Point detail

[DEL]

 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.