UN R117/02 (Rev.4)

2.  Arrangements of approval marks

Appendix 1 - Example of separate Regulation No. 117 approval marks

Appendix 2 - Approval according to Regulation No. 117 coincident with approval of Regulation No. 30 or 54

Appendix 3 - Combinations of markings approvals issued in accordance with Regulations Nos. 117, 30 or 54

5. Test procedures for measuring wet adhesion of new tyres

(omitted)

Appendix 1 - Pictogram definition of "Alpine Symbol"

8. Procedures for ice performance testing relative to ice grip tyre of class C1

Appendix 1 - Pictogram definition of "Ice Grip Symbol";

Appendix 2 - Test reports and test data for class C1 tyres

Tyres with a speed DEL category less than 80 km/h (speed symbol F);

(b) The tyre class (see paragraph 2.6. below);

(f) For class C1 tyres, whether ice grip tyre or not;

(g) For Classes C2 and C3 tyres, whether traction tyre or not:

(h) The tread pattern (see paragraph 3.2.1. of this Regulation).

"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.

"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 measuring snow performance, or Annex 8 for measuring ice performance."

"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 paragraphs 6.4. and 6.4.1. of this Regulation."

"Ice grip tyre" means a class C1 snow tyre for use in severe snow conditions that is additionally designed to be used on road surfaces covered with ice and that fulfils the requirements of paragraph 6.4.2. of this Regulation."

"Standard Reference Test Tyre" or "SRTT" means a tyre that is produced, controlled and stored in accordance with the standards of ASTM International:

(a) E1136 - 17 [DEL] for the size P195/75R14 and referred to as "SRTT14", 

(b) F2493 – 20 for the size P225/60R16 and referred to as "SRTT16",

(c) F2872 – 16 for the size 225/75R16C and referred to as "SRTT16C",

(d) F2871 – 16 for the size 245/70R19.5 and referred to as "SRTT19.5",

(e) F2870 – 16 for the size 315/70R22.5 and referred to as "SRTT22.5".

Wet grip or snow DEL performance or ice performance measurements - Specific definitions

"Adhesion on wet surfaces" or "wet adhesion" 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 Standard Reference Test Tyre (SRTT).

"Candidate tyre" or "candidate tyre set" means a tyre or a tyre set, representative of the type that is submitted for approval in accordance with this Regulation and whose performances are evaluated relative to that of a reference tyre or reference tyre set.

"Reference tyre" or "reference tyre set" means a tyre or a tyre set of Standard Reference Test Tyres as defined in the respective annex.

"Control tyre" or "control tyre set" means a normal production tyre or a normal production tyre set that is used to establish the wet DEL adhesion level or snow DEL performance level or ice performance level of tyre sizes unable to be fitted to the same vehicle as the DEL reference tyre or reference tyre set – see paragraph 2.2.2.8. of Annex 5, part (B), paragraph 3.4.3. of Annex 7 and paragraph 2.4.5.1.1. of Annex 8 to this Regulation.

"Test tyre" means a candidate tyre, reference tyre or control tyre.

"Wet grip index" (G) means the dimensionless unit for expressing the wet adhesion level of a candidate tyre relative to that of the applicable DEL SRTT."

"Snow grip index" (SG) means the dimensionless unit for expressing the snow DEL performance level of a candidate tyre relative to the performance of the applicable SRTT."

"Ice grip index" (GI) means the dimensionless unit for expressing the ice performance level of a candidate tyre relative to the performance of the applicable SRTT.

"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.

"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.

"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.

"Test run" means a single pass of a loaded tyre over a given test surface.

"Braking test" means a series of a specified number of test runs of the same test tyre repeated within a short time frame.

"Traction test" means a series of a specified number of spin-traction test runs of the same tyre repeated within a short time frame.

"Acceleration test" means a series of specified number of traction controlled acceleration test runs of the same tyre repeated within a short timeframe.

"Test cycle" means a series of braking tests, traction tests or acceleration tests that consist of an initial test of the reference tyre or the control tyre, of tests of candidate tyres and/or control tyres and a final test of the same reference tyre or control tyre."

"Rolling resistance (Fr)"

Rolling resistance coefficient (Cr)

Means the ratio of the rolling resistance to the load on the tyre.[4]

means a tyre which has not been previously used in a rolling deflected test [DEL] which elevates the tyre's temperature to higher than that generated in rolling resistance tests, and which has not previously been exposed to a temperature above 40 ºC.[5], [6]

Means a tyre used by an individual laboratory to control machine behaviour as a function of time.[7]

Means the 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.

Means a 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.

Measurement reproducibility (σm)

Means the capability of a machine to measure rolling resistance.[9]

The performance characteristics to be assessed for the type of tyre; "rolling sound emissions level" and/or "adhesion performance level on wet surfaces" and/or "rolling resistance level"; "snow performance level" in case of "snow tyre for use in severe snow conditions" and additionally "ice performance level" in case of ice grip tyre;"

Manufacturer's name and address;

If applicable, name and address of [DEL] manufacturer's representative;

Tyre class (Class C1, C2 or C3) (see paragraph 2.6. of this Regulation);

Category of use (normal, snow, or special);

Whether snow tyre for use in severe snow conditions or not;

For classes C2 and C3 tyres, whether traction tyre or not;

For class C1 tyres, whether ice grip tyre or not;

Tyre structure;

Brand name(s)/trademark(s), trade description(s)/commercial name(s);

A list of tyre size designations covered by this application and specifying for each brand name/trademark and/or each trade description/commercial name the applicable tyre size designations and service descriptions, adding in case of Class C1 tyres whether "reinforced" (or "extra load") or not.

[DEL]

[DEL]

[DEL]

[DEL]

[DEL]

[DEL]

[DEL]

[DEL]

[DEL]

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, snow performance and ice performance) 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 or Computer Tomography (CT) scans, 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;

Drawings or photographs of the tyre sidewall, showing the DEL approval marks 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;

With regard to the application, testing may be confined to a [DEL] representative tyre size of the type of tyre, at the discretion of the Type Approval Authority [DEL].

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;

The "Alpine Symbol" ("3-peak-mountain with snowflake" conforming to the pictogram described in Annex 7, Appendix 1) DEL if the snow tyre is classified as "snow tyre for use in severe snow conditions";

The "Ice Grip Symbol" (conforming to the pictogram described in Annex 8, Appendix 1) if the snow tyre for use in severe snow conditions is additionally classified as ice grip tyre;

In case the approval of a tyre pursuant to this Regulation has been granted by the same Type Approval Authority than that granting the approval pursuant to UN Regulations Nos. 30 or 54, the approval mark pursuant to UN Regulations Nos. 30 or 54 can be combined with an indication of the applicable series of amendments to which the tyre was approved pursuant to UN Regulation No. 117 on the form of 2 digits (example "02" indicating that the UN Regulation No.117 approval was granted following the 02 series of amendments) and the suffixes according to paragraph 5.2.2. using the addition sign "+", as described in Annex 2, Appendix 3 of this Regulation, for example "0236378 + 02S1WR2".

[DEL] The markings referred to in paragraph 4.2. and the approval mark prescribed in paragraph 5.4. of this Regulation shall be clearly legible, indelible and raised above or sunk below the tyre surface.

The markings shall be situated in the lower area of the tyre on at least one of its sidewalls. However, in the case of tyres identified by the "tyre to rim fitment configuration" symbol "A" or "U", the markings may be located anywhere on the outside sidewall of the tyre.

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, (all) the specific type approval number(s) and the Regulation itself shall be added to item 9. of Annex 1 "Communication" DEL.

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).

If the approval is extended subsequent to Regulation Nos. 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.

If the approval is extended subsequent to the original approval under UN 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.

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.<mod>2</mod>.2. above.

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 DEL defined in UN Regulation No. 30:

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:

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:

The wet DEL adhesion 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).

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:

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:

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:

of the candidate tyre is compared to that of a Standard Reference Test Tyre (SRTT).

The relative performance shall be indicated by a snow grip index.

DEL Snow performance requirements for classes C1, C2 and C3 tyres

DEL

The minimum snow grip index value, as calculated in the procedure described in Annex 7 and compared with the respective Standard Reference Test Tyre (SRTT) shall be as follows:

Ice performance requirements for class C1 tyres classified as ice grip tyre

In order to be classified as ice grip tyre, a snow tyre for use in severe snow conditions shall meet the minimum ice grip index value, as calculated in the procedure described in Annex 8 and compared with the respective Standard Reference Test Tyre (SRTT) shall be as follows:

In order to be classified as a "traction tyre", a tyre is required to meet at least one of the conditionDEL of paragraph 6.5.1. below.

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 DEL appropriate test methods and limit values.

For class C1 tyres: a tread depth ≥ 11 mm and void to fill ratio ≥ 35 per cent

For class C2 tyres: a tread depth ≥ 11 mm and void to fill ratio ≥ 35 per cent

For class C3 tyres: a tread depth ≥ 16 mm and void to fill ratio ≥ 35 per cent

(a) For classes C1 and C2 tyres:

(b) For class C3 tyres:

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.

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.

The conformity of production procedures shall comply with those set out in the 1958 Agreement, Schedule 1 (E/ECE/324-E/ECE/TRANS/505/Rev.3) with the following requirements:

DEL The authority which has granted type approval may at any time verify the conformity control methods applied by the manufacturer. In general, the conformity control methods should take into consideration the production volumes of the type of tyre at each manufacturing facility. The normal frequency of these verifications shall be at least once every two years.

Verification tests shall be carried out on random samples of tyres bearing the approval mark required by this Regulation taken from the series production. 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 measuring wet adhesion 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. The Type Approval Authority shall satisfy itself that all tyres falling within an approved type comply with the approval requirement.

In the case of verification tests with regard to approvals in accordance with paragraph 6.2. of this Regulation, these shall be carried out using the same testing method (see Annex 5 to this Regulation) as that adopted for original approval.

In the case of verification tests with regard to approvals in accordance with paragraph 6.4. of this Regulation, these shall be carried out using the same testing method (see Annex 7 to this Regulation) as that adopted for original approval.

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.

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.

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 paragraphs 8.4. or 8.5. above.

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 adhesion 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.

As from 1 November 2012, Contracting Parties applying this Regulation shall refuse to grant approval if the type of tyre 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 adhesion 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.

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 adhesion requirements set out in paragraph 6.2.1. of this Regulation.

As from 1 November 2016, Contracting Parties applying this Regulation shall refuse to grant approvals if the type of tyre 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 adhesion requirements set out in paragraphs 6.2.2. and 6.2.3. of this Regulation.

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 adhesion requirements set out in paragraphs 6.2.2. and 6.2.3. of this Regulation:

Until 3 months after the date of entry into force of Supplement 11 to the 02 series of amendments to this Regulation, Contracting Parties applying this Regulation can continue to grant type approvals according to the 02 series of amendments to this Regulation, without taking into account the provisions of Supplement 11.

Until 3 months after the date of entry into force of Supplement 13 to the 02 series of amendments to this Regulation, Contracting Parties applying this Regulation can continue to grant type approvals according to the 02 series of amendments to this Regulation, without taking into account the provisions of Supplement 13.

Until 1 September 2024, Contracting Parties applying this Regulation may continue to grant type approvals according to the 02 series of amendments to this Regulation, based on snow performance test described in Annex 7 to this Regulation using SRTT14 as reference tyre. ^(a)

^(a) SRTT14 will be available from the supplier until end of October 2021.

Until 1 September 2024, Contracting Parties applying this Regulation may continue to grant type approvals according to the 02 series of amendments to this Regulation, based on the test procedures for measuring wet adhesion described in Annex 5 of this Regulation, without taking into account the provisions of Supplement 13.

Until 3 months after the date of entry into force of Supplement 14 to the 02 series of amendments to this Regulation, Contracting Parties applying this Regulation can continue to grant type approvals according to the 02 series of amendments to this Regulation, without taking into account the provisions of Supplement 14.

Manufacturer's name and address [DEL]:

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

Category of use" of the type of tyre:

Snow tyre for use in severe snow conditions (Yes/No)[2]

Ice grip tyre (Yes/No)[2]

Traction tyre (Yes/No)[2]

Tyre structure:

Type of tyre designation:

Brand name(s)/trademark(s) of the type of tyre:

Trade description(s)/ commercial name(s) of the type of tyre:

Technical service and, where applicable, test laboratory approved for purposes of approval or of verification of conformity tests:

Performance(s) approved: sound level at (stage 1/stage 2),[2] wet adhesion level, rolling resistance level (stage 1/stage 2)[2]

Sound level of the representative tyre size, see paragraph 2.7. 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]

Wet adhesion level of the representative tyre size, see paragraph 2.7. of this Regulation, as per DEL the test report examples shown in the appendix to Annex 5: ……………………… (G) using the vehicle or trailer method [2]

Rolling resistance level of the representative tyre size, see paragraph 2.7. of this Regulation, as per item 7. of the test report in Appendix 1 to Annex 6

Snow performance level of the representative tyre size, see paragraph 2.7. of DEL Regulation No. 117, as per item 7. of the test report in the appendix [5] to Annex 7:………………. (snow grip index) using the brake on snow method [2], spin traction method [2] or acceleration method [2].

Ice performance level of the representative tyre size, see paragraph 2.7. of Regulation No. 117, as per item 7. of the test report in the appendix 2 to Annex 8:…………………….…(ice grip index) using the brake on ice method. [2]

Number of report issued by the Technical Service:

Date of report issued by that Service:

Reason(s) of extension (if applicable):

Any remarks:

Place:

Date:

Signature:

Annexed to this communication are:

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. [6]

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 and service descriptions, adding in case of class C1 tyres whether "reinforced" (or "extra load") or not.

Appendix 2 for classes C1 and C2 tyres.

Appendix 3 for class C3 tyres.

In the case of "snow tyre for use in severe snow conditions" a test report according to Appendix 2 or Appendix 3, as applicable, to Annex 7 shall be submitted.

Annex 2 – Arrangements of approval marks

Example of separate UN Regulation No. 117 approval marks

The above approval mark, affixed to a tyre shows that a tyre concerned has been approved in the Netherlands (E 4) pursuant to Regulation No. 117 (marked by "S2") DEL, under approval number 0212345. This indicates that the approval is for rolling sound at stage 2 (S2). The first two digits of the approval number (02) indicate that the approval was granted in accordance with this Regulation which included 02 series of amendments DEL.

The above approval mark shows that the tyre concerned has been approved in the Netherlands (E 4) pursuant to Regulation No. 117 (marked by "S1WR1") under approval number 0212345. This indicates that the approval is for rolling sound at stage 1 (S1), wet adhesion (W) and rolling resistance at stage 1 (R1). The first two digits of the approval number ("02") indicate that the approval was granted in accordance with this Regulation which included the 02 series of amendments.

Approval according to UN Regulation No. 117 coincident with approval of UN Regulation No. 30 or 54 [1]

The above approval mark shows that the tyre concerned has been approved in the Netherlands (E 4) pursuant to UN Regulation No. 117 (marked by "S2" DEL), under approval number 0212345 and UN Regulation No. 30, under approval number 0236378. This indicates that the approval is for rolling sound at stage 2 (S2). The first two digits of the approval number ("02") in conjunction with "S2" indicate that the approval was granted in accordance with UN Regulation No. 117 which included the 02 series of amendments. The first two digits of the UN Regulation No. 30 approval number ("02") indicate that this Regulation included the 02 series of amendments.

The above approval mark shows that the tyre concerned has been approved in the Netherlands (E 4) pursuant to UN Regulation No. 117 (marked by S2WR2 DEL ), 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.

The above approval mark shows that the tyre concerned has been approved in the Netherlands (E 4) pursuant to UN Regulation No. 117 (marked by "S2WR2" DEL), under approval number 0212345 and UN Regulation No. 30, under approval number 0236378. This indicates that the approval is for rolling sound at stage 2 (S2), wet adhesion (W) and rolling resistance at stage 2 (R2). The first two digits of the approval number ("02") in conjunction with "S2WR2" indicate that the first approval was granted in accordance with UN Regulation No. 117 which included the 02 series of amendments. The first two digits of the UN Regulation No. 30 approval number ("02") indicate that this Regulation included the 02 series of amendments.

Combinations of markings of approvals issued in accordance with UN Regulations Nos. 117, 30 or 54

The above approval mark shows that the tyre concerned has been [DEL] approved in the Netherlands (E 4) pursuant to UN Regulation No. 30 according to its 02 series of amendments (indicated by the first two digits of the approval number, "02") under approval number 0236378. It is also marked by "+ 02S1" which indicates that the tyre was also approved pursuant to UN Regulation No. 117 (02 series of amendments) for rolling sound at stage 1.

The above approval mark shows that the tyre concerned has been approved in the Netherlands (E 4) pursuant to Regulation No. 30 according to its 02 series of amendments (indicated by the first two digits of the approval number, "02") under approval number 0236378. It is also marked by "+ 02S1WR2" which indicates that the tyre was also approved pursuant to UN Regulation No. 117 (02 series of amendments) for S1 (rolling sound at stage 1), W (wet adhesion) and R2 (rolling resistance at stage 2)

Extensions to combine approvals issued in accordance with Regulation No. 117 DEL

DEL.

The above approval mark shows that the tyre concerned has been initially approved in the Netherlands (E 4) pursuant to UN Regulation No. 117 according to its 02 series of amendments (indicated by the first two digits of the approval number, "02") under approval number 0212345 (marked by "W"). This indicates that the approval is for W (wet adhesion). The "S2R2" preceded by "+" indicates that its approval has been extended under UN Regulation No. 117 to rolling sound at stage 2 and rolling resistance at stage 2 based on separate certificate(s).

The above approval mark shows that the tyre concerned has been initially approved in the Netherlands (E 4) pursuant to UN Regulation No. 117 according to its 02 series of amendments (indicated by the first two digits of the approval number, "02") under approval number 0212345 (marked by "S1W"). This indicates that the approval is for S1 (rolling sound at stage 1) and W (wet adhesion). The "R1" preceded by "+" indicates that its approval has been extended under Regulation No. 117 to rolling resistance at stage 1 based on separate certificate(s).

The above approval mark shows that the tyre concerned has been initially approved in the Netherlands (E 4) pursuant to UN Regulation No. 117 according to its 01 series of amendments (indicated by the first two digits of the approval number, "01") under approval number 0167890 (marked by "SW"). This indicates that the approval is for S (rolling sound at stage 1) and W (wet adhesion). The "02R1" preceded by "+" indicates that its approval has been extended under UN Regulation No. 117 according to its 02 series of amendments to rolling resistance at stage 1 based on separate certificate(s).

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 [DEL] IEC 61672-1:2013.

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:[DEL]2017. 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.

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.

Four identical tyres shall be fitted on the test vehicle. In the case of class C3 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.

In the case of class C2 tyres with a load capacity index lower or equal to 121, with a section width wider than 200 mm, an aspect ratio lower than 55, a rim diameter code lower than 15 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 a 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.

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.

Tyres are to be tested on rims permitted by the tyre manufacturer."

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.

For class C2 and class C3 the reference pressure Pr is the inflation pressure corresponding to the  DEL indication of the inflation pressure marked on the sidewall as required by paragraph 4.1. of this Regulation.

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.

(a) From 70 to 90 km/h for class C1 and class C2 tyres;

(b) From 60 to 80 km/h for class C3 tyres.

(a) 80 km/h for class C1 and class C2 tyres;

(b) 70 km/h for class C3 tyres.

Temperature correction

For Class C1 and Class C2 tyres, [DEL] the rolling sound levels Li(&thetasymi) obtained at the test surface temperature &thetasymi (where i denotes the number of the single measurement) shall be normalized to a test surface reference temperature &thetasymref by applying a temperature correction, according to the following formula:

Notwithstanding the above procedure, the temperature correction may be made only on the final reported tyre rolling sound level L_R, utilizing the arithmetic mean value of the measured temperatures, 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.[DEL] In this case the regression analysis below shall be based on the uncorrected rolling sound levels Li(&thetasymi). There will be no temperature correction for Class C3 tyres.

Regression analysis of rolling sound measurements

The tyre-road rolling sound level L_R(&thetasymref) in dB(A) is determined by a regression analysis according to:

In order to take account of any measuring instrument inaccuracies, the temperature corrected tyre rolling sound level L_R(&thetasymref) in dB(A) shall be reduced by 1 dB(A) and then rounded down to the nearest lower whole value to obtain the final result.

[DEL]

Name and address of manufacturer [DEL]:

[DEL] Brand Name and [DEL] Trade description:

Snow tyre use in severe snow conditions (Yes/No)¹

Traction tyre (Yes/No)¹

Sound level according to paragraphs 4.4. [DEL] of Annex 3: ...........dB(A)

Reference (test) inflation pressure²: kPa

for classes C2 and C3 tyres, corresponding to the indication of the inflation pressure marked on the sidewall as required by paragraph 4.1. of this Regulation

Sound level [DEL] according to paragraph 4.3. of Annex 3: dB(A)

Annex 4

Test procedures for measuring wet adhesion of new tyres

(A) - Class C1 tyres

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ASTM E 965-96 (Reapproved 2006), Standard Test Method for Measuring Pavement Macrotexture Depth Using a Volumetric Technique.

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In addition to the definitions in paragraph 2. of the main body of this Regulation, for the purposes of testing wet adhesion of  class C1 tyres:

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"Reference tyre" or "Reference tyre set" means a tyre or a tyre set of Standard Reference Test Tyres SRTT16.

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"Braking force" means the longitudinal force, expressed in newtons, resulting from braking torque application.

"Average Braking Force Coefficient" (BFC) means, for the vehicle method, the ratio of the average deceleration in a braking test to the acceleration due to gravity (rounded to 9.81 m∙s−2).

"Dynamic braking force coefficient" (μ(t)) means, for the trailer (or tyre test vehicle) method, the ratio of the braking force to the vertical load acquired in real time.

"Peak braking force coefficient" (μpeak) means, for the trailer (or tyre test vehicle) method, the maximum value of the dynamic braking force coefficient that occurs prior to lockup of the wheel as the braking torque is progressively increased.

"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.

"Vertical load" means the normal force, expressed in newtons, exerted on the road resulting from the mass supported by the tyre.

"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.

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"Tyre set" means, for the trailer (or tyre test vehicle) method, one (1) tyre and, for the vehicle method, four (4) tyres.

"Instrumented passenger car" means a commercialized passenger car equipped with an Antilock Braking System (ABS) and the measuring equipment listed in paragraph 4.1.2.2. of this Annex..

The surface shall have a dense asphalt surface with a uniform gradient of not more than 2 per cent in both longitudinal and lateral directions and shall not deviate more than 6 mm when tested with a 3 m straight edge.

The average macro texture depth as measured in accordance with ASTM E965-96 (Reapproved 2006) by a sand patch shall be 0.7 ± 0.3) mm. [DEL] In case the vehicle method is used, the average macro texture depth shall be determined in both lanes where the tyres are going to brake.

The wetted frictional properties of the surface shall be measured using the SRTT16 either with the method described in paragraph 3.2.1. of this Annex in case the vehicle method (according to paragraph 4.1. below) is used, or with the method described in paragraph 3.2.2. in this Annex in case the trailer (or tyre test vehicle) method is used.

Using the procedure described in paragraph 4.1. of this Annex, perform two braking tests of the reference tyre, each consisting of at least six (6) valid test runs in the same direction on aligned segments of the track. The braking tests shall cover the entire potential braking area, including where the texture depth was measured.
Evaluate the braking tests as described in paragraphs 4.1.6.1. and 4.1.6.2. of this Annex. If the coefficient of variation of one braking test CV_BFC exceeds 4 per cent, dismiss the results and repeat the braking tests.

For each braking test, the arithmetic mean    of the average Braking Force Coefficients shall be corrected for effects of temperature as follows:

where
ϑ is the wetted surface temperature in degrees Celsius,
𝑎= 0.002 ℃ −1 and ϑ₀=20 ℃.

For each braking test, the temperature-corrected average Braking Force Coefficient (BFC_ave,corr) shall be not less than 0.57 and not greater than 0.79.
The arithmetic means of the temperature-corrected average Braking Force Coefficients of the two braking tests shall not differ by more than 10 per cent of the average of the two values:

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Using the procedure described in paragraph 4.2. of this Annex, perform in the same area where the average macro texture depth was measured one braking test of the reference tyre, consisting of at least six (6) valid test runs in the same direction.

Evaluate the braking test as described in paragraphs 4.2.8.1. and 4.2.8.2. of this Annex. If the coefficient of variation CV_μ exceeds 4 per cent, dismiss the results and repeat the braking test.

The arithmetic mean  of the measured peak braking force coefficients shall be corrected for effects of temperature as follows:

where

ϑ is the wetted road surface temperature in degrees Celsius,

a= 0.002 ℃ −1 and ϑ₀=20°C.

The temperature-corrected average peak braking force coefficient (μ_peak,corr) shall be not less than 0.65 and not greater than 0.90.

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The wetted surface temperature and the ambient temperature shall be between:

Moreover, the wetted surface temperature shall not vary during the test by more than 10 C.

The ambient temperature shall remain close to the wetted surface temperature; the difference between the ambient and the wetted surface temperatures shall be less than 10 °C.

Replacement of reference tyres [DEL]

When irregular wear or damage results from tests, or when wear or aging influences the test results, the use of the reference tyre shall be discontinued.

Testing methods for measuring wet adhesion

The testing method covers a procedure for measuring the deceleration performance of class C1 tyres during braking, using an instrumented passenger car.
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.

Any commercialized passenger car, preferably not older than 5 years, type approved pursuant to UN Regulation No. 13-H with regards to its braking system, which is fitted with an anti-lock system (ABS), shall be considered as suitable for the purpose of the test provided that the mechanical conditions of the passenger car meet the car manufacturer’s recommendations and no warning from ABS (e.g. warning lights) is displayed.

Permitted modifications on the passenger car are as follows:

(c) [DEL] Those permitting the vehicle to be guided or accelerated externally.

Any other modification of the vehicle and specifically of the braking system is prohibited.

The exposed portions of the system shall tolerate 100 per cent relative humidity (rain or spray) and all other conditions, such as dust, shock and vibrations, which may be encountered in regular operation.
The vehicle shall be fitted with a sensor suitable for measuring speed on a wet surface and distance covered between two speeds.

To measure vehicle speed, a fifth wheel or non-contact precision (including e. g. radar, GPS, etc.) speed-measuring system shall be used.
The following tolerances shall be respected:

(a) For speed measurement: ± 1 % or ± 0.5 km/h, whichever is greater;

(b) For distance: ± 1 ∙ 10–1 m."

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.

Tyre preparation and stabilization, rims and fitment on the vehicle

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.

Rim width code shall not differ by more than 0.5 from the measuring rim width code. 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.

The tyres should be stabilized in performance prior to testing, which means that no evolution of the BFC value in test runs should be detectable; in any case there will be an ex-post verification according to paragraph 4.1.6.2. of this Annex. In all cases, tyre designed tread depth and designed tread block or rib integrity shall not change significantly with break-in, which means the pace and "severity" of the break-in needs to be carefully controlled to avoid such changes.

Place the fitted test tyres in a location 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.

Maximum spacer (adapter) width allowed to mount tyres on the vehicle is 60 mm.

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.

It is prohibited to exceed the maximum axle load of the vehicle.

On the front axle [DEL], the inflation pressures p shall be calculated as follows:

where
pref is the reference inflation pressure (250 kPa for standard-load and 290 kPa for extra-load versions, regardless of the reference pressure in the applicable standard);
Q is the average tyre vertical load on the front axle;
Q_ref is the reference vertical load associated with the load-capacity index.

On the rear axle, the inflation pressure shall be 220 kPa (for both standard-load and extra-load versions). The tyre pressure should be checked just prior to testing at ambient temperature and adjusted if required.

The passenger car is driven in a straight line up to (85 ± 2) km/h.

Once the passenger car has reached (85 ± 2) km/h, the brakes shall always be 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. Braking tests shall occur on the same lanes and in the same direction that was used to examine the surface, including where the macro texture depth was measured, in accordance with paragraphs 3.1.4. and 3.1.5. above (with a transverse tolerance of 0.5 m)."

The manual activation of the brakes depends on the type of transmission as follows. In both cases, [DEL] the pedal effort shall be high enough to activate the ABS.

For manual transmission, as soon as the driver is in the measuring zone and having reached (85 ± 2) km/h, the driver should release the clutch and depress the brake pedal sharply, holding it down as long as necessary to perform the measurement.

For automatic transmission, as soon as the driver is in the measuring zone and having reached (85 ± 2) km/h, the driver should select neutral gear and then depress the brake pedal sharply, holding it down as long as necessary to perform the measurement.

For each braking test and for tyres not tested before, the first two runs shall be discarded.

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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 test run is invalidated and a new test run is made.

Braking test and test cycle

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Within the same test cycle, each test run of each braking test shall be made in the same direction and in accordance with paragraph 4.1.5.1. of this Annex. Several test cycles may be performed consecutively, where the final braking test of the reference tyre set of a test cycle may serve as the initial braking test of the reference test tyre set for the next test cycle.
Up to three different candidate tyre sets may be measured within the same test cycle according to the following procedure:

Initial braking test of the reference tyre (R_i): First, the [DEL] reference tyre set is mounted on the instrumented passenger car and at least four (4) valid test runs shall be made.

Braking test of a candidate tyre set (T_n): [DEL] The reference tyre set is replaced by a [DEL] candidate tyre set (T_n) and at least six (6) valid test runs of the candidate tyres shall be performed.

After [DEL] the braking test of the first candidate tyre set [DEL], up to two more [DEL] candidate tyre sets may be measured.

Final braking test of the reference tyres (Rf): The test cycle is closed by [DEL] at least four (4) valid [DEL] test runs of the same [DEL] reference tyre set as at the beginning of the test cycle.

(a) The run order for a test cycle of three sets of candidate tyres (T₁ to T₃) [DEL] would be the following:

R_i – T₁ – T₂ – T₃ – R_f

(b) The run order for a braking test (consisting of two test cycles) of five [DEL] candidate tyre sets (T₁ to T₅) would be the following:
R_i – T₁ – T₂ – T₃ – R_f/R_i – T₄ – T₅ – R_f

Calculation of the average Braking Force Coefficient

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For each valid test run j, the average Braking Force Coefficient BFCave,j is calculated from the distance dj covered between 80 km/h and 20 km/h as follows:

νf is the final speed in m/s;  ν_f = 20 km/h = 5.556 m/s

ν_i is the initial speed in m/s;  ν_i = 80 km/h = 22.222 m/s

d_j is the distance covered in test run j between ν_i and ν_f in meter.

g is the acceleration due to gravity = 9.81 m∙s⁻².

The [DEL] coefficient of variation CV_BFC is calculated as follows:

where

denotes the corrected sample standard deviation and  the arithmetic mean of the average Braking Force Coefficients BFC_ave,j of N test runs.

For the reference tyres [DEL]:

(a) The coefficient of variation CV_BFC of the initial and the final braking test of the reference tyre within one test cycle shall be less than or equal to 4 per cent.
(b) The arithmetic means of the average Braking Force Coefficients of the initial and the final braking test shall not differ by more than 5 per cent of the average of the two values:

where

 is the arithmetic mean of the average Braking Force Coefficients in the initial/final braking test of the reference tyre within a test cycle.

(c) The temperature-corrected average Braking Force Coefficients (BFC_ave,corr, see paragraph 3.2.1. of this Annex) as calculated from the initial and from the final braking tests of the reference tyre within a test cycle shall be not less than 0.57 and not greater than 0.79.
If one or more of the above conditions is not met, the complete test cycle shall be performed again.

For the candidate tyres (T):

The [DEL] coefficient of variation CV_BFC is calculated for each candidate tyre set. If one coefficient of variation is higher than 4 per cent, the data should be discarded and the test repeated for that candidate tyre set.

Calculation of adjusted average [DEL] Braking Force Coefficient

The [DEL] average Braking Force Coefficient 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.

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This adjusted average Braking Force Coefficient of the reference tyre BFC_adj(R) is calculated in accordance with Table 1 where   is the arithmetic mean of the average Braking Force Coefficients in the initial braking test of the reference tyre set (R_i) and  is the arithmetic mean of the average Braking Force Coefficients in the final braking test of the same reference tyre set (R_f) within the test cycle.

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Calculation of the wet grip index of the candidate tyre

The wet grip index [DEL]  G(T_n) of the candidate tyre T_n (n=1, 2, 3) is calculated as follows:

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 is the arithmetic mean of the average Braking Force Coefficients of the candidate tyre T_n within a braking test;

∆BFC(R)= BFC_adj(R)-BFC(R₀) 

BFC_adj(R)        is the adjusted average Braking Force Coefficient in accordance with Table 1;

BFC(R₀) = 0.68 is fixed as the Braking Force Coefficient for the reference tyre in the reference conditions;

∆ϑ=ϑ-ϑ₀

ϑ                      is the measured wet surface temperature in degrees Celsius when the candidate tyre Tn is tested;

ϑ₀                    is the wetted surface reference temperature for the candidate tyre according to its category of use as listed in Table 2;

∆MTD=MTD-MTD₀

MTD                is the measured macro texture depth in mm of the track (see paragraph 3.1.4. of this Annex);

MTD₀ = 0.8 mm is the macro texture depth of the reference track;

K_vehicle = 1.87 is a factor to grant consistency between previous calculation of the wet grip index and this one, and to ensure convergence between vehicle and trailer method and coefficients a, b, c and d are given in Table 2.

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[DEL] When a direct comparison between a candidate tyre and a reference tyre on the same vehicle is not possible the test method using a trailer or a tyre test vehicle (paragraph 4.2. of this Annex) shall be used.

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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.

The trailer or the tyre test vehicle shall be equipped with one place where the tyre can be fitted for measurement purposes, hereinafter called "test position", and the following accessories:

In the case of the one axle trailer, in order to reduce "pitch disturbance", 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".

In order to reduce "lateral disturbance", the trailer or the tyre test vehicle should be technically designed to minimize lateral displacement during the application of maximum braking force. Visual lateral displacement should be avoided during braking manoeuvre.

(a) The minimum frequency response shall be flat from 0 Hz to [DEL] 100 Hz within ±1 per cent full scale;

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.

The surface may be wetted from the track-side ("external watering") or by a wetting system incorporated in the test vehicle or the trailer ("self-watering").

If "external watering" is used, 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 braking lanes used, the water depth shall be between 0.5 mm and 1.5 mm, measured from the peak of the pavement.

For "self-watering" systems, the tow vehicle and trailer or the tyre test vehicle is 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.

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.

Tyre preparation and [DEL] stabilization and rims

The test tyre shall be mounted on a [DEL] rim [DEL]specified by a recognized tyre and rim standards organization as listed in Appendix 4 to Annex 6 to this Regulation. The rim width code shall not differ by more than 0.5 from the measuring rim width code.

The tyres should be stabilized in performance prior to testing, which means that no evolution of the μpeak value in test runs should be detectable; in any case there will be an ex-post verification according to paragraph 4.2.8.2. of this Annex. In all cases, tyre designed tread depth and designed tread block or rib integrity shall not change significantly with break-in, which means the pace and "severity" of the break-in needs to be carefully controlled to avoid such changes.

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The test load on the test tyre is (75 ± 5) per cent of the tyre load capacity.

[DEL] The test tyre set shall be installed on the measuring device and loaded to the specified test load according to paragraph 4.2.5.2. of this Annex.

For one-axle trailers, the hitch height and transverse position shall be adjusted [DEL]  in order to avoid any disturbance of the measuring results [DEL].

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.

For self-watering system, water shall be delivered to the pavement ahead of the test tyre approximately 0.5 s prior to brake application. [DEL]

The [DEL] brakes shall be activated within [DEL] an area of six (6) meters in the longitudinal direction and 0.5 meters in the transversal direction 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 test shall be run in the same direction as in paragraph 3.2.2. of this Annex. 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.

[DEL] Within the same test cycle, each test run of each braking test shall be made in the same direction and in accordance with paragraph 4.2.7.1. of this Annex. Several test cycles may be performed consecutively, where the final braking test of the reference tyre set of a test cycle may serve as the initial braking test of the reference tyre set for the next test cycle.
Up to three candidate tyre sets may be measured within the same test cycle, provided that the tests are completed within one day.

[DEL] Initial braking test of the reference tyre set (R_i): first, the reference tyre set is mounted and at least six (6) valid test runs shall be made in accordance with paragraph 4.2.7.1. above.

[DEL] Braking test of a candidate tyre set (T_n): the reference tyre set is replaced by a candidate tyre set and at least six (6) valid test runs with the candidate tyre set shall be performed.

After the braking test of the first candidate tyre set [DEL], up to two more candidate tyre sets may be measured.

Final braking test of the reference tyre set (R_f): the test cycle shall be closed by at least six (6) more valid test runs of the same reference tyre set as at the beginning of the test cycle.

(a) The run order for a test cycle with three candidate tyre sets [DEL] (T₁ to T₃) would be the following:

R_i-T₁-T₂-T₃-R_f

(b) The run order for a braking test [DEL] (consisting of two test cycles) of five candidate tyre sets (T₁ to T₅) [DEL] would be the following:

R_i-T₁-T₂-T₃-R_f/R_i-T₄-T₅-R_f

For each test run, the [DEL] 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.

f_h(t) is the dynamic braking force in real time, in N;

f_ν(t) is the dynamic vertical load in real time, in N.

The µ_peak coefficient of variation CV_µ is calculated as follows:

For the reference tyre (R):

(a) The coefficients of variation CV_μ of the initial and the final braking tests of the reference tyre within one test cycle shall be less than or equal to 4 per cent;
(b) The arithmetic mean of the peak braking force coefficients of initial and the final braking test of the reference tyre within one test cycle shall not differ by more than 5 per cent of the average of the two values: 

where
 are the arithmetic means of the peak braking force coefficients respectively in the initial and final braking test of the reference tyre within a test cycle;
(c) The temperature-corrected average peak braking force coefficients (μpeak,corr, see paragraph 3.2.2. of this Annex) as calculated from the initial and from the final braking test of the reference tyre within a test cycle shall be not less than 0.65 and not greater than 0.90.
If one or more of the above conditions is not met, the complete test cycle shall be performed again.

For the candidate tyre(s) (T_n):

The coefficient of variation of the peak braking force coefficient CVμ; is calculated for each candidate tyre. If one coefficient of variation is greater than 4 per cent, the data shall be discarded and the braking test repeated for this candidate tyre.

Calculation of the adjusted average peak braking force coefficient of the reference tyre  

This adjusted average peak braking force coefficient of the reference tyre  μ_peak,adj(R) is calculated in accordance with Table 3 where  is the arithmetic mean of the peak braking force coefficients in the initial test of the reference tyre (R_i) and  is the arithmetic mean of the peak braking force coefficients in the final test of the same reference tyre (R_f) within one test cycle.

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Calculation of the wet grip index of the candidate tyre

The wet grip index G(T_n) of the candidate tyre T_n (n = 1, 2, 3) is calculated as follows:

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 is the arithmetic mean of the peak braking force coefficients of the candidate tyre T_n within a braking test; Δμ_peak(R)=μ_peak,adj(R)−μ_peak(R₀)

μ_peak,adj(R) is the adjusted peak braking force coefficient in accordance with Table 3;

μ_peak(R₀) = 0.85 is fixed as the peak braking force coefficient for the reference tyre in the reference conditions; Δϑ=ϑ−ϑ₀

ϑ is the measured wet surface temperature in degrees Celsius when the candidate tyre Tn is tested;

ϑ₀ is the wetted surface reference temperature for the candidate tyre according to its sidewall marking as listed in Table 4;

ΔMTD=MTD−MTD₀

MTD is the measured macro texture depth of the track

MTD₀ = 0.8 mm is fixed as the macro texture depth of the reference track;

K_trailer = 1.50 is a factor to grant consistency between previous calculation of the wet grip index and this one, and to ensure convergence between vehicle and trailer method and

coefficient a, b, c and d are given in Table 4.