For the reference tyres [DEL]:

(a) The coefficient of variation CVBFC 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 (BFCave,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.

 a5c0
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