the same requirements shall be followed as regarding the residual voids content (see paragraph 4.1. above). The sound absorption shall be measured in the range between 400 Hz and 800 Hz and in the range between 800 Hz and 1,600 Hz (at least at the centre frequencies of third octave bands) and the maximum values shall be identified for both of these frequency ranges. Then these values, for all test scores, shall be averaged to constitute the final result. a0c0
A4 4.3. Volumetric macro-texture measurement a0c0
A4  For the purpose of this standard, texture depth measurements shall be made on at least 10 positions evenly spaced along the wheel tracks of the test strip and the average value taken to compare with the specified minimum texture depth. See Standard ISO 10844:2014 for description of the procedure. a0c0
A4 5. Stability in time and maintenance a0c0
A4 5.1. Age influence a0c0
A4  In common with any other surfaces, it is expected that the tyre rolling sound level measured on the test surface may increase slightly during the first a0c0
A4  6-12 months after construction. a0c0
A4  The surface will achieve its required characteristics not earlier than four weeks after construction. The influence of age on the noise from trucks is generally less than that from cars. a0c0
A4  The stability over time is determined mainly by the polishing and compaction by vehicles driving on the surface. It shall be periodically checked as stated in paragraph 2.5. above. a0c0
A4 5.2. Maintenance of the surface a0c0
A4  Loose debris or dust, which could significantly reduce the effective texture depth shall be removed from the surface. In countries with winter climates, salt is sometimes used for de-icing. Salt may alter the surface temporarily or even permanently in such a way as to increase noise and is therefore not recommended. a0c0
A4 5.3. Repaving the test area a0c0
A4  If it is necessary to repave the test track, it is usually unnecessary to repave more than the test strip (of 3 m width in Figure 1) where vehicles are driving, provided the test area outside the strip met the requirement of residual voids content or sound absorption when it was measured. a0c0
A4 6. Documentation of the test surface and of tests performed on it a0c0
A4 6.1. Documentation of the test surface a0c0
A4  The following data shall be given in a document describing the test surface: a0c0
A4 6.1.1. The location of the test track; a0c0
A4 6.1.2. Type of binder, binder hardness, type of aggregate, maximum theoretical density of the concrete (DR), thickness of the wearing course and grading curve determined from cores from the test track; a0c0
A4 6.1.3. Method of compaction (e.g. type of roller, roller mass, number of passes); a0c0
A4 6.1.4. Temperature of the mix, temperature of the ambient air and wind speed during laying of the surface; a0c0
A4 6.1.5. Date when the surface was laid and contractor; a0c0
A4 6.1.6. All or at least the latest test result, including: a0c0
A4 6.1.6.1. The residual voids content of each core; a0c0
A4 6.1.6.2. The locations in the test area from where the cores for voids measurements have been taken; a0c0
A4 6.1.6.3. The sound absorption coefficient of each core (if measured). Specify the results both for each core and each frequency range as well as the overall average; a0c0
A4 6.1.6.4. The locations in the test area from where the cores for absorption measurement have been taken; a0c0
A4 6.1.6.5. Texture depth, including the number of tests and standard deviation; a0c0
A4 6.1.6.6. The institution responsible for tests according to paragraphs 6.1.6.1. and 6.1.6.2. above and the type of equipment used; a0c0
A4 6.1.6.7. Date of the test(s) and date when the cores were taken from the test track. a0c0
A4 6.2. Documentation of vehicle noise tests conducted on the surface a0c0
A4  In the document describing the vehicle noise test(s) it shall be stated whether all the requirements of this standard were fulfilled or not. Reference shall be given to a document according to paragraph 6.1. above describing the results which verify this. a0c0
A5  Annex 5 a0c0
A5  Test procedures for measuring wet grip a0c0
A5  (A) - C1 category tyres a0c0
A5 1. Reference standards a0c0
A5  The following documents listed apply. a0c0
A5 1.1. ASTM E 303-93 (Reapproved 2008), Standard Test Method for Measuring Surface Frictional Properties Using the British Pendulum Tester. a0c0
A5 1.2. ASTM E 501-08, Standard Specification for Standard Rib Tire for Pavement Skid-Resistance Tests. a0c0
A5 1.3. ASTM E 965-96 (Reapproved 2006), Standard Test Method for Measuring Pavement Macrotexture Depth Using a Volumetric Technique. a0c0
A5 1.4. ASTM E 1136-93 (Reapproved 2003), Standard Specification for a Radial Standard Reference Test Tire P195/75R14. a0c0
A5 1.5. ASTM F 2493-08, Standard Specification for a Radial Standard Reference Test Tire P225/60R16. a0c0
A5 2. Definitions a0c0
A5  For the purposes of testing wet grip of C1 tyres: a0c0
A5 2.1. "Test run" means a single pass of a loaded tyre over a given test track surface. a0c0
A5 2.2. "Test tyre(s)" means a candidate tyre, a reference tyre or a control tyre or tyre set that is used in a test run. a0c0
A5 2.3. "Candidate tyre(s) (T)" means a tyre or a tyre set that is tested for the purpose of calculating its wet grip index. a0c0
A5 2.4. "Reference tyre(s) (R)" means a tyre or a tyre set that has the characteristics indicated in the ASTM F 2493-08 and referred to as the Standard Reference Test Tyre. a0c0
A5 2.5. "Control tyre(s) (C)" means an intermediate tyre or a set of intermediate tyres which is used when the candidate tyre and the reference tyre cannot be directly compared on the same vehicle. a0c0
A5 2.6. "Braking force of a tyre" means the longitudinal force, expressed in newton, resulting from braking torque application. a0c0
A5 2.7. "Braking Force Coefficient of a tyre (BFC)" means the ratio of the braking force to the vertical load. a0c0
A5 2.8. "Peak braking force coefficient of a tyre" means the maximum value of a tyre braking force coefficient that occurs prior to wheel lockup as the braking torque is progressively increased. a0c0
A5 2.9. "Lockup of a wheel" means the condition of a wheel in which its rotational velocity about the wheel spin axis is zero and it is prevented from rotating in the presence of applied wheel torque. a0c0
A5 2.10. "Vertical load" means the load in newton imposed on the tyre perpendicular to the road surface. a0c0
A5 2.11. "Tyre test vehicle" means a dedicated special purpose vehicle which has instruments to measure the vertical and the longitudinal forces on one test tyre during braking. a0c0
A5 2.12. "SRTT14" means the ASTM E 1136-93 (Reapproved 2003), Standard Specification for a Radial Standard Reference Test Tire P195/75R14. a0c0
A5 2.13. "SRTT16" means the ASTM F 2493-08, Standard Specification for a Radial Standard Reference Test Tire P225/60R16. a0c0
A5 3. General test conditions a0c0
A5 3.1. Track characteristics a0c0
A5  The test track shall have the following characteristics: a0c0
A5 3.1.1. The surface shall have a dense asphalt surface with a uniform gradient of not more than 2 per cent and shall not deviate more than 6 mm when tested with a 3 m straight edge. a0c0
A5 3.1.2. The surface shall have a pavement of uniform age, composition, and wear. The test surface shall be free of loose material and foreign deposits. a0c0
A5 3.1.3. The maximum chipping size shall be 10 mm (tolerances permitted from 8 mm to 13 mm). a0c0
A5 3.1.4. The texture depth as measured by a sand patch shall be 0.7 ± 0.3 mm. It shall be measured in accordance with ASTM E 965-96 (Reapproved 2006). a0c0
A5 3.1.5. The wetted frictional properties of the surface shall be measured with either method (a) or (b) in paragraph 3.2. a0c0
A5 3.2. Methods to measure the wetted frictional properties of the surface a0c0
A5 3.2.1. British Pendulum Number (BPN) method (a) a0c0
A5  The British Pendulum Number method shall be as defined in ASTM E 303-93 (Reapproved in 2008). a0c0
A5  Pad rubber component formulation and physical properties shall be as specified in ASTM E 501-08. a0c0
A5  The averaged British Pendulum Number (BPN) shall be between 42 and 60 BPN after temperature correction as follows. a0c0
A5  BPN shall be corrected by the wetted road surface temperature. Unless temperature correction recommendations are indicated by the British pendulum manufacturer, the following formula is used: a0c0
A5  BPN = BPN (measured value) + temperature correction a0c0
A5  Temperature correction = -0.0018 t ^2 + 0.34 t - 6.1 a0c0
A5  Where t is the wetted road surface temperature in degrees Celsius. a0c0
A5  Effects of slider pad wear: the pad shall be removed for maximum wear when the wear on the striking edge of the slider reaches 3.2 mm in the plane of the slider or 1.6 mm vertical to it in accordance with paragraph 5.2.2. and Figure 3 of ASTM E 303-93 (Reapproved 2008). a0c0
A5  For the purpose of checking track surface BPN consistency for the measurement of wet grip on an instrumented passenger car: the BPN values of the test track should not vary over the entire stopping distance so as to decrease the dispersion of test results. The wetted frictional properties of the surface shall be measured five times at each point of the BPN measurement every 10 meters and the coefficient of variation of the averaged BPN shall not exceed 10 per cent. a0c0
A5 3.2.2. ASTM E 1136 Standard Reference Test Tyre method (b) a0c0
A5  By derogation with paragraph 2.4. above, this method uses the reference tyre that has the characteristics indicated in the ASTM E 1136-93 (Reapproved 2003) and referred to as SRTT14. a0c0
A5  The average peak braking force coefficient (µpeak,ave) of the SRTT14 shall be 0.7 ± 0.1 at 65 km/h. a0c0
A5  The average peak braking force coefficient (µpeak,ave) of the SRTT14 shall be corrected for the wetted road surface temperature as follows: a0c0
A5  Peak braking force coefficient (µpeak,ave) = peak braking force coefficient (measured) + temperature correction a0c0
A5  Temperature correction = 0.0035 x (t - 20) a0c0
A5  Where t is the wetted road surface temperature in degrees Celsius. a0c0
A5 3.3. Atmospheric conditions a0c0
A5  The wind conditions shall not interfere with wetting of the surface (wind-shields are allowed). a0c0
A5  Both the wetted surface temperature and the ambient temperature shall be between 2 °C and 20 °C for snow tyres and 5 °C and 35 °C for normal tyres. a0c0
A5  The wetted surface temperature shall not vary during the test by more than 10 C. a0c0
A5  The ambient temperature must remain close to the wetted surface temperature; the difference between the ambient and the wetted surface temperatures must be less than 10 °C. a0c0
A5 4. Testing methods for measuring wet grip a0c0
A5  For the calculation of the wet grip index (G) of a candidate tyre, the wet grip braking performance of the candidate tyre is compared to the wet grip braking performance of the reference tyre on a vehicle travelling straight ahead on a wet, paved surface. It is measured with one of the following methods: a0c0
A5  (a) Vehicle method consisting of testing a set of tyres mounted on an instrumented passenger car; a0c0
A5  (b) Testing method using a trailer towed by a vehicle or a tyre test vehicle, equipped with the test tyre(s). a0c0
A5 4.1. Testing method (a) using an instrumented passenger car a0c0
A5 4.1.1. Principle a0c0
A5  The testing method covers a procedure for measuring the deceleration performance of C1 tyres during braking, using an instrumented passenger car equipped with an Antilock Braking System (ABS), where "instrumented passenger car" means a passenger car that is fitted with the measuring equipment listed in paragraph 4.1.2.2. below for the purpose of this testing method. Starting with a defined initial speed, the brakes are applied hard enough on four wheels at the same time to activate the ABS. The average deceleration is calculated between two pre-defined speeds. a0c0
A5 4.1.2. Equipment a0c0
A5 4.1.2.1. Vehicle a0c0
A5  Permitted modifications on the passenger car are as follows: a0c0
A5  (a) Those allowing the number of tyre sizes that can be mounted on the vehicle to be increased; a0c0
A5  (b) Those permitting automatic activation of the braking device to be installed; a0c0
A5  (c) Any other modification of the braking system is prohibited. a0c0
A5 4.1.2.2. Measuring equipment a0c0
A5  The vehicle shall be fitted with a sensor suitable for measuring speed on a wet surface and distance covered between two speeds. a0c0
A5  To measure vehicle speed, a fifth wheel or non-contact speed-measuring system shall be used. a0c0
A5 4.1.3. Conditioning of the test track and wetting condition a0c0
A5  The test track surface shall be watered at least half an hour prior to testing in order to equalize the surface temperature and water temperature. External watering should be supplied continuously throughout testing. For the whole testing area, the water depth shall be 1.0 ± 0.5 mm, measured from the peak of the pavement. a0c0
A5  The test track should then be conditioned by conducting at least ten test runs with tyres not involved in the test programme at 90 km/h. a0c0
A5 4.1.4. Tyres and rims a0c0
A5 4.1.4.1. Tyre preparation and break-in a0c0
A5  The test tyres shall be trimmed to remove all protuberances on the tread surface caused by mould air vents or flashes at mould junctions. a0c0
A5  Fit the test tyres on rims specified by a recognized tyre and rim standards organization as listed in Appendix 4 to Annex 6 to this Regulation. a0c0
A5 4.1.4.2. Tyre load a0c0
A5  The static load on each axle tyre shall lie between 60 per cent and 90 per cent of the tested tyre load capacity. Tyre loads on the same axle should not differ by more than 10 per cent. a0c0
A5 4.1.4.3. Tyre inflation pressure a0c0
A5  On the front and rear axles, the inflation pressures shall be 220 kPa (for standard- and extra-load tyres). The tyre pressure should be checked just prior to testing at ambient temperature and adjusted if required. a0c0
A5 4.1.5. Procedure a0c0
A5 4.1.5.1. Test run a0c0
A5  The following test procedure applies for each test run. a0c0
A5 4.1.5.1.1. The passenger car is driven in a straight line up to 85 ± 2 km/h. a0c0
A5 4.1.5.1.2. Once the passenger car has reached 85 ± 2 km/h, the brakes are always activated at the same place on the test track referred to as "braking starting point", with a longitudinal tolerance of 5 m and a transverse tolerance of 0.5 m. a0c0
A5 4.1.5.1.3. The brakes are activated either automatically or manually. a0c0
A5 4.1.5.1.3.1. The automatic activation of the brakes is performed by means of a detection system made of two parts, one indexed to the test track and one on board the passenger car. a0c0
A5 4.1.5.1.3.2. The manual activation of the brakes depends on the type of transmission as follows. In both cases, a minimum of 600 N pedal efforts is required. a0c0
A5  For manual transmission, the driver should release the clutch and depress the brake pedal sharply, holding it down as long as necessary to perform the measurement. a0c0
A5  For automatic transmission, the driver should select neutral gear and then depress the brake pedal sharply, holding it down as long as necessary to perform the measurement. a0c0
A5 4.1.5.1.4. The average deceleration is calculated between 80 km/h and 20 km/h. a0c0
A5  If any of the specifications listed above (including speed tolerance, longitudinal and transverse tolerance for the braking starting point, and braking time) are not met when a test run is made, the measurement is discarded and a new test run is made. a0c0
A5 4.1.5.2. Test cycle a0c0
A5  A number of test runs are made in order to measure the wet grip index of a set of candidate tyres (T) according to the following procedure, whereby each test run shall be made in the same direction and up to three different sets of candidate tyres may be measured within the same test cycle: a0c0
A5 4.1.5.2.1. First, the set of reference tyres are mounted on the instrumented passenger car. a0c0
A5 4.1.5.2.2. After at least three valid measurements have been made in accordance with paragraph 4.1.5.1. above, the set of reference tyres is replaced by a set of candidate tyres. a0c0
A5 4.1.5.2.3. After six valid measurements of the candidate tyres are performed, two more sets of candidate tyres may be measured. a0c0
A5 4.1.5.2.4. The test cycle is closed by three more valid measurements of the same set of reference tyres as at the beginning of the test cycle. a0c0
A5  Examples: a0c0
A5  (a) The run order for a test cycle of three sets of candidate tyres (T1 to T3) plus a set of reference tyres (R) would be the following: a0c0
A5  (b) The run order for a test cycle of five sets of candidate tyres (T1 to T5) plus a set of reference tyres (R) would be the following: a0c0
A5 4.1.6. Processing of measurement results a0c0
A5 4.1.6.1. Calculation of the Average Deceleration (AD) a0c0
A5  a0c0
A5  Where: a0c0
A5  Sf is the final speed in m/s; Sf = 20 km/h = 5.556 m/s a0c0
A5  Si is the initial speed in m/s; Si = 80 km/h = 22.222 m/s a0c0
A5  d is the distance covered between Si and Sf in meter. a0c0
A5 4.1.6.2. Validation of results a0c0
A5  The AD coefficient of variation is calculated as follows: a0c0
A5  (Standard deviation / Average) x 100. a0c0
A5  For the reference tyres (R): If the AD coefficient of variation of any two consecutive groups of three tests runs of the reference tyre set is higher than 3 per cent, all data should be discarded and the test repeated for all test tyres (the candidate tyres and the reference tyres). a0c0
A5  For the candidate tyres (T): The AD coefficients of variation are calculated for each candidate tyre set. If one coefficient of variation is higher than 3 per cent, the data should be discarded and the test repeated for that candidate tyre set. a0c0
A5 4.1.6.3. Calculation of adjusted average deceleration (Ra) a0c0
A5  The Average Deceleration (AD) of the reference tyre set used for the calculation of its braking force coefficient is adjusted according to the positioning of each candidate tyre set in a given test cycle. a0c0
A5  This adjusted AD of the reference tyre (Ra) is calculated in m/s^2 in accordance with Table 1 where R1 is the average of the AD values in the first test of the reference tyre set (R) and R2 is the average of the AD values in the second test of the same reference tyre set (R). a0c0
A5  a0c0
A5 4.1.6.4. Calculation of the Braking Force Coefficient (BFC) a0c0
A5  The Braking Force Coefficient (BFC) is calculated for a braking on the two axles according to Table 2 where Ta (a = 1, 2 or 3) is the average of the AD values for each candidate tyre (T) set that is part of a test cycle. a0c0
A5  a0c0
A5 4.1.6.5. Calculation of the wet grip index of the candidate tyre a0c0
A5  The wet grip index of the candidate tyre G(T) is calculated as follows: a0c0
A5  a0c0
A5  Where: a0c0
A5  t is the measured wet surface temperature in degree Celsius when the candidate tyre (T) is tested a0c0
A5  t0 is the wet surface reference temperature condition, t0 = 20 °C for normal tyres and t0 = 10 °C for snow tyres a0c0
A5  BFC(R0) is the braking force coefficient for the reference tyre in the reference conditions, BFC(R0) = 0.68 a0c0
A5  a = -0.4232 and b = -8.297 for normal tyres, a = 0.7721 and b = 31.18 for snow tyres [a is expressed as (1/°C)] a0c0
A5 4.1.7. Wet grip performance comparison between a candidate tyre and a reference tyre using a control tyre a0c0
A5 4.1.7.1. General a0c0
A5  Where the candidate tyre size is significantly different from that of the reference tyre, a direct comparison on the same instrumented passenger car may not be possible. This testing method uses an intermediate tyre, hereinafter called the control tyre as defined in paragraph 2.5. above. a0c0
A5 4.1.7.2. Principle of the approach a0c0
A5  The principle is the use of a control tyre set and two different instrumented passenger cars for the test cycle of a candidate tyre set in comparison with a reference tyre set. a0c0
A5  One instrumented passenger car is fitted with the reference tyre set followed by the control tyre set, the other with the control tyre set followed by the candidate tyre set. a0c0
A5  The specifications listed in paragraphs 4.1.2. to 4.1.4. above apply. a0c0
A5  The first test cycle is a comparison between the control tyre set and the reference tyre set. a0c0
A5  The second test cycle is a comparison between the candidate tyre set and the control tyre set. It is done on the same test track and during the same day as the first test cycle. The wetted surface temperature shall be within ۯ °C of the temperature of the first test cycle. The same control tyre set shall be used for the first and the second test cycles. a0c0
A5  The wet grip index of the candidate tyre G(T) is calculated as follows: a0c0
A5  G(T) = G1 x G2 a0c0
A5  Where: a0c0
A5  G1 is the relative wet grip index of the control tyre (C) compared to the reference tyre (R) calculated as follows: a0c0
A5  a0c0
A5  G2 is the relative wet grip index of the candidate tyre (T) compared to the control tyre (C) calculated as follows: a0c0
A5  a0c0
A5 4.1.7.3. Storage and preservation a0c0
A5  It is necessary that all the tyres of a control tyre set have been stored in the same conditions. As soon as the control tyre set has been tested in comparison with the reference tyre, the specific storage conditions defined in ASTM E 1136-93 (Reapproved 2003) shall be applied. a0c0
A5 4.1.7.4. Replacement of reference tyres and control tyres a0c0
A5  When irregular wear or damage results from tests, or when wear influences the test results, the use of the tyre shall be discontinued. a0c0
A5 4.2. Testing method (b) using a trailer towed by a vehicle or a tyre test vehicle a0c0
A5 4.2.1. Principle a0c0
A5  The measurements are conducted on test tyres mounted on a trailer towed by a vehicle (hereafter referred to as tow vehicle) or on a tyre test vehicle. The brake in the test position is applied firmly until sufficient braking torque is generated to produce the maximum braking force that will occur prior to wheel lockup at a test speed of 65 km/h. a0c0
A5 4.2.2. Equipment a0c0
A5 4.2.2.1. Tow vehicle and trailer or tyre test vehicle a0c0
A5  The tow vehicle or the tyre test vehicle shall have the capability of maintaining the specified speed of 65 ± 2 km/h even under the maximum braking forces. a0c0
A5  The trailer or the tyre test vehicle shall be equipped with one place where the tyre can be fitted for measurement purposes hereafter called 'test position' and the following accessories: a0c0
A5  (a) Equipment to activate brakes in the test position; a0c0
A5  (b) A water tank to store sufficient water to supply the road surface wetting system, unless external watering is used; a0c0
A5  (c) Recording equipment to record signals from transducers installed at the test position and to monitor water application rate if the self-watering option is used. a0c0
A5  The maximum variation of toe-settings and camber angle for the test position shall be within ± 0.5° with maximum vertical load. Suspension arms and bushings shall have sufficient rigidity necessary to minimize free play and ensure compliance under application of maximum braking forces. The suspension system shall provide adequate load-carrying capacity and be of such a design as to isolate suspension resonance. a0c0
A5  The test position shall be equipped with a typical or special automotive brake system which can apply sufficient braking torque to produce the maximum value of braking test wheel longitudinal force at the conditions specified. a0c0
A5  The brake application system shall be able to control the time interval between initial brake application and peak longitudinal force as specified in paragraph 4.2.7.1. below. a0c0
A5  The trailer or the tyre test vehicle shall be designed to accommodate the range of candidate tyre sizes to be tested. a0c0
A5  The trailer or the tyre test vehicle shall have provisions for adjustment of vertical load as specified in paragraph 4.2.5.2. below a0c0
A5 4.2.2.2. Measuring equipment a0c0
A5  The test wheel position on the trailer or the tyre test vehicle shall be equipped with a rotational wheel velocity measuring system and with transducers to measure the braking force and vertical load at the test wheel. a0c0
A5  General requirements for measurement system: The instrumentation system shall conform to the following overall requirements at ambient temperatures between 0 °C and 45 °C: a0c0
A5  (a) Overall system accuracy, force: ± 1.5 per cent of the full scale of the vertical load or braking force; a0c0
A5  (b) Overall system accuracy, speed: ± 1.5 per cent of speed or ± 1.0 km/h, whichever is greater. a0c0
A5  Vehicle speed: To measure vehicle speed, a fifth wheel or non-contact precision speed-measuring system should be used. a0c0
A5  Braking forces: The braking force-measuring transducers shall measure longitudinal force generated at the tyre-road interface as a result of brake application within a range from 0 per cent to at least 125 per cent of the applied vertical load. The transducer design and location shall minimize inertial effects and vibration-induced mechanical resonance. a0c0
A5  Vertical load: The vertical load-measuring transducer shall measure the vertical load at the test position during brake application. The transducer shall have the same specifications as described previously. a0c0
A5  Signal conditioning and recording system: All signal conditioning and recording equipment shall provide linear output with necessary gain and data reading resolution to meet the specified previous requirements. In addition, the following requirements apply: a0c0
A5  (a) The minimum frequency response shall be flat from 0 Hz to 50 Hz (100 Hz) within ± 1 per cent full scale; a0c0
A5  (b) The signal-to-noise ratio shall be at least 20/1; a0c0
A5  (c) The gain shall be sufficient to permit full-scale display for full-scale input signal level; a0c0
A5  (d) The input impedance shall be at least ten times larger than the output impedance of the signal source; a0c0
A5  (e) The equipment shall be insensitive to vibrations, acceleration, and changes in ambient temperature. a0c0
A5 4.2.3. Conditioning of the test track a0c0
A5  The test track should be conditioned by conducting at least ten test runs with tyres not involved in the test program at 65 ± 2 km/h. a0c0
A5 4.2.4. Wetting conditions a0c0
A5  The tow vehicle and trailer or the tyre test vehicle may be optionally equipped with a pavement-wetting system, less the storage tank, which, in the case of the trailer, is mounted on the tow vehicle. The water being applied to the pavement ahead of the test tyres shall be supplied by a nozzle suitably designed to ensure that the water layer encountered by the test tyre has a uniform cross section at the test speed with a minimum splash and overspray. a0c0
A5  The nozzle configuration and position shall ensure that the water jets are directed towards the test tyre and pointed towards the pavement at an angle of 20° to 30°. a0c0
A5  The water shall strike the pavement 250 mm to 450 mm ahead of the centre of tyre contact. The nozzle shall be located 25 mm above the pavement or at the minimum height required to clear obstacles which the tester is expected to encounter, but in no case more than 100 mm above the pavement. a0c0
A5  The water layer shall be at least 25 mm wider than the test tyre tread and applied so the tyre is centrally located between the edges. Water delivery rate shall ensure a water depth of 1.0 ± 0.5 mm and shall be consistent throughout the test to within ± 10 per cent. The volume of water per unit of wetted width shall be directly proportional to the test speed. The quantity of water applied at 65 km/h shall be 18 l/s per meter of width of wetted surface in case of a water depth of 1.0 mm. a0c0
A5 4.2.5. Tyres and rims a0c0
A5 4.2.5.1. Tyre preparation and break-in a0c0
A5  The test tyres shall be trimmed to remove all protuberances on the tread surface caused by mould air vents or flashes at mould junctions. a0c0
A5  The test tyre shall be mounted on the test rim declared by the tyre manufacturer. a0c0
A5  A proper bead seat should be achieved by the use of a suitable lubricant. Excessive use of lubricant should be avoided to prevent slipping of the tyre on the wheel rim. a0c0
A5  The test tyres/rim assemblies shall be stored in a location for a minimum of two hours such that they all have the same ambient temperature prior to testing. They should be shielded from the sun to avoid excessive heating by solar radiation. a0c0
A5  For tyre break-in, two braking runs shall be performed under the load, pressure and speed as specified in paragraphs 4.2.5.2, 4.2.5.3 and 4.2.7.1 respectively. a0c0
A5 4.2.5.2. Tyre load a0c0
A5  The test load on the test tyre is 75 ± 5 per cent of the tyre load capacity. a0c0
A5 4.2.5.3. Tyre inflation pressure a0c0
A5  The test tyre cold inflation pressure shall be 180 kPa for standard-load tyres. For extra-load tyres, the cold inflation pressure shall be 220 kPa. a0c0
A5  The tyre pressure should be checked just prior to testing at ambient temperature and adjusted if required. a0c0
A5 4.2.6. Preparation of the tow vehicle and trailer or the tyre test vehicle a0c0
A5 4.2.6.1. Trailer a0c0
A5  For one axle trailers, the hitch height and transverse position shall be adjusted once the test tyre has been loaded to the specified test load in order to avoid any disturbance of the measuring results. The longitudinal distance from the centre line of the articulation point of the coupling to the transverse centre line of the axle of the trailer shall be at least ten times the "hitch height" or the "coupling (hitch) height". a0c0
A5 4.2.6.2. Instrumentation and equipment a0c0
A5  Install the fifth wheel, when used, in accordance with the manufacturer's specifications and locate it as near as possible to the mid-track position of the tow trailer or the tyre test vehicle. a0c0
A5 4.2.7. Procedure a0c0
A5 4.2.7.1. Test run a0c0
A5  The following procedure applies for each test run: a0c0
A5 4.2.7.1.1. The tow vehicle or the tyre test vehicle is driven onto the test track in a straight line at the specified test speed 65 ± 2 km/h. a0c0
A5 4.2.7.1.2. The recording system is launched. a0c0
A5 4.2.7.1.3. Water is delivered to the pavement ahead of the test tyre approximately 0.5 s prior to brake application (for internal watering system). a0c0
A5 4.2.7.1.4. The trailer brakes are activated within 2 meters of a measurement point of the wetted frictional properties of the surface and sand depth in accordance with paragraphs 3.1.4. and 3.1.5. above. The rate of braking application shall be such that the time interval between initial application of force and peak longitudinal force is in the range 0.2 s to 0.5 s. a0c0
A5 4.2.7.1.5. The recording system is stopped. a0c0
A5 4.2.7.2. Test cycle a0c0
A5  A number of test runs are made in order to measure the wet grip index of the candidate tyre (T) according to the following procedure, whereby each test run shall be made from the same spot on the test track and in the same direction. Up to three candidate tyres may be measured within the same test cycle, provided that the tests are completed within one day. a0c0
A5 4.2.7.2.1. First, the reference tyre is tested. a0c0
A5 4.2.7.2.2. After at least six valid measurements are performed in accordance with paragraph 4.2.7.1. above, the reference tyre is replaced by the candidate tyre. a0c0
A5 4.2.7.2.3. After six valid measurements of the candidate tyre are performed, two more candidate tyres may be measured. a0c0
A5 4.2.7.2.4. The test cycle is closed by six more valid measurements of the same reference tyre as at the beginning of the test cycle. a0c0
A5 Examples: a0c0
A5  (a) The run order for a test cycle of three candidate tyres (T1 to T3) plus the reference tyre (R) would be the following: a0c0
A5  R-T1-T2-T3-R a0c0
A5  (b) The run order for a test cycle of five candidate tyres (T1 to T5) plus the reference tyre R would be the following: a0c0
A5  R-T1-T2-T3-R-T4-T5-R a0c0
A5 4.2.8. Processing of measurement results a0c0
A5 4.2.8.1. Calculation of the peak braking force coefficient a0c0
A5  The tyre peak braking force coefficient (µpeak) is the highest value of µ(t) before lockup occurs calculated as follows for each test run. Analogue signals should be filtered to remove noise. Digitally recorded signals must be filtered using a moving average technique. a0c0
A5  a0c0
A5  Where: a0c0
A5  µ(t) is the dynamic tyre braking force coefficient in real time; a0c0
A5  fh(t) is the dynamic braking force in real time, in N; a0c0
A5  fv(t) is the dynamic vertical load in real time, in N. a0c0
A5 4.2.8.2. Validation of results a0c0
A5  The µpeak coefficient of variation is calculated as follows: a0c0
A5  (Standard deviation / Average) x 100 a0c0
A5  For the reference tyre (R): If the coefficient of variation of the peak braking force coefficient (µpeak) of the reference tyre is higher than 5 per cent, all data should be discarded and the test repeated for all test tyres (the candidate tyre(s) and the reference tyre). a0c0
A5  For the candidate tyre(s) (T): The coefficient of variation of the peak braking force coefficient (µpeak) is calculated for each candidate tyre. If one coefficient of variation is higher than 5 per cent, the data should be discarded and the test repeated for this candidate tyre. a0c0
A5 4.2.8.3. Calculation of the adjusted average peak braking force coefficient a0c0
A5  The average peak braking force coefficient of the reference tyre used for the calculation of its braking force coefficient is adjusted according to the positioning of each candidate tyre in a given test cycle. a0c0
A5  This adjusted average peak braking force coefficient of the reference tyre (Ra) is calculated in accordance with Table 3 where R1 is the average peak tyre braking coefficient in the first test of the reference tyre (R) and R2 is the average peak tyre braking coefficient in the second test of the same reference tyre (R). a0c0
A5  a0c0
A5 4.2.8.4 Calculation of the average peak braking coefficient (µpeak,ave) a0c0
A5  The average value of the peak braking coefficients (µpeak,ave) is calculated according to Table 4 whereby Ta (a = 1, 2 or 3) is the average of the peak braking force coefficients measured for one candidate tyre within one test cycle. a0c0
A5  a0c0
A5 4.2.8.5. Calculation of the wet grip index of the candidate tyre a0c0
A5  The wet grip index of the candidate tyre (G(T)) is calculated as follows: a0c0
A5  a0c0
A5  Where: a0c0
A5  t is the measured wet surface temperature in degree Celsius when the candidate tyre (T) is tested a0c0
A5  t0 is the wet surface reference temperature condition a0c0
A5  t0 = 20 °C for normal tyres t0=10 °C for snow tyres a0c0
A5  µpeak,ave(R0) = 0.85 is the peak braking force coefficient for the reference tyre in the reference conditions a0c0
A5  a = -0.4232 and b = -8.297 for normal tyres, a = 0.7721 and b = 31.18 for snow tyres [a is expressed as (1/°C)]. a0c0
A5  (B) - C2 and C3 category tyres a0c0
A5 1. General test conditions a0c0
A5 1.1. Track characteristics a0c0
A5  The surface shall be a dense asphalt surface with a uniform gradient of not more than two per cent and shall not deviate more than 6 mm when tested with a 3 m straight edge. a0c0
A5  The test surface shall have a pavement of uniform age, composition, and wear. The test surface shall be free of loose material or foreign deposits. a0c0
A5  The maximum chipping size shall be from 8 mm to 13 mm. a0c0
A5  The sand depth measured as specified in EN13036-1:2001 and ASTM E 965-96 (reapproved 2006) shall be 0.7 ± 0.3 mm. a0c0
A5  The surface friction value for the wetted track shall be established by one or other of the following methods according to the discretion of the Contracting Party. a0c0
A5 1.1.1. Standard Reference Test Tyre (SRTT) method a0c0
A5  The average peak braking coefficient (µpeak average) of the ASTM E1136 -93 (reapproved 2003) reference tyre (Test method using a trailer or a tyre test vehicle as specified in clause 2.1) shall be 0.7 +/- 0.1 (at 65 km/h and 180 kPa). The measured values shall be corrected for the effects of temperature as follows: a0c0
A5  pbfc = pbfc (measured) + 0.0035 ⋅ (t - 20) a0c0
A5  Where "t" is the wetted track surface temperature in degrees Celsius. a0c0
A5  The test shall be conducted using the lanes and length of the track to be used for the wet grip test. a0c0
A5  For the trailer method, testing is run in such a way that braking occurs within 10 meters distance of where the surface was characterized. a0c0
A5 1.1.2. British Pendulum Number (BPN) method a0c0
A5  The averaged British Pendulum Number (BPN) British Pendulum Tester method as specified in ASTM E 303-93 (reapproved 2008) using the Pad as specified in ASTM E 501-08 shall be (50 ± 10) BPN after temperature correction. a0c0
A5  BPN shall be corrected by the wetted road surface temperature. Unless temperature correction recommendations are indicated by the British pendulum manufacturer the following formula can be used: a0c0
A5  BPN = BPN (measured value) - (0.0018 ⋅ t^2) + 0.34 ⋅ t - 6.1 a0c0
A5  Where: "t" is the wetted road surface temperature in degrees Celsius. a0c0
A5  Effects of slider pad wear: the pad should be removed for maximum wear when the wear on the striking edge of the slider reaches 3.2 mm in the plane of the slider or 1.6 mm vertical to it. a0c0
A5  Check the test track testing surface BPN consistency for the measurement of wet grip on a standard vehicle. a0c0
A5  In the lanes of the track to be used during the wet grip tests, the BPN shall be measured at intervals of 10 m along the length of the lanes. The BPN shall be measured 5 times at each point and the coefficient of variation of the BPN averages shall not exceed 10 per cent. a0c0
A5 1.1.3. The Type Approval Authority shall satisfy itself of the characteristics of the track on the basis of evidence produced in test reports. a0c0
A5 1.2. The surface may be wetted from the track-side or by a wetting system incorporated into the test vehicle or the trailer. a0c0
A5  If a track-side system is used, the test surface shall be wetted for at least half an hour prior to testing in order to equalize the surface temperature and water temperature. It is recommended that track-side wetting be continuously applied throughout testing. a0c0
A5  The water depth shall be between 0.5 and 2.0 mm. a0c0
A5 1.3. The wind conditions shall not interfere with wetting of the surface (wind-shields are permitted). a0c0
A5  The ambient and the wetted surface temperature shall be between 5 °C and 35 °C and shall not vary during the test by more than 10 °C. a0c0
A5 1.4. In order to cover the range of the tyre sizes fitting the commercial vehicles, three Standard Reference Testing Tyre (SRTT) sizes shall be used to measure the relative wet index: a0c0
A5  (a) SRTT 315/70R22.5 LI=154/150, ASTM F2870 a0c0
A5  (b) SRTT 245/70R19.5 LI=136/134, ASTM F2871 a0c0
A5  (c) SRTT 225/75 R 16 C LI=116/114, ASTM F2872 a0c0
A5  The three standard reference testing tyre sizes shall be used to measure the relative wet index as shown in the following table: a0c0
A5  a0c0
A5 2. Test procedure a0c0
A5  The comparative wet grip performance shall be established using either: a0c0
A5  (a) A trailer or special purpose tyre evaluation vehicle; or a0c0
A5  (b) A standard production vehicle (M2, M3, N1, N2 or N3, category) as defined in the Consolidated Resolution on the Construction of Vehicles (R.E.3.) contained in ECE/TRANS/WP.29/78/Rev.4, para. 2. a0c0
A5 2.1. Trailer or special purpose tyre evaluation vehicle procedure a0c0
A5 2.1.1. The measurements are conducted on (a) tyre(s) mounted on a trailer towed by a vehicle or a tyre test vehicle. a0c0
A5  The brake on the test position is applied firmly until sufficient braking torque results to produce maximum braking force that will occur prior to wheel lockup at a test speed of 50 km/h. The trailer, together with the towing vehicle, or the tyre evaluation vehicle shall comply with the following requirements: a0c0
A5 2.1.1.1. Be capable of exceeding the upper limit for the test speed of 50 km/h and of maintaining the test speed requirement of (50 ± 2) km/h even at the maximum level of application of braking forces; a0c0
A5 2.1.1.2. Be equipped with an axle providing one test position having an hydraulic brake and actuation system that can be operated at the test position from the towing vehicle if applicable. The braking system shall be capable of providing sufficient braking torque to achieve the peak brake force coefficient over the range of tyre sizes and tyre loads to be tested; a0c0
A5 2.1.1.3. Be capable of maintaining longitudinal alignment (toe) and camber of the test wheel and tyre assembly throughout the test within ± 0.5° of the static figures achieved at the test tyre loaded condition; a0c0
A5 2.1.1.4. In the case a track wetting system is incorporated: a0c0
A5  The system shall be able to deliver the water such that the tyre and track surface in front of the tyre are wetted before the start of braking and throughout the duration of the test. The apparatus may be optionally equipped with a pavement-wetting system, less the storage tank, which, in the case of the trailer, is mounted on the tow vehicle. The water being applied to the pavement ahead of the test tyres shall be supplied by a nozzle suitably designed to ensure that the water layer encountered by the test tyre has a uniform cross section at the test speed with a minimum splash and overspray. a0c0
A5  The nozzle configuration and position shall ensure that the water jets shall be directed toward the test tyre and pointed toward the pavement at an angle of 15 to 30°. The water shall strike the pavement 0.25 to 0.5 m ahead of the centre of tyre contact. The nozzle shall be located 100 mm above the pavement or the minimum height required to clear obstacles which the tester is expected to encounter, but in no case more than 200 mm above the pavement. The water layer shall be at least 25 mm wider than the test tyre tread and applied so the tyre is centrally located between the edges. The volume of water per unit of wetted width shall be directly proportional to the test speed. The quantity of water applied at 50 km/h shall be 14 l/s per meter of the width of the wetted surface. The nominal values of rate of water application shall be maintained within ± 10 per cent. a0c0
A5 2.1.2. Test procedure a0c0
A5 2.1.2.1. Fit the test tyres on rims specified by a recognized tyre and rim standards organization as listed in Appendix 4 to Annex 6 to this Regulation. Ensure proper bead seating by the use of a suitable lubricant. Excessive use of lubricant should be avoided to prevent slipping of the tyre on the wheel rim. a0c0
A5  Check the test tyres for the specified inflation pressure at ambient temperature (cold), just prior to testing. For the purpose of this standard the testing tyre cold inflation pressure Pt shall be calculated as follows: a0c0
A5  a0c0
A5  Where: a0c0
A5  Pr = Inflation pressure marked on the sidewall. If Pr is not marked on the sidewall refer to the specified pressure in applicable tyre standards manuals corresponding to maximum load capacity for single applications a0c0
A5  Qt = The static test load of the tyre a0c0
A5  Qr = The maximum mass associated with the load capacity index of the tyre a0c0
A5 2.1.2.2. For tyre break-in, two braking runs are performed. The tyre shall be conditioned for a minimum of two hours adjacent to the test track such that it is stabilized at the ambient temperature of the test track area. The tyre(s) shall not be exposed to direct sunshine during conditioning. a0c0
A5 2.1.2.3. The load conditions for testing shall be 75 ± 5 per cent of the value corresponding to the load index. a0c0
A5 2.1.2.4. Shortly before testing, the track shall be conditioned by carrying out at least ten braking test runs at 50 km/h on the part of the track to be used for the performance test programme but using a tyre not involved in that programme; a0c0
A5 2.1.2.5. Immediately prior to testing, the tyre inflation pressure shall be checked and reset, if necessary, to the values given in paragraph 2.1.2.1. a0c0
A5 2.1.2.6. The test speed shall be at 50 ± 2 km/h and shall be maintained between these limits throughout the test run. a0c0
A5 2.1.2.7. The direction of the test shall be the same for each set of tests and shall be the same for the test tyre as that used for the SRTT with which its performance is to be compared. a0c0
A5 2.1.2.8. Deliver water to the pavement ahead of the test tyre approximately 0.5 s prior to brake application (for internal watering system). The brakes of the test wheel assembly shall be applied such that peak braking force is achieved within 0.2 s and 1.0 s of brake application. a0c0
A5 2.1.2.9. For new tyres, the first two braking runs are discarded for tyre break-in. a0c0
A5 2.1.2.10. For the evaluation of the performance of any tyre compared with that of the SRTT, the braking test should be run at the same area on the test pad. a0c0
A5 2.1.2.11. The order of testing shall be: a0c0
A5  R1 - T - R2 a0c0
A5  Where: a0c0
A5  R1 = the initial test of the SRTT, a0c0
A5  R2 = the repeat test of the SRTT and a0c0
A5  T = the test of the candidate tyre to be evaluated. a0c0
A5  A maximum of three candidate tyres may be tested before repeating the SRTT test, for example: a0c0
A5  R1 - T1 - T2 - T3 - R2 a0c0
A5 2.1.2.12. Calculate the peak braking force coefficient, peak, for each test using the following equation: a0c0
A5  a0c0
A5  Where: a0c0
A5  µ(t) = dynamic tyre braking force coefficient in real time, a0c0
A5  fh(t) = dynamic braking force in real time, N, a0c0
A5  fv(t) = dynamic vertical load in real time, N a0c0
A5  Using equation (1) for dynamic tyre braking force coefficient, calculate the peak tyre braking force coefficient, µpeak, by determining the highest value of µ(t) before lockup occurs. Analogic signals should be filtered to remove noise. Digitally recorded signals may be filtered using a moving average technique. a0c0
A5  Calculate the average values of peak-braking coefficient (µpeak, ave) by averaging four or more valid repeated runs for each set of test and reference tyres for each test condition provided that the tests are completed within the same day. a0c0
A5 2.1.2.13. Validation of results a0c0
A5  For the reference tyre: a0c0
A5  If the coefficient of variation of the peak braking coefficient, which is calculated by "standard deviation/average x 100" of the reference tyre is higher than five per cent, discard all data and repeat the test for this reference tyre. a0c0
A5  For the candidate tyres: a0c0
A5  The coefficients of variation (standard deviation/average x 100) are calculated for all the candidate tyres. If one coefficient of variation is greater than five per cent, discard the data for this candidate tyre and repeat the test. a0c0
A5  If R1 is the average of the peak braking coefficient in the first test of the reference tyre, R2 is the average of the peak braking coefficient in the second test of the reference tyre, the following operations are performed, according to the following table: a0c0
A5  a0c0
A5 2.1.2.14. The wet grip index (G) shall be calculated as: a0c0
A5  Wet grip index (G) = µpeak,ave (T)/µpeak, ave (R) a0c0
A5  It represents the relative Wet Grip Index for braking performance of the candidate tyre (T) compared to the reference tyre (R). a0c0
A5 2.2. Standard vehicle procedure a0c0
A5 2.2.1. The vehicle used shall have two axles and be equipped with an anti-lock braking system (e.g. standard production vehicle of M2, M3, N1, N2 or N3 category). The ABS shall continue to fulfil the utilisation of adhesion requirements defined in the Regulations as appropriate, and shall be comparable and constant throughout the tests with the different tyres mounted. a0c0
A5 2.2.1.1. Measuring equipment a0c0
A5  The vehicle shall be fitted with a sensor suitable for measuring speed on a wet surface and distance covered between two speeds. a0c0
A5  To measure vehicle speed, a fifth wheel or non-contact speed-measuring system shall be used. a0c0
A5  The following tolerances shall be respected: a0c0
A5  (a) For the speed measurements: ± 1 per cent or ± 0.5 km/h whichever is greater; a0c0
A5  (b) For the distance measurements: ± 0.1m. a0c0
A5  A display of the measured speed or the difference between the measured speed and the reference speed for the test can be used inside the vehicle so that the driver can adjust the speed of the vehicle. a0c0
A5  A data acquisition system can be also used for storing the measurements. a0c0
A5 2.2.2. Test procedure a0c0
A5  Starting with a defined initial speed, the brakes are applied hard enough on the two axles at the same time to activate the ABS system. a0c0
A5 2.2.2.1. The Average Deceleration (AD) is calculated between two defined speeds, with an initial speed of 60 km/h and a final speed of 20 km/h. a0c0
A5 2.2.2.2. Vehicle equipment a0c0
A5  The rear axle may be indifferently fitted with 2 or 4 tyres. a0c0
A5  For the reference tyre testing, both axles are fitted with reference tyres. (A total of 4 or 6 reference tyres depending on the choice above mentioned). a0c0
A5  For the candidate tyre testing, 3 fitting configurations are possible: a0c0
A5  (a) Configuration "Configuration 1": Candidate tyres on front and rear axles: it is the standard configuration that should be used every time it is possible. a0c0
A5  (b) Configuration "Configuration 2": Candidate tyres on front axle and reference tyre or control tyre on rear axle: allowed in such cases where fitting the candidate tyre on the rear position is not possible. a0c0
A5  (c) Configuration "Configuration 3": Candidate tyres on rear axle and reference tyre or control tyre on front axle: permitted in such cases where fitting the candidate tyre on the front position is not possible. a0c0
A5 2.2.2.3. Tyre inflation pressure a0c0
A5  (a) For a vertical load higher or equal to 75 per cent of the load capacity of the tyre, the test inflation pressure "Pt" shall be calculated as follows: a0c0
A5  a0c0
A5  Pr = Inflation pressure marked on the sidewall. If Pr is not marked on the sidewall refer to the specified pressure in applicable tyre standards manuals corresponding to maximum load capacity for single applications a0c0
A5  Qt = static test load of the tyre a0c0
A5  Qr = maximum mass associated with the load capacity index of the tyre a0c0
A5  (a) For a vertical load lower than 75 per cent of the load capacity of the tire, the test inflation pressure Pt shall be calculated as follows: a0c0
A5  a0c0
A5  Pr = Inflation pressure marked on the sidewall. a0c0
A5  If Pr is not marked on the sidewall refer to the specified pressure in applicable tyre standard manuals corresponding to maximum load capacity for single applications. a0c0
A5  Check the tyre pressure just prior to testing at ambient temperature. a0c0
A5 2.2.2.4. Tyre load a0c0
A5  The static load on each axle shall remain the same throughout the test procedure. The static load on each tyre shall lie between 60 per cent and 100 per cent of the candidate tyre's load capacity. This value shall not exceed 100 per cent of the load capacity of the reference tyre. a0c0
A5  Tyre load on the same axle should not differ by more than 10 per cent. a0c0
A5  The use of fitting as per Configurations 2 and 3 shall fulfil the following additional requirements: a0c0
A5  Configuration 2: Front axle load > Rear axle load a0c0
A5  The rear axle may be indifferently fitted with 2 or 4 tyres a0c0
A5  Configuration 3: Rear axle load > Front axle load x 1.8 a0c0
A5 2.2.2.5. Tyre preparation and break-in a0c0
A5 2.2.2.5.1. The test tyre shall be mounted on the test rim declared by the tyre manufacturer. a0c0
A5  Ensure proper bead seating by the use of a suitable lubricant. Excessive use of lubricant should be avoided to prevent slipping of the tyre on the wheel rim. a0c0
A5 2.2.2.5.2. Place the fitted test tyres in a location for a minimum of two hours such that they all have the same ambient temperature prior to testing, and shield them from the sun to avoid excessive heating by solar radiation. For tyre break-in, perform two braking runs. a0c0
A5 2.2.2.5.3. Condition the pavement by conducting at least ten test runs with tyres not involved in the test programme at an initial speed higher or equal to 65 km/h (which is higher than the initial test speed to guarantee that a sufficient length of track is conditioned). a0c0
A5 2.2.2.6. Procedure a0c0
A5 2.2.2.6.1. First, mount the set of reference tyres on the vehicle. a0c0
A5  The vehicle accelerates in the starting zone up to 65 ± 2 km/h. a0c0
A5  Activation of the brakes on the track is made always at the same place with a tolerance of 5 meters in longitudinal and 0.5 meters in transverse. a0c0
A5 2.2.2.6.2. According to the type of transmission, two cases are possible: a0c0
A5  (a) Manual transmission a0c0
A5  As soon as the driver is in the measuring zone and having reached 65 ± 2 km/h, the clutch is released and the brake pedal depressed sharply, holding it down as long as necessary to perform the measurement. a0c0
A5  (b)Automatic transmission a0c0
A5  As soon as the driver is in the measuring zone and having reached 65 ± 2 km/h, select neutral gear and then the brake pedal is depressed sharply, holding it down as long as necessary to perform the measurement. a0c0
A5  Automatic activation of the brakes can be performed by means of a detection system made of two parts, one indexed to the track and one embarked on the vehicle. In that case braking is made more rigorously at the same portion of the track. a0c0
A5  If any of the above-mentioned conditions are not met when a measurement is made (speed tolerance, braking time, etc.), the measurement is discarded and a new measurement is made. a0c0
A5 2.2.2.6.3. Test running order a0c0
A5  Examples: a0c0
A5  The run order for a test of 3 sets of candidate tyres (T1 to T3) plus a reference tyre R would be: a0c0
A5  R - T1 - T2 - T3 - R a0c0
A5  The run order for a test of 5 sets of tyres (T1 to T5) plus a reference tyre R would be: a0c0
A5  R - T1 - T2 - T3 - R -T4 - T5 R a0c0
A5 2.2.2.6.4. The direction of the test shall be the same for each set of tests and shall be the same for the candidate test tyre as that used for the SRTT with which its performance is to be compared. a0c0
A5 2.2.2.6.5. For each test and for new tires, the first two braking measurements are discarded. a0c0
A5 2.2.2.6.6. After at least 3 valid measurements have been made in the same direction, the reference tyres are replaced by a set of the candidate tyres (one of the 3 configurations presented in paragraph 2.2.2.2.) and at least 6 valid measurements shall be performed. a0c0
A5 2.2.2.6.7. A maximum of three sets of candidate tyres can be tested before the reference tyre is re-tested. a0c0
A5 2.2.2.7. Processing of measurement results a0c0
A5 2.2.2.7.1. Calculation of the Average Deceleration (AD) a0c0
A5  Each time the measurement is repeated, the average deceleration AD [m/s^2] is calculated by: a0c0
A5  a0c0
A5  Where d [m] is the distance covered between the initial speed Si [m/s] and the final speed Sf [m/s]. a0c0
A5 2.2.2.7.2. Validation of results a0c0
A5  For the reference tyre: a0c0
A5  If the coefficient of variation of "AD" of any two consecutive groups of 3 runs of the reference tyre is higher than 3 per cent, discard all data and repeat the test for all tyres (the candidate tyres and the reference tyre). The coefficient of variation is calculated by the following relation: a0c0
A5  (standard deviation/average)x100 a0c0
A5  For the candidate tyres: a0c0
A5  The coefficients of variation are calculated for all the candidate tyres. a0c0
A5  (standard deviation/average)x100 a0c0
A5  If one coefficient of variation is greater than 3 per cent, discard the data for this candidate tyre and repeat the test. a0c0
A5 2.2.2.7.3. Calculation of the "average AD" a0c0
A5  If R1 is the average of the AD values in the first test of the reference tyre and R2 is the average of the AD values in the second test of the reference tyre, the following operations are performed, according to Table 5. a0c0
A5  Ra is the adjusted average AD of the reference tyre. a0c0
A5  a0c0
A5 2.2.2.7.4. Calculation of braking force coefficient, BFC a0c0
A5  BFC(R) and BFC(T) are calculated according to Table 6: a0c0
A5  a0c0
A5  Ta (a = 1, 2, etc.) is the average of the AD values for a test of a candidate tyre. a0c0
A5 2.2.2.7.5. Calculation of the relative wet grip performance index of the tyre a0c0
A5  The Wet grip index represents the relative performance of the candidate tyre compared to the reference tyre. The way to obtain it depends on the test configuration as defined in paragraph 2.2.2.2. of this annex. The wet grip index of the tyre is calculated as reported into Table 7: a0c0
A5  a0c0
A5  Where: a0c0
A5  "G": centre of gravity of the loaded vehicle a0c0
A5  "m": mass (in kilograms) of the loaded vehicle a0c0
A5  "a": horizontal distance between front axle and centre of gravity of the loaded vehicle (m) a0c0
A5  "b": horizontal distance between rear axle and centre of gravity of the loaded vehicle a0c0
A5  "h": vertical distance between ground level and centre of gravity of the loaded vehicle (m). a0c0
A5  N.B. When "h" is not precisely known, these worst case values shall apply: 1.2 for configuration C2, and 1.5 for configuration C3 a0c0
A5  "g" loaded vehicle acceleration [m/s^2] a0c0
A5  "g" acceleration due to the gravity [m/s^2] a0c0
A5  "X1" longitudinal (X-direction) reaction of the front tyre on the road a0c0
A5  "X2" longitudinal (X-direction) reaction of the rear tyre on the road a0c0
A5  "Z1" normal (Z-direction) reaction of the front tyre on the road a0c0
A5  "Z2" normal (Z-direction) reaction of the rear tyre on the road a0c0
A5  a0c0
A5 2.2.2.8. Wet grip performance comparison between a candidate tyre and a reference tyre using a control tyre a0c0
A5  When the candidate tyre size is significantly different from the reference tyre, a direct comparison on the same vehicle may be not possible. This approach uses an intermediate tyre, hereinafter called the control tyre. a0c0
A5 2.2.2.8.1. The principle lies upon the use of a control tyre and 2 different vehicles for assessing a candidate tyre in comparison with a reference tyre. a0c0
A5  One vehicle can fit the reference tyre and the control tyre, the other the control tyre and the candidate tyre. All conditions are in conformity with paragraphs 2.2.1.2. to 2.2.2.5. above. a0c0
A5 2.2.2.8.2. The first assessment is a comparison between the control tyre and the reference tyre. The result (Wet Grip Index 1) is the relative efficiency of the control tyre compared to the reference tyre. a0c0
A5 2.2.2.8.3. The second assessment is a comparison between the candidate tyre and the control tyre. The result (Wet Grip Index 2) is the relative efficiency of the candidate tyre compared to the control tyre. a0c0
A5  The second assessment is done on the same track as the first one and within one week maximum. The wetted surface temperature shall be in the range of ± 5 °C of the temperature of the first assessment. The control tyre set (4 or 6 tyres) is physically the same set as the set used for the first assessment. a0c0
A5 2.2.2.8.4. The wet grip index of the candidate tyre compared to the reference tyre is deduced by multiplying the relative efficiencies calculated above: a0c0
A5  (Wet Grip Index 1 ⋅ Wet Grip Index 2) a0c0
A5  Note: When the test expert decides to use an SRTT tyre as a control tyre (i.e. in the test procedure two SRTTs are compared directly instead of an SRTT with a control tyre) the result of the comparison between the SRTTs is called the "local shift factor". a0c0
A5  It is permitted to use a previous SRTTs comparison. a0c0
A5  The comparison results shall be checked periodically. a0c0
A5 2.2.2.8.5. Selection of a set of tyres as a control tyre set a0c0
A5  A "control tyre" set is a group of identical tyres made in the same factory during a one week period. a0c0
A5 2.2.2.8.6. Reference and control tyres a0c0
A5  Before the first assessment (control tyre / reference tyre), normal storage conditions can be used. It is necessary that all the tyres of a control tyre set have been stored in the same conditions. a0c0
A5 2.2.2.8.7. Storage of control tyres a0c0
A5  As soon as the control tyre set has been assessed in comparison with the reference tyre, specific storage conditions shall be applied for control tyres replacement. a0c0
A5 2.2.2.8.8. Replacement of reference and control tyres a0c0
A5  When irregular wear or damage results from tests, or when wear influences the test results, the use of the tyre shall be discontinued. a0c0
A5  Annex 5 – Appendix 1 a0c0
A5  Test reports examples of wet grip index a0c0
A5  a0c0
A5  a0c0
A6  Annex 6 a0c0
A6  Test procedure for measuring rolling resistance a0c0
A6 1. Test methods a0c0
A6  The alternative measurement methods listed below are given in this Regulation. The choice of an individual method is left to the tester. For each method, the test measurements shall be converted to a force acting at the tyre/drum interface. The measured parameters are: a0c0
A6  (a) In the force method: the reaction force measured or converted at the tyre spindle;[1] a0c0
A6 [1] This measured value also includes the bearing and aerodynamic losses of the wheel and tyre which are also to be considered for further data interpretation. a0c0
A6  (b) In the torque method: the torque input measured at the test drum;[2] a0c0
A6  (c) In the deceleration method: the measurement of deceleration of the test drum and tyre assembly;[2] a0c0
A6  (d) In the power method: the measurement of the power input to the test drum.[2] a0c0
A6 [2] The measured value in the torque, deceleration and power methods also includes the bearing and aerodynamic losses of the wheel, the tyre, and the drum which are also to be considered for further data interpretation. a0c0
A6 2. Test equipment a0c0
A6 2.1. Drum specifications a0c0
A6 2.1.1. Diameter a0c0
A6  The test dynamometer shall have a cylindrical flywheel (drum) with a diameter of at least 1.7 m. a0c0
A6  The Fr and Cr values shall be expressed relative to a drum diameter of 2.0 m. If drum diameter different than 2.0 m is used, a correlation adjustment shall be made following the method in paragraph 6.3. of this annex. a0c0
A6 2.1.2. Surface a0c0
A6  The surface of the drum shall be smooth steel. Alternatively, in order to improve skim test reading accuracy, a textured surface may also be used, which should be kept clean. a0c0
A6  The Fr and Cr values shall be expressed relative to the "smooth" drum surface. If a textured drum surface is used, see Appendix 1, paragraph 7. a0c0
A6 2.1.3. Width a0c0
A6  The width of the drum test surface shall exceed the width of the test tyre contact patch. a0c0
A6 2.2. Measuring rim (see Appendix 2) a0c0
A6  The tyre shall be mounted on a steel or light alloy measuring rim, as follows: a0c0
A6  (a) For Class C1 tyres, the width of the rim shall be as defined in ISO 4000-1:2010, a0c0
A6  (b) For Class C2 and C3 tyres, the width of the rim shall be as defined in ISO 4209 1:2001. a0c0
A6  In cases where the width is not defined in the above mentioned ISO Standards, the rim width as defined by one of the standards organizations as specified in Appendix 4 may be used. a0c0
A6 2.3. Load, alignment, control and instrumentation accuracies a0c0
A6  Measurement of these parameters shall be sufficiently accurate and precise to provide the required test data. The specific and respective values are shown in Appendix 1. a0c0
A6 2.4. Thermal environment a0c0
A6 2.4.1. Reference conditions a0c0
A6  The reference ambient temperature, measured at a distance not less than 0.15 m and not more than 1 m from the tyre sidewall, shall be 25 °C. a0c0
A6 2.4.2. Alternative conditions a0c0
A6  If the test ambient temperature is different from the reference ambient temperature, the rolling resistance measurement shall be corrected to the reference ambient temperature in accordance with paragraph 6.2. of this annex. a0c0
A6 2.4.3. Drum surface temperature. a0c0
A6  Care should be taken to ensure that the temperature of the test drum surface is the same as the ambient temperature at the beginning of the test. a0c0
A6 3. Test conditions a0c0
A6 3.1. General a0c0
A6  The test consists of a measurement of rolling resistance in which the tyre is inflated and the inflation pressure allowed to build up, i.e., "capped air". a0c0
A6 3.2. Test speeds a0c0
A6  The value shall be obtained at the appropriate drum speed specified in Table 1. a0c0
A6  a0c0
A6 3.3. Test load a0c0
A6  The standard test load shall be computed from the values shown in Table 2 and shall be kept within the tolerance specified in Appendix 1. a0c0
A6 3.4. Test inflation pressure a0c0
A6  The inflation pressure shall be in accordance with that shown in Table 2 and shall be capped with the accuracy specified in paragraph 4. of Appendix 1 to this annex. a0c0
A6  a0c0
A6 Note: The inflation pressure shall be capped with the accuracy specified in paragraph 4. Of Appendix 1 to this annex. a0c0
A6 (a) For those passenger car tyres belonging to categories which are not shown in ISO 4000-1:2010, the inflation pressure shall be the inflation pressure recommended by the tyre manufacturer, corresponding to the maximum tyre load capacity, reduced by 30 kPa. a0c0
A6 (b) As a percentage of single load, or 85 per cent of maximum load capacity for single application specified in applicable tyre standards manuals if not marked on tyre. a0c0
A6 (c) Inflation pressure marked on sidewall, or if not marked on sidewall, as specified in applicable tyre standards manuals corresponding to maximum load capacity for single application. a0c0
A6 3.5. Duration and speed. a0c0
A6  When the deceleration method is selected, the following requirements apply: a0c0
A6  (a) The deceleration j shall be determined in differential dω/dt or discrete Δω/Δt form, where ω is angular velocity, t - time; a0c0
A6  If the differential form dω/dt is used, then the recommendations of Appendix 5 to this annex are to be applied. a0c0
A6  (b) For duration Δt, the time increments shall not exceed 0.5 s; a0c0
A6  (c) Any variation of the test drum speed shall not exceed 1 km/h within one time increment. a0c0
A6 4. Test procedure a0c0
A6 4.1. General a0c0
A6  The test procedure steps described below shall be followed in the sequence given. a0c0
A6 4.2. Thermal conditioning a0c0
A6  The inflated tyre shall be placed in the thermal environment of the test location for a minimum of: a0c0
A6  (a) 3 hours for Class C1 tyres; a0c0
A6  (b) 6 hours for Class C2 and C3 tyres. a0c0
A6 4.3. Pressure adjustment a0c0
A6  After thermal conditioning, the inflation pressure shall be adjusted to the test pressure, and verified 10 minutes after the adjustment is made. a0c0
A6 4.4. Warm-up a0c0
A6  The warm-up durations shall be as specified in Table 3. a0c0
A6  a0c0
A6 4.5. Measurement and recording a0c0
A6  The following shall be measured and recorded (see Figure 1): a0c0
A6  (a) Test speed Un; a0c0
A6  (b) Load on the tyre normal to the drum surface Lm; a0c0
A6  (c) The initial test inflation pressure as defined in paragraph 3.3. above; a0c0
A6  (d) The coefficient of rolling resistance measured Cr, and its corrected value Crc, at 25 °C and for a drum diameter of 2 m; a0c0
A6  (e) The distance from the tyre axis to the drum outer surface under steady state rL,; a0c0
A6  (f) Ambient temperature tamb; a0c0
A6  (g) Test drum radius R; a0c0
A6  (h) Test method chosen; a0c0
A6  (i) Test rim (size and material); a0c0
A6  (j) Tyre size, manufacturer, type, identity number (if one exists), speed symbol, load index, DOT number (Department of Transportation). a0c0
A6  a0c0
A6  All the mechanical quantities (forces, torques) will be orientated in accordance with the axis systems specified in ISO 8855:1991. a0c0
A6  The directional tyres shall be run in their specified rotation sense. a0c0
A6 4.6. Measurement of parasitic losses a0c0
A6  The parasitic losses shall be determined by one of the following procedures given in paragraph 4.6.1. or 4.6.2. below. a0c0
A6 4.6.1. Skim test reading a0c0
A6  Skim test reading follows the procedure below: a0c0
A6  (a) Reduce the load to maintain the tyre at the test speed without slippage.[3] a0c0
A6  The load values should be as follows: a0c0
A6  (i) Class C1 tyres: recommended value of 100 N; not to exceed 200 N; a0c0
A6  (ii) Class C2 tyres: recommended value of 150 N; not to exceed 200 N for machines designed for Class C1 tyre measurement or 500 N for machine designed for Class C2 and C3 tyres; a0c0
A6  (iii) Class C3 tyres: recommended value of 400 N; not to exceed 500 N. a0c0
A6  (b) Record the spindle force Ft, input torque Tt, or the power, whichever applies;[3] a0c0
A6  (c) Record the load on the tyre normal to the drum surface Lm[3]. a0c0
A6 [3] With the exception of the force method, the measured value includes the bearing and aerodynamic losses of the wheel, the tyre, and the drum losses which also need to be considered. a0c0
A6  It is known that the spindle and drum bearing frictions depend on the applied load. Consequently, it is different for the loaded system measurement and the skim test reading. However, for practical reasons, this difference can be disregarded. a0c0
A6 4.6.2. Deceleration method a0c0
A6  The deceleration method follows the procedure below: a0c0
A6  (a) Remove the tyre from the test surface; a0c0
A6  (b) Record the deceleration of the test drum ΔωDo/ Δt and that of the unloaded tyre ΔωT0/ Δt or record the deceleration of the test drum jD0 and that of the unloaded tyre jT0 in exact or approximate form in accordance with paragraph 3.5. above. a0c0
A6 4.7. Allowance for machines exceeding σm criterion a0c0
A6  The steps described in paragraphs 4.3. to 4.5. above shall be carried out once only, if the measurement standard deviation determined in accordance with paragraph 6.5. below is: a0c0
A6  (a) Not greater than 0.075 N/kN for Class C1 and C2 tyres; a0c0
A6  (b) Not greater than 0.06 N/kN for Class C3 tyres. a0c0
A6  If the measurement standard deviation exceeds this criterion, the measurement process will be repeated n times as described in paragraph 6.5. below. The rolling resistance value reported shall be the average of the n measurements. a0c0
A6 5. Data interpretation a0c0
A6 5.1. Determination of parasitic losses a0c0
A6 5.1.1. General a0c0
A6  The laboratory shall perform the measurements described in paragraph 4.6.1. above for the force, torque and power methods or those described in paragraph 4.6.2. above for the deceleration method, in order to determine precisely in the test conditions (load, speed, temperature) the tyre spindle friction, the tyre and wheel aerodynamic losses, the drum (and as appropriate, engine and/or clutch) bearing friction, and the drum aerodynamic losses. a0c0
A6  The parasitic losses related to the tyre/drum interface Fpl expressed in newton shall be calculated from the force Ft torque, power or the deceleration, as shown in paragraphs 5.1.2. to 5.1.5. below. a0c0
A6 5.1.2. Force method at tyre spindle a0c0
A6  a0c0
A6  Where: a0c0
A6  Ft is the tyre spindle force in newton (see paragraph 4.6.1. above), a0c0
A6  rL is the distance from the tyre axis to the drum outer surface under steady state conditions, in meter, a0c0
A6  R is the test drum radius, in meter. a0c0
A6 5.1.3. Torque method at drum axis a0c0
A6  a0c0
A6  Where: a0c0
A6  Tt is the input torque in newton meter, as determined in paragraph 4.6.1, a0c0
A6  R is the test drum radius, in meter. a0c0
A6 5.1.4. Power method at drum axis a0c0
A6  a0c0
A6  Where: a0c0
A6  V is the electrical potential applied to the machine drive, in volt, a0c0
A6  A is the electric current drawn by the machine drive, in ampere, a0c0
A6  Un is the test drum speed, in kilometer per hour. a0c0
A6 5.1.5. Deceleration method a0c0
A6  a0c0
A6  Where: a0c0
A6  ID is the test drum inertia in rotation, in kilogram meter squared, a0c0
A6  R is the test drum surface radius, in meter, a0c0
A6  ωD0 is the test drum angular speed, without tyre, in radians per second, a0c0
A6  Δt0 is the time increment chosen for the measurement of the parasitic losses without tyre, in second, a0c0
A6  IT is the spindle, tyre and wheel inertia in rotation, in kilogram meter squared, a0c0
A6  Rr is the tyre rolling radius, in meter, a0c0
A6  ωT0 is the tyre angular speed, unloaded tyre, in radian per second. a0c0
A6  or a0c0
A6  a0c0
A6  Where: a0c0
A6  ID is the test drum inertia in rotation, in kilogram meter squared, a0c0
A6  R is the test drum surface radius, in meter, a0c0
A6  jD0 is the deceleration of the test drum, without tyre, in radians per second squared, a0c0
A6  IT is the spindle, tyre and wheel inertia in rotation, in kilogram meter squared, a0c0
A6  Rr is the tyre rolling radius, in meter, a0c0
A6  jT0 is the deceleration of unloaded tyre, in radians per second squared. a0c0
A6 5.2. Rolling resistance calculation a0c0
A6 5.2.1. General a0c0
A6  The rolling resistance Fr, expressed in newton, is calculated using the values obtained by testing the tyre to the conditions specified in this international standard and by subtracting the appropriate parasitic losses Fpl, obtained according to paragraph 5.1. above. a0c0
A6 5.2.2. Force method at tyre spindle a0c0
A6  The rolling resistance Fr, in newton, is calculated using the equation a0c0
A6  a0c0
A6  Where: a0c0
A6  Ft is the tyre spindle force in newton, a0c0
A6  Fpl represents the parasitic losses as calculated in paragraph 5.1.2. above, a0c0
A6  rL is the distance from the tyre axis to the drum outer surface under steady-state conditions, in meter, a0c0
A6  R is the test drum radius, in meter. a0c0
A6 5.2.3. Torque method at drum axis a0c0
A6  The rolling resistance Fr, in newton, is calculated with the equation a0c0
A6  a0c0
A6  Where: a0c0
A6  Tt is the input torque, in newton meter, a0c0
A6  Fpl represents the parasitic losses as calculated in paragraph 5.1.3. above, a0c0
A6  R is the test drum radius, in meter. a0c0
A6 5.2.4. Power method at drum axis a0c0
A6  The rolling resistance Fr, in newton, is calculated with the equation: a0c0
A6  a0c0
A6  Where: a0c0
A6  V = is the electrical potential applied to the machine drive, in volt, a0c0
A6  A = is the electric current drawn by the machine drive, in ampere, a0c0
A6  Un = is the test drum speed, in kilometer per hour, a0c0
A6  Fpl = represents the parasitic losses as calculated in paragraph 5.1.4. above. a0c0
A6 5.2.5. Deceleration method a0c0
A6  The rolling resistance Fr, in newton, is calculated using the equation: a0c0
A6  a0c0
A6  Where: a0c0
A6  ID is the test drum inertia in rotation, in kilogram meter squared, a0c0
A6  R is the test drum surface radius, in meter, a0c0
A6  Fpl represents the parasitic losses as calculated in paragraph 5.1.5. above, a0c0
A6  Δtv is the time increment chosen for measurement, in second, a0c0
A6  Δωv is the test drum angular speed increment, without tyre, in radian per second, a0c0
A6  IT is the spindle, tyre and wheel inertia in rotation, in kilogram meter squared, a0c0
A6  Rr is the tyre rolling radius, in meter, a0c0
A6  Fr is the rolling resistance, in newton. a0c0
A6  or a0c0
A6  a0c0
A6  Where: a0c0
A6  ID is the test drum inertia in rotation, in kilogram meter squared, a0c0
A6  R is the test drum surface radius, in meter, a0c0
A6  Fpl represents the parasitic losses as calculated in paragraph 5.1.5. above, a0c0
A6  jV is the deceleration of the test drum, in radians per second squared, a0c0
A6  IT is the spindle, tyre and wheel inertia in rotation, in kilogram meter squared, a0c0
A6  Rr is the tyre rolling radius, in meter, a0c0
A6  Fr is the rolling resistance, in newton. a0c0
A6 6. Data analysis a0c0
A6 6.1. Rolling resistance coefficient a0c0
A6  The rolling resistance coefficient Cr is calculated by dividing the rolling resistance by the load on the tyre: a0c0
A6  a0c0
A6  Where: a0c0
A6  Fr is the rolling resistance, in newton, a0c0
A6  Lm is the test load, in kN. a0c0
A6 6.2. Temperature correction a0c0
A6  If measurements at temperatures other than 25 °C are unavoidable (only temperatures not less than 20 °C or more than 30 °C are acceptable), then a correction for temperature shall be made using the following equation, with: a0c0
A6  Fr25 is the rolling resistance at 25 °C, in Newton: a0c0
A6  a0c0
A6  Where: a0c0
A6  Fr is the rolling resistance, in Newton, a0c0
A6  tamb is the ambient temperature, in degree Celsius, a0c0
A6  K is equal to: a0c0
A6  0.008 for Class C1 tyres a0c0
A6  0.010 for Class C2 and C3 tyres with a load index equal or lower than 121 a0c0
A6  0.006 for Class C3 tyres with a load index greater than 121 a0c0
A6 6.3. Drum diameter correction a0c0
A6  Test results obtained from different drum diameters shall be compared by using the following theoretical formula: a0c0
A6  a0c0
A6  Where: a0c0
A6  R1 is the radius of drum 1, in meter, a0c0
A6  R2 is the radius of drum 2, in meter, a0c0
A6  rT is one-half of the nominal design tyre diameter, in meter, a0c0
A6  Fr01 is the rolling resistance value measured on drum 1, in newton, a0c0
A6  Fr02 is the rolling resistance value measured on drum 2, in newton. a0c0
A6 6.4. Measurement result a0c0
A6  Where n measurements are greater than 1, if required by paragraph 4.6. above, the measurement result shall be the average of the Cr values obtained for the n measurements, after the corrections described in paragraphs 6.2. and 6.3. above have been made. a0c0
A6 6.5. The laboratory shall ensure that, based on a minimum of three measurements, the machine maintains the following values of σm, as measured on a single tyre: a0c0
A6  σm ≤ 0.075 N/kN for tyres of Classes C1 and C2 a0c0
A6  σm ≤ 0.06 N/kN for tyres of Class C3 a0c0
A6  If the above requirement for σm is not met, the following formula shall be applied to determine the minimum number of measurements n (rounded to the immediate superior integer value) that are required by the machine to qualify for conformance with this Regulation. a0c0
A6  n = (σm/ x)^2 a0c0
A6  Where: a0c0
A6  x = 0.075 N/kN for tyres of Classes C1 and C2 a0c0
A6  x = 0.06 N/kN for tyres of Class C3 a0c0
A6  If a tyre needs to be measured several times, the tyre/wheel assembly shall be removed from the machine between the successive measurements. a0c0
A6  If the removal/refitting operation duration is less than 10 minutes, the warm-up durations indicated in paragraph 4.3. above may be reduced to: a0c0
A6  (a) 10 minutes for tyres of Class C1; a0c0
A6  (b) 20 minutes for tyres of Class C2; a0c0
A6  (c) 30 minutes for tyres of Class C3. a0c0
A6 6.6. Monitoring of the laboratory control tyre shall be carried out at intervals no greater than one month. Monitoring shall include a minimum of 3 separate measurements taken during this one month period. The average of the 3 measurements taken during a given one-month period shall be evaluated for drift from one monthly evaluation to another. a0c0
A6  Annex 6 – Appendix 1 a0c0
A6  Test equipment tolerances a0c0
A6 1. Purpose a0c0
A6  The limits specified in this annex are necessary in order to achieve suitable levels of repeatable test results, which can also be correlated among various test laboratories. These tolerances are not meant to represent a complete set of engineering specifications for test equipment; rather, they should serve as guidelines for achieving reliable test results. a0c0
A6 2. Test rims a0c0
A6 2.1. Width a0c0
A6  For passenger car tyre rims (C1 tyres), the test rim width shall be the same as the measuring rim determined in ISO 4000-1: 2010, clause 6.2.2. a0c0
A6  For truck and bus tyres (C2 and C3), the rim width shall be the same as the measuring rim determined in ISO 4209-1:2001, clause 5.1.3. a0c0
A6  In cases where the width is not defined in the above mentioned ISO Standards, the rim width as defined by one of the standards organizations as specified in Appendix 4 to Annex 6 may be used. a0c0
A6 2.2. Run-out a0c0
A6  Run-out shall meet the following criteria: a0c0
A6  (a) Maximum radial run-out: 0.5 mm; a0c0
A6  (b) Maximum lateral run-out: 0.5 mm. a0c0
A6 3. Drum / tyre alignment a0c0
A6  General: a0c0
A6  Angle deviations are critical to the test results. a0c0
A6 3.1. Load application a0c0
A6  The direction of tyre loading application shall be kept normal to the test surface and shall pass through the wheel centre within a0c0
A6  (a) 1 mrad for the force and deceleration methods; a0c0
A6  (b) 5 mrad for the torque and power methods. a0c0
A6 3.2. Tyre alignment a0c0
A6 3.2.1. Camber angle a0c0
A6  The plane of the wheel shall be perpendicular to the test surface within 2 mrad for all methods. a0c0
A6 3.2.2. Slip angle a0c0
A6  The plane of the tyre shall be parallel to the direction of the test surface motion within 1 mrad for all methods. a0c0
A6 4. Control accuracy a0c0
A6  Test conditions shall be maintained at their specified values, independent of perturbations induced by the tyre and rim non-uniformity, such that the overall variability of the rolling resistance measurement is minimized. In order to meet this requirement, the average value of measurements taken during the rolling resistance data collection period shall be within the accuracies stated as follows: a0c0
A6  (a) Tyre loading: a0c0
A6  (i) For LI ≤ 121 ± 20 N or ± 0.5 per cent, whichever is greater; a0c0
A6  (ii) For LI > 121 ± 45 N or ± 0.5 per cent whichever is greater; a0c0
A6  (b) Cold inflation pressure: ± 3 kPa; a0c0
A6  (c) Surface speed: a0c0
A6  (i) ± 0.2 km/h for the power, torque and deceleration methods; a0c0
A6  (ii) ± 0.5 km/h for the force method; a0c0
A6  (d) Time: a0c0
A6  (i) ± 0.02 s for the time increments specified in Annex 6, paragraph 3.5.(b) for the data acquisition in the deceleration method in Δω/Δt form; a0c0
A6  (ii) ± 0.2 per cent for the time increments specified in Annex 6, paragraph 3.5.(a) for the data acquisition in the deceleration method in dω/dt form; a0c0
A6  (iii) ± 5 per cent for the other time durations specified in Annex 6. a0c0
A6 5. Instrumentation accuracy a0c0
A6  The instrumentation used for readout and recording of test data shall be accurate within the tolerances stated below: a0c0
A6  a0c0
A6 6. Compensation for load/spindle force interaction and load misalignment for the force method only a0c0
A6  Compensation of both load/spindle force interaction ("cross talk") and load misalignment may be achieved either by recording the spindle force for both forward and reverse tyre rotation or by dynamic machine calibration. If spindle force is recorded for forward and reverse directions (at each test condition), compensation is achieved by subtracting the "reverse" value from the "forward" value and dividing the result by two. If dynamic machine calibration is intended, the compensation terms may be easily incorporated in the data reduction. a0c0
A6  In cases where reverse tyre rotation immediately follows the completion of the forward tyre rotation, a warm-up time for reverse tyre rotation shall be at least 10 minutes for Class C1 tyres and 30 minutes for all other tyre types. a0c0
A6 7. Test surface roughness a0c0
A6  The roughness, measured laterally, of the smooth steel drum surface shall have a maximum centreline average height value of 6.3 μm. a0c0
A6  Note: In cases where a textured drum surface is used instead of a smooth steel surface, this fact is noted in the test report. The surface texture shall then be 180 μm deep (80 grit) and the laboratory is responsible for maintaining the surface roughness characteristics. No specific correction factor is recommended for cases where a textured drum surface is used. a0c0
A6  Annex 6 – Appendix 2 a0c0
A6  Measuring rim width a0c0
A6 1. Class C1 tyres a0c0
A6  The measuring rim width Rm is equal to the product of the nominal section width SN and the coefficient K2: a0c0
A6  Rm = K2 x SN a0c0
A6  rounded to the nearest standardized rim, where K2 is the rim/section width ratio coefficient. For tyres mounted on 5° drop-centre rims with a nominal diameter expressed by a two-figure code: a0c0
A6  K2 = 0.7 for nominal aspect ratios 95 to 75 a0c0
A6  K2= 0.75 for nominal aspect ratios 70 to 60 a0c0
A6  K2 = 0.8 for nominal aspect ratios 55 and 50 a0c0
A6  K2 = 0.85 for nominal aspect ratio 45 a0c0
A6  K2 = 0.9 for nominal aspect ratios 40 to 30 a0c0
A6  K2 = 0.92 for nominal aspect ratios 20 and 25 a0c0
A6 2. Class C2 and C3 tyres a0c0
A6  The measuring rim width Rm is equal to the product of the nominal section width SN, and the coefficient K4: a0c0
A6  Rm = K4 x SN rounded to the nearest standardized rim width. a0c0
A6  a0c0
A6  Annex 6 – Appendix 3 a0c0
A6  Test report and test data (Rolling resistance) a0c0
A6  Part 1: Report a0c0
A6 1. Type Approval Authority or Technical Service: a0c0
A6 2. Name and address of applicant: a0c0
A6 3. Test report No.: a0c0
A6 4. Manufacturer and brand name or trade description: a0c0
A6 5. Tyre class (C1, C2 or C3): a0c0
A6 6. Category of use: a0c0
A6 7. Rolling resistance coefficient a0c0
A6  (temperature and drum diameter corrected): a0c0
A6 8. Comments (if any): a0c0
A6 9. Date: a0c0
A6 10. Signature: a0c0
A6  Part 2: Test data a0c0
A6 1. Date of test: a0c0
A6 2. Test machine identification and drum diameter/surface: a0c0
A6 3. Test tyre details: a0c0
A6 3.1. Tyre size designation and service description: a0c0
A6 3.2. Tyre brand and trade description: a0c0
A6 3.3. Reference inflation pressure: [kPa] a0c0
A6 4. Test data: a0c0
A6 4.1. Measurement method: a0c0
A6 4.2. Test speed: [km/h] a0c0
A6 4.3. Load: [N] a0c0
A6 4.4. Test inflation pressure, initial: [kPa] a0c0
A6 4.5. Distance from the tyre axis to the drum outer surface under steady state conditions, rL: [m] a0c0
A6 4.6. Test rim width and material: a0c0
A6 4.7. Ambient temperature: [°C] a0c0
A6 4.8. Skim test load (except deceleration method): [N] a0c0
A6 5. Rolling resistance coefficient: a0c0
A6 5.1. Initial value (or average in the case of more than 1): [N/kN] a0c0
A6 5.2. Temperature corrected: [N/kN] a0c0
A6 5.3. Temperature and drum diameter corrected: [N/kN] a0c0
A6  Annex 6 – Appendix 4 a0c0
A6  Tyre standards organizations a0c0
A6 1. The Tire and Rim Association, Inc. (TRA) a0c0
A6 2. The European Tyre and Rim Technical Organisation (ETRTO) a0c0
A6 3. The Japan Automobile Tyre Manufacturers Association (JATMA) a0c0
A6 4. The Tyre and Rim Association of Australia (TRAA) a0c0
A6 5. South Africa Bureau of Standards (SABS) a0c0
A6 6. China Association for Standardization (CAS) a0c0
A6 7. Indian Tyre Technical Advisory Committee (ITTAC) a0c0
A6 8. International Standards Organisation (ISO) a0c0
A6  Annex 6 – Appendix 5 a0c0
A6  Deceleration method: Measurements and data processing for deceleration value obtaining in differential form d /dt. a0c0
A6 1. Record dependency "distance-time" of rotating body decelerated from peripheral with a speed range such as 82 to 78 km/h or 62 to 58 km/h dependent on tyre class (Annex 6, paragraph 3.2., Table 1) in a discrete form (Figure 1) for a rotating body: a0c0
A6  z = f(tz) a0c0
A6  Where: a0c0
A6  z is a number of body revolutions during deceleration; a0c0
A6  tz is end time of revolution number z in seconds recorded with 6 digits after zero. a0c0
A6  a0c0
A6  Note 1: The lower speed of the recording range may be reduced down to 60 km/h when test speed is 80 km/h and 40 km/h when the test speed is 60 km/h. a0c0
A6 2. Approximate recorded dependency by continuous, monotonic, differentiable function: a0c0
A6 2.1. Choose the value nearest to the maximum of z dividable by 4 and divide it into 4 equal parts with bounds: 0, z1(t1), z2(t2), z3(t3), z4(t4). a0c0
A6 2.2. Work out the system for 4 equations each of the form: a0c0
A6  a0c0
A6  Where unknowns: a0c0
A6  A is a dimensionless constant, a0c0
A6  B is a constant in revolutions per second, a0c0
A6  T is a constant in seconds, a0c0
A6  m is the number of bounds shown in figure 1. a0c0
A6  Insert in these 4 equations the coordinates of 4-th bound above. a0c0
A6 2.3. Take constants A, B and T as the solution of the equation system of paragraph 2.2. above using iteration process and approximate measured data by formulae: a0c0
A6  a0c0
A6  Where: a0c0
A6  z(t) is the current continuous angular distance in number of revolutions (not only integer values); a0c0
A6  t is time in seconds. a0c0
A6  Note 2: Other approximating functions z = f(tz) may be used if their adequacy is proven. a0c0
A6 3. Calculate the deceleration j in revolutions per second squared (s-2) by the formula: a0c0
A6  a0c0
A6  Where: a0c0
A6  ω is the angular speed in revolutions per second (1/s). a0c0
A6  For the case Un = 80 km/h; ω = 22.222/Rr (or R). a0c0
A6  For the case Un = 60 km/h; ω = 16.666/Rr (or R). a0c0
A6 4. Estimate the quality of approximation of measured data and its accuracy by parameters: a0c0
A6 4.1. Standard deviation in percentages: a0c0
A6  a0c0
A6 4.2. Coefficient of determination a0c0
A6  a0c0
A6  Where: a0c0
A6  a0c0
A6  Note 3: The above calculations for this variant of the deceleration method for tyre rolling resistance measurement can be executed by the computer program "Deceleration Calculator" downloadable from the WP.29 website[1] as well as any software which allows the calculation of nonlinear regression. a0c0
A6 [1] http://www.unece.org/trans/main/wp29/wp29wgs/wp29gen/deceleration_calculator.html. a0c0
A7  Annex 7 a0c0
A7  Procedures for snow performance testing relative to snow tyre for use in severe snow conditions a0c0
A7 1. Specific definitions for snow test when different from existing ones a0c0
A7 1.1. "Test run" means a single pass of a loaded tyre over a given test surface. a0c0
A7 1.2. "Braking test" means a series of a specified number of ABS-braking test runs of the same tyre repeated within a short time frame. a0c0
A7 1.3. "Traction test" means a series of a specified number of spin-traction test runs according to ASTM standard F1805-06 of the same tyre repeated within a short time frame. a0c0
A7 1.4. "Acceleration test" means a series of specified number of traction controlled acceleration test runs of the same tyre repeated within a short timeframe. a0c0
A7 2. Spin traction method for Class C1 and C2 tyres (traction force test per paragraph 6.4. (b) of this Regulation) a0c0
A7  The test procedure of ASTM standard F1805-06 shall be used to assess snow performance through spin traction values on medium packed snow (The snow compaction index measured with a CTI penetrometer[1] shall be between 70 and 80). a0c0
A7 [1] See appendix of ASTM standard F1805-06 for details. a0c0
A7 2.1. The test course surface shall be composed of a medium packed snow surface, as characterized in table A2.1 of ASTM standard F1805-06. a0c0
A7 2.2. The tyre load for testing shall be as per option 2 in paragraph 11.9.2. of ASTM standard F1805-06. a0c0
A7 3. Braking on snow method for Class C1 and C2 tyres a0c0
A7 3.1. General conditions a0c0
A7 3.1.1. Test course a0c0
A7  The braking tests shall be done on a flat test surface of sufficient length and width, with a maximum 2 per cent gradient, covered with packed snow. a0c0
A7  The snow surface shall be composed of a hard packed snow base at least 3 cm thick and a surface layer of medium packed and prepared snow about 2 cm thick. a0c0
A7  The air temperature, measured about one meter above the ground, shall be between -2 °C and -15 °C; the snow temperature, measured at a depth of about one centimeter, shall be between -4 °C and -15 °C. a0c0
A7  It is recommended to avoid direct sunlight, large variations of sunlight or humidity, as well as wind. a0c0
A7  The snow compaction index measured with a CTI penetrometer1 shall be between 75 and 85. a0c0
A7 3.1.2. Vehicle a0c0
A7  The test shall be conducted with a standard production vehicle in good running order and equipped with an ABS system. a0c0
A7  The vehicle used shall be such that the loads on each wheel are appropriate to the tyres being tested. Several different tyre sizes can be tested on the same vehicle. a0c0
A7 3.1.3. Tyres a0c0
A7  The tyres should be "broken-in" prior to testing to remove spew, compound nodules or flashes resulting from the moulding process. The tyre surface in contact with snow shall be cleaned before performing a test. a0c0
A7  Tyres shall be conditioned at the outdoor ambient temperature at least two hours before their mounting for tests. Tyre pressures shall then be adjusted to the values specified for the test. a0c0
A7  In case a vehicle cannot accommodate both the reference and candidate tyres, a third tyre ("control" tyre) may be used as an intermediate. First test control vs. reference on another vehicle, then test candidate vs. control on the vehicle. a0c0
A7 3.1.4. Load and pressure a0c0
A7 3.1.4.1. For C1 tyres, the vehicle load shall be such that the resulting loads on the tyres are between 60 per cent and 90 per cent of the load corresponding to the tyre load index. a0c0
A7  The cold inflation pressure shall be 240 kPa. a0c0
A7 3.1.4.2. For C2 tyres, the vehicle load shall be such that the resulting loads on the a0c0
A7  tyres are between 60 per cent and 100 per cent of the load corresponding to the tyre load index. a0c0
A7  The static tyre load on the same axle should not differ by more than 10 per cent. a0c0
A7  The inflation pressure is calculated to run at constant deflection: a0c0
A7  For a vertical load higher or equal to 75 per cent of the load capacity of the tyre, a constant deflection is applied, hence the test inflation pressure "Pt" shall be calculated as follows: a0c0
A7  a0c0
A7  Qr is the maximum load associated to the load capacity index of the tyre written on the sidewall a0c0
A7  Pr is the reference pressure corresponding to the maximum load capacity Qr a0c0
A7  Qt is the static test load of the tyre a0c0
A7  For a vertical load lower than 75 per cent of the load capacity of the tyre, a constant inflation pressure is applied, hence the test inflation pressure Pt shall be calculated as follows: a0c0
A7  a0c0
A7  Pr is the reference pressure corresponding to the maximum load capacity Qr a0c0
A7  Check the tyre pressure just prior to testing at ambient temperature. a0c0
A7 3.1.5. Instrumentation a0c0
A7  The vehicle shall be fitted with calibrated sensors suitable for measurements in winter. There shall be a data acquisition system to store measurements. a0c0
A7  The accuracy of measurement sensors and systems shall be such that the relative uncertainty of the measured or computed mean fully developed decelerations is less than 1 per cent. a0c0
A7 3.2. Testing sequences a0c0
A7 3.2.1. For every candidate tyre and the standard reference tyre, ABS-braking test runs shall be repeated a minimum of 6 times. a0c0
A7  The zones where ABS-braking is fully applied shall not overlap. a0c0
A7  When a new set of tyres is tested, the runs are performed after shifting aside the vehicle trajectory in order not to brake on the tracks of the previous tyre. a0c0
A7  When it is no longer possible not to overlap full ABS-braking zones, the test course shall be re-groomed. a0c0
A7  Required sequence: a0c0
A7  6 repeats SRTT, then shift aside to test next tyre on fresh surface a0c0
A7  6 repeats Candidate 1, then shift aside a0c0
A7  6 repeats Candidate 2, then shift aside a0c0
A7  6 repeats SRTT, then shift aside a0c0
A7 3.2.2. Order of testing: a0c0
A7  If only one candidate tyre is to be evaluated, the order of testing shall be: a0c0
A7  R1 - T - R2 a0c0
A7  Where: a0c0
A7  R1 is the initial test of the SRTT, R2 is the repeat test of the SRTT and T is the test of the candidate tyre to be evaluated. a0c0
A7  A maximum of two candidate tyres may be tested before repeating the SRTT test, for example: a0c0
A7  R1 - T1 - T2 - R2. a0c0
A7 3.2.3. The comparative tests of SRTT and candidate tyres shall be repeated on two different days. a0c0
A7 3.3. Test procedure a0c0
A7 3.3.1. Drive the vehicle at a speed not lower than 28 km/h. a0c0
A7 3.3.2. When the measuring zone has been reached, the vehicle gear is set into neutral, the brake pedal is depressed sharply by a constant force sufficient to cause operation of the ABS on all wheels of the vehicle and to result in stable deceleration of the vehicle and held down until the speed is lower than 8 km/h. a0c0
A7 3.3.3. The mean fully developed deceleration between 25 km/h and 10 km/h shall be computed from time, distance, speed, or acceleration measurements. a0c0
A7 3.4. Data evaluation and presentation of results a0c0
A7 3.4.1. Parameters to be reported a0c0
A7 3.4.1.1. For each tyre and each braking test, the mean and standard deviation of the mfdd shall be computed and reported. a0c0
A7  The coefficient of variation CV of a tyre braking test shall be computed as: a0c0
A7  a0c0
A7 3.4.1.2 Weighted averages of two successive tests of the SRTT shall be computed taking into account the number of candidate tyres in between: a0c0
A7  In the case of the order of testing R1 - T - R2, the weighted average of the SRTT to be used in the comparison of the performance of the candidate tyre shall be taken to be: a0c0
A7  wa(SRTT) = (R1 + R2)/2 a0c0
A7  Where: a0c0
A7  R1 is the mean fully developed deceleration for the first test of the SRTT and R2 is the mean mfdd for the second test of the SRTT. a0c0
A7  In the case of the order of testing R1 T1 T2 R2, the weighted average (wa) of the SRTT to be used in the comparison of the performance of the candidate tyre shall be taken to be: a0c0
A7  wa (SRTT) = 2/3 R1 + 1/3 R2 for comparison with the candidate tyre T1; and: a0c0
A7  wa (SRTT) = 1/3 R1 + 2/3 R2 for comparison with the candidate tyre T2. a0c0
A7 3.4.1.3. The snow grip index (SG) in per cent of a candidate tyre shall be computed as: a0c0
A7  a0c0
A7 3.4.2. Statistical validations a0c0
A7  The sets of repeats of measured or computed mfdd for each tyre should be examined for normality, drift, eventual outliers. a0c0
A7  The consistency of the means and standard-deviations of successive braking tests of SRTT should be examined. a0c0
A7  The means of two successive SRTT braking tests shall not differ by more than 5 per cent. a0c0
A7  The coefficient of variation of any braking test shall be less than 6 per cent. a0c0
A7  If those conditions are not met, tests shall be performed again after re-grooming the test course. a0c0
A7 3.4.3. In the case where the candidate tyres cannot be fitted to the same vehicle as the SRTT, for example, due to tyre size, inability to achieve required loading and so on, comparison shall be made using intermediate tyres, hereinafter referred to as "control tyres", and two different vehicles. One vehicle shall be capable of being fitted with the SRTT and the control tyre and the other vehicle shall be capable of being fitted with the control tyre and the candidate tyre. a0c0
A7 3.4.3.1 The snow grip index of the control tyre relative to the SRTT (SG1) and of the candidate tyre relative to the control tyre (SG2) shall be established using the procedure in paragraphs 3.1. to 3.4.2. above. a0c0
A7  The snow grip index of the candidate tyre relative to the SRTT shall be the product of the two resulting snow grip indices that is SG1 x SG2. a0c0
A7 3.4.3.2. The ambient conditions shall be comparable. All tests shall be completed within the same day. a0c0
A7 3.4.3.3. The same set of control tyres shall be used for comparison with the SRTT and with the candidate tyre and shall be fitted in the same wheel positions. a0c0
A7 3.4.3.4. Control tyres that have been used for testing shall subsequently be stored under the same conditions as required for the SRTT. a0c0
A7 3.4.3.5. The SRTT and control tyres shall be discarded if there is irregular wear or damage or when the performance appears to have been deteriorated. a0c0
A7 4. Acceleration method for Class C3 tyres a0c0
A7 4.1. According to the definition of C3 tyres reported into paragraph 2.4.3. above, the additional classification for the purpose of this test method only applies: a0c0
A7  (a) C3 Narrow (C3N), when the C3 tyre nominal section width is lower than 285 mm a0c0
A7  (b) C3Wide (C3W), when the C3 tyre nominal section width is greater or equal to 285 mm a0c0
A7 4.2. Methods for measuring snow grip index a0c0
A7  Snow performance is based on a test method by which the average acceleration in an acceleration test, of a candidate tyre is compared to that of a standard reference tyre. a0c0
A7  The relative performance shall be indicated by a snow grip index (SG). a0c0
A7  When tested in accordance with the acceleration test in paragraph 4.7. below, the average acceleration of a candidate snow tyre shall be at least 1.25 compared to one of the two equivalent SRTTs - ASTM F 2870 and ASTM F 2871. a0c0
A7 4.3. Measuring equipment a0c0
A7 4.3.1. A sensor suitable for measuring speed and distance covered on snow/ice surface between two speeds must be used. a0c0
A7  To measure vehicle speed, a fifth wheel or non-contact speed-measuring system (including radar, GPS ...) shall be used. a0c0
A7 4.3.2. The following tolerances shall be respected: a0c0
A7  (a) For speed measurements: ± 1 per cent (km/h) or 0.5 km/h whichever is greater. a0c0
A7  (b) For distance measurements: ± 0.1 m a0c0
A7 4.3.3. A display of the measured speed or the difference between the measured speed and the reference speed for the test is recommended inside the vehicle so that the driver can adjust the speed of the vehicle. a0c0
A7 4.3.4. For Acceleration test covered in paragraph 4.7. below, a display of the slip ratio of the driven tyres is recommended inside the vehicle and shall be used in the particular case of paragraph 4.7.2.1.1. below. a0c0
A7  The slip ratio is calculated by a0c0
A7  a0c0
A7  (a) Vehicle speed is measured as defined in 4.3.1. above (m/s) a0c0
A7  (b) Wheel speed is calculated on a tyre of the driven axle by measuring its angular velocity and its loaded diameter a0c0
A7  Wheel Speed = π x loaded diameter x angular speed a0c0
A7  Where, π = 3.1416 (m/360deg), the loaded diameter (m) and the angular speed (revolution per second = 360 deg/sec). a0c0
A7 4.3.5. A data acquisition system can be used for storing the measurements. a0c0
A7 4.4. General conditions a0c0
A7 4.4.1. Test course a0c0
A7  The test shall be done on a flat test surface of sufficient length and width, with a maximum 2 per cent gradient, covered with packed snow. a0c0
A7 4.4.1.1 The snow surface shall be composed of a hard packed snow base at least 3 cm thick and a surface layer of medium packed and prepared snow about 2 cm thick. a0c0
A7 4.4.1.2. The snow compaction index measured with a CTI penetrometer shall be between 80 and 90. Refer to the appendix of ASTM F1805 for additional details on measuring method. a0c0
A7 4.4.1.3. The air temperature, measured about one meter above the ground, shall be between -2 °C and -15 °C; the snow temperature, measured at a depth of about one centimeter, shall be between -4 °C and -15 °C. a0c0
A7  Air temperature shall not vary more than 10 deg C during the test. a0c0
A7 4.5. Tyres preparation and break-in a0c0
A7 4.5.1. Fit the test tyres on rims as per ISO 4209-1 using conventional mounting methods. Ensure proper bead seating by the use of a suitable lubricant. Excessive use of lubricant should be avoided to prevent slipping of the tyre on the wheel rim. a0c0
A7 4.5.2. The tyres should be "broken-in" prior to testing to remove spew, compound nodules or flashes resulting from moulding process. a0c0
A7 4.5.3. Tyres shall be conditioned at the outdoor ambient temperature at least two hours before their mounting for tests. a0c0
A7  They should be placed such that they all have the same ambient temperature prior to testing and be shielded from the sun to avoid excessive heating by solar radiation. a0c0
A7  The tyre surface in contact with snow shall be cleaned before performing a test. a0c0
A7  Tyre pressures shall then be adjusted to the values specified for the test. a0c0
A7 4.6. Testing sequence a0c0
A7  If only one candidate tyre is to be evaluated, the order of testing shall be: a0c0
A7  R1, T, R2 a0c0
A7  Where: a0c0
A7  R1 is the initial test of the SRTT, R2 is the repeat test of the SRTT and T is the test of the candidate tyre to be evaluated. a0c0
A7  A maximum of 3 candidate tyres may be tested before repeating the SRTT test, for example: R1, T1, T2, T3, R2. a0c0
A7  Recommendations are that the zones where acceleration is fully applied shall not overlap without reworking and when a new set of tyres is tested; a0c0
A7  The runs are performed after shifting the vehicle trajectory in order not to accelerate on the tracks of the previous tyre; when it is no longer possible not to overlap full acceleration zones, the test course should be re-groomed. a0c0
A7 4.7. Acceleration on snow test procedure for snow grip index of Classes C3N and C3W a0c0
A7 4.7.1. Principle a0c0
A7  The test method covers a procedure for measuring the snow grip performance of commercial vehicle tyres during acceleration, using a commercial vehicle having a Traction Control System (TCS, ASR, etc.). a0c0
A7  Starting with a defined initial speed, the full throttle is applied to activate the traction control system, the average acceleration is calculated between two defined speeds. a0c0
A7 4.7.2. Vehicle a0c0
A7 4.7.2.1. The test shall be conducted with a standard 2 axle commercial vehicle in good running order with: a0c0
A7  (a) Low rear axle weight and an engine powerful enough to maintain the average percentage of slip during the test as required in paragraphs 4.7.5.1. and 4.7.5.2.1. below; a0c0
A7  (b) A manual gearbox (automatic gearbox with manual shift allowed) having a gear ratio covering the speed range of at least 19 km/h between 4 km/h and 30 km/h; a0c0
A7  (c) Differential lock on driven axle is recommended to improve repeatability; a0c0
A7  (d) A standard commercial system controlling/limiting the slip of the driving axle during acceleration (Traction Control, ASR, TCS, etc.). a0c0
A7 4.7.2.1.1. In the particular case where a standard commercial vehicle equipped with a traction control system is not available, a vehicle without Traction Control/ASR/TCS is permitted provided the vehicle is fitted with a system to display the percentage slip as stated in paragraph 4.3.4. of this annex and a mandatory differential lock on the driven axle used in accordance with operating procedure 4.7.5.2.1. below. If a differential lock is available it shall be used; if the differential lock, however, is not available, the average slip ratio should be measured on the left and right driven wheel. a0c0
A7 4.7.2.2. The permitted modifications are: a0c0
A7  (a) Those allowing to increase the number of tyre sizes capable to be mounted on the vehicle; a0c0
A7  (b) Those permitting to install an automatic activation of the acceleration and the measurements. a0c0
A7  Any other modification of the acceleration system is prohibited. a0c0
A7 4.7.3. Vehicle fitting a0c0
A7  The rear driven axle may be indifferently fitted with 2 or 4 test tyres if respecting the loading by tyre. a0c0
A7  The front steer non driven axle is equipped with 2 tyres having a size suitable for the axle load. These 2 front tyres could be maintained along the test. a0c0
A7 4.7.4. Load and inflation pressure a0c0
A7 4.7.4.1. The static load on each rear driven test tyres must be between 20 per cent and 55 per cent of the tested tyre load capacity written on the sidewall. a0c0
A7  The vehicle front steer total static axle load should be between 60 per cent and 160 per cent of the driven rear total axle load. a0c0
A7  The static tyre load on the same driven axle should not differ by more than 10 per cent. a0c0
A7 4.7.4.2. The driven tyres inflation pressure shall be 70 per cent of the one written on the sidewall. a0c0
A7  The steer tyres are inflated at nominal sidewall pressure. a0c0
A7  If the pressure is not marked on the sidewall, refer to the specified pressure in applicable tyre standards manuals corresponding to maximum load capacity. a0c0
A7 4.7.5. Testing runs a0c0
A7 4.7.5.1. Mount first the set of reference tyres on the vehicle and when on the testing area. a0c0
A7  Drive the vehicle at a constant speed between 4 km/h and 11 km/h and the gear ratio capable of covering the speed range of at least 19 km/h for the complete test programme (e.g. R-T1-T2-T3-R). a0c0
A7  The recommended gear ratio selected is 3rd or 4th and shall give a minimum 10 per cent average slip ratio in the measured range of speed. a0c0
A7 4.7.5.2. In case of traction control system equipped vehicles (already switched "on" before the run) apply full throttle until the vehicle has reached the final speed. a0c0
A7  Final speed = Initial speed + 15 km/h a0c0
A7  No rearward restraining force shall be applied to the test vehicle. a0c0
A7 4.7.5.2.1. In the particular case of paragraph 4.7.2.1.1. of this annex where a standard commercial vehicle equipped with a traction control system is not available, the driver shall manually maintain the average slip ratio between 10 and 40 per cent (controlled slip procedure in place of the full slip) within the prescribed range of speeds. If a differential lock is not available, the averaged slip ratio difference between the left and right driven wheel shall not be higher than 8 per cent for each run. All the tyres and runs in the test session are performed with controlled slip procedure. a0c0
A7 4.7.5.3. Measure the distance between the initial speed and the final speed. a0c0
A7 4.7.5.4. For every candidate tyre and the standard reference tyre, the acceleration test runs shall be repeated a minimum of 6 times and the coefficients of variation (standard deviation/average*100) calculated for minimum 6 valid runs on the distance shall be lower than or equal to 6 per cent. a0c0
A7 4.7.5.5. In case of traction control system equipped vehicle, the average slip ratio shall be in the range from 10 per cent to 40 per cent (calculated as per paragraph 4.3.4. of this annex). a0c0
A7 4.7.5.6. Apply testing sequence as defined in paragraph 4.6. above. a0c0
A7 4.8. Processing of measurement results a0c0
A7 4.8.1. Calculation of the average acceleration AA a0c0
A7  Each time the measurement is repeated, the average acceleration AA (m s-2) is calculated by a0c0
A7  a0c0
A7  Where D (m) is the distance covered between the initial speed Si (m.s-1) and the final speed Sf (m.s-1) a0c0
A7 4.8.2. Validation of results a0c0
A7  For the candidate tyres: a0c0
A7  The coefficient of variation of the average acceleration is calculated for all the candidate tyres. If one coefficient of variation is greater than 6 per cent, discard the data for this candidate tyre and repeat the test. a0c0
A7  a0c0
A7  For the reference tyre: a0c0
A7  If the coefficient of variation of the average acceleration "AA" for each group of min 6 runs of the reference tyre is higher than 6 per cent, discard all data and repeat the test for all tyres (the candidate tyres and the reference tyre). a0c0
A7  In addition and in order to take in account possible test evolution, the coefficient of validation is calculated on the basis of the average values of any two consecutive groups of min 6 runs of the reference tyre. If the coefficient of validation is greater than 6 per cent, discard the data for all the candidate tyres and repeat the test. a0c0
A7  a0c0
A7 4.8.3. Calculation of the "average AA" a0c0
A7  If R1 is the average of the "AA" values in the first test of the reference tyre, R2 is the average of the "AA" values in the second test of the reference tyre, the following operations are performed, according to Table 1: a0c0
A7  a0c0
A7 4.8.4 "AFC" Calculation (Acceleration Force Coefficient) a0c0
A7  Also called AFC Acceleration Force Coefficient a0c0
A7  Calculation on of AFC(Ta) and AFC(Ra) as defined in Table 2 : a0c0
A7  a0c0
A7 4.8.5. Calculation of the relative snow grip index of the tyre a0c0
A7  The snow grip index represents the relative performance of the candidate tyre compared to the reference tyre. a0c0
A7  a0c0
A7 4.8.6. Calculation of the slip ratio a0c0
A7  The slip ratio can be calculated as the average of slip ratio as mentioned in paragraph 4.3.4. of this annex or by comparing the average distance referred to in paragraph 4.7.5.3. of this annex of the minimum 6 runs to the distance of a run done without slip (very low acceleration) a0c0
A7  a0c0
A7  No slip distance means the wheel distance calculated on a run done with a constant speed or a continuous low acceleration. a0c0
A7 4.9. Snow grip performance comparison between a candidate tyre and a reference tyre using a control tyre a0c0
A7 4.9.1. Scope a0c0
A7  When the candidate tyre size is significantly different from the reference tyre a direct comparison on the same vehicle may be not possible. This is an approach using an intermediate tyre, hereinafter called the control tyre. a0c0
A7 4.9.2. Principle of the approach a0c0
A7  The principle lies upon the use of a control tyre and 2 different vehicles for the assessment of a candidate tyre in comparison with a reference tyre. a0c0
A7  One vehicle can fit the reference tyre and the control tyre, the other the control tyre and the candidate tyre. All conditions are in conformity with paragraph 4.7. above . a0c0
A7  The first assessment is a comparison between the control tyre and the reference tyre. The result (snow Grip Index 1) is the relative efficiency of the control tyre compared to the reference tyre. a0c0
A7  The second assessment is a comparison between the candidate tyre and the control tyre. The result (snow grip index 2) is the relative efficiency of the candidate tyre compared to the control tyre. a0c0
A7  The second assessment is done on the same track as the first one. The air temperature must be in the range of +/- 5 deg C of the temperature of the first assessment. The control tyre set is the same set as the set used for the first assessment. a0c0
A7  The snow grip performance index of the candidate tyre compared to the reference tyre is deduced by multiplying the relative efficiencies calculated above: a0c0
A7  Snow Grip Index = SG1 x SG2 a0c0
A7 4.9.3. Selection of a set of tyres as a control tyre set a0c0
A7  A control tyre set is a group of identical tyres made in the same factory during one week period. a0c0
A7 4.10. Storage and preservation a0c0
A7  Before the first assessment (control tyre / reference tyre), normal storage conditions can be used. It is necessary that all the tyres of a control tyre set have been stored in the same conditions. a0c0
A7  As soon as the control tyre set has been assessed in comparison with the reference tyre, specific storage conditions shall be applied for control tyres replacement. a0c0
A7  When irregular wear or damage results from tests, or when wear influences the test results, the use of the tyre shall be discontinued. a0c0
A7  Annex 7 – Appendix 1 a0c0
A7  Pictogram definition of "Alpine Symbol" a0c0
A7  a0c0
A7  Minimum 15 mm base and 15 mm height. a0c0
A7  Above drawing not to scale. a0c0
A7  Annex 7 – Appendix 2 a0c0
A7  Test reports and test data for C1 and C2 tyres a0c0
A7  Part 1 - Report a0c0
A7 1. Type Approval Authority or Technical Service: a0c0
A7 2. Name and address of applicant: a0c0
A7 3. Test report No.: a0c0
A7 4. Manufacturer and brand name or trade description: a0c0
A7 5. Tyre class: a0c0
A7 6. Category of use: a0c0
A7 7. Snow index relative to SRTT according to paragraph 6.4.1.1. a0c0
A7 7.1. Test procedure and SRTT used a0c0
A7 8. Comments (if any): a0c0
A7 9. Date: a0c0
A7 10. Signature: a0c0
A7  Part 2 - Test data a0c0
A7 1. Date of test: a0c0
A7 2. Location of test track: a0c0
A7 2.1. Test track characteristics: a0c0
A7  a0c0
A7 3. Test vehicle (make, model and type, year): a0c0
A7 4. Test tyre details a0c0
A7 4.1. Tyre size designation and service description: a0c0
A7 4.2. Tyre brand and trade description: a0c0
A7 4.3. Test tyre data: a0c0
A7  a0c0
A7 5. Test results: mean fully developed decelerations (m/s^2) / traction coefficient[1] a2c0
A7  a2c0
A7 [1] Strike out what does not apply. a0c0
A7  Annex 7 – Appendix 3 a0c0
A7  Test reports and test data for C3 tyres a0c0
A7  Part 1 - Report a0c0
A7 1. Type Approval Authority or Technical Service: a0c0
A7 2. Name and address of applicant: a0c0
A7 3. Test report No.: a0c0
A7 4. Manufacturer and brand name or trade description: a0c0
A7 5. Tyre class: a0c0
A7 6. Category of use: a0c0
A7 7. Snow grip index relative to SRTT according to paragraph 6.4.1.1. a0c0
A7 7.1. Test procedure and SRTT used a0c0
A7 8. Comments (if any): a0c0
A7 9. Date: a0c0
A7 10. Signature: a0c0
A7  Part 2 - Test data a0c0
A7 1. Date of test: a0c0
A7 2. Location of test track: a0c0
A7 2.1. Test track characteristics: a0c0
A7  a0c0
A7 3. Test vehicle (make, model and type, year): a0c0
A7 4. Test tyre details a0c0
A7 4.1. Tyre size designation and service description: a0c0
A7 4.2. Tyre brand and trade description: a0c0
A7 4.3. Test tyre data: a0c0
A7  a0c0
A7 5. Test results: average accelerations (m/s^2) a0c0
A7  a0c0