ANNEX IU.K.TESTING, GRADING AND MEASUREMENT OF TYRE PARAMETERS

Part A: Fuel efficiency classes and rolling resistance coefficientU.K.

The fuel efficiency class shall be determined and illustrated on the tyre label on the basis of the rolling resistance coefficient (RRC in N/kN) according to the ‘A’ to ‘E’ scale specified in the table below and measured in accordance with Annex 6 to UNECE Regulation No 117 and aligned in accordance with the laboratory alignment procedure set out in Annex V.

If a tyre type belongs to more than one tyre class (e.g. C1 and C2), the grading scale used to determine the fuel efficiency class of that tyre type shall be that which is applicable to the highest tyre class (e.g. C2, not C1).

C1 tyresC2 tyresC3 tyres
Fuel efficiency class RRC in N/kN RRC in N/kN RRC in N/kN
A RRC ≤ 6,5 RRC ≤ 5,5 RRC ≤ 4,0
B 6,6 ≤ RRC ≤ 7,7 5,6 ≤ RRC ≤ 6,7 4,1 ≤ RRC ≤ 5,0
C 7,8 ≤ RRC ≤ 9,0 6,8 ≤ RRC ≤ 8,0 5,1 ≤ RRC ≤ 6,0
D 9,1 ≤ RRC ≤ 10,5 8,1 ≤ RRC ≤ 9,0 6,1 ≤ RRC ≤ 7,0
E RRC ≥ 10,6 RRC ≥ 9,1 RRC ≥ 7,1

Part B: Wet grip classesU.K.

1.The wet grip class shall be determined and illustrated on the tyre label on the basis of the wet grip index (G) according to the ‘A’ to ‘E’ scale specified in the table below, calculated in accordance with point 2 and measured in accordance with Annex 5 to UNECE Regulation No 117.U.K.

2.Calculation of wet grip index (G)U.K.

G = G(T)-0,03

where:

G(T) = wet grip index of the candidate tyre as measured in one test cycle

C1 tyresC2 tyresC3 tyres
Wet grip class G G G
A 1,55 ≤ G 1,40 ≤ G 1,25 ≤ G
B 1,40 ≤ G ≤ 1,54 1,25 ≤ G ≤ 1,39 1,10 ≤ G ≤ 1,24
C 1,25 ≤ G ≤ 1,39 1,10 ≤ G ≤ 1,24 0,95 ≤ G ≤ 1,09
D 1,10 ≤ G ≤ 1,24 0,95 ≤ G ≤ 1,09 0,80 ≤ G ≤ 0,94
E G ≤ 1,09 G ≤ 0,94 G ≤ 0,79