Part B: Wet grip classesU.K.
[F11. The wet grip class of C1 tyres must be determined on the basis of the wet grip index ( G ) according to the ‘A’ to ‘G’ scale specified in the table below, calculated in accordance with point 3 and measured in accordance with Annex V. U.K.
Textual Amendments
F1 Substituted by Commission Regulation (EU) No 1235/2011 of 29 November 2011 amending Regulation (EC) No 1222/2009 of the European Parliament and of the Council with regard to the wet grip grading of tyres, the measurement of rolling resistance and the verification procedure (Text with EEA relevance).
2. The wet grip class of C2 and C3 tyres must be determined on the basis of the wet grip index ( G ) according to the ‘A’ to ‘G’ scale specified in the table below, calculated in accordance with point (3) and measured in accordance with ISO 15222:2011 whereby the following Standard Reference Test Tyres (SRTT) must be used: U.K.
(i)
for C2 tyres, the SRTT 225/75 R 16 C, ASTM F 2872-11;
(ii)
for C3 tyres having Nominal Section Width lower than 285 mm, the SRTT 245/70R19.5, ASTM F 2871-11;
(iii)
for C3 tyres having Nominal Section Width greater than or equal to 285 mm, the SRTT 315/70R22.5, ASTM F 2870-11.
3. 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 tyres | C2 tyres | C3 tyres | |||
|---|---|---|---|---|---|
| G | Wet grip class | G | Wet grip class | G | Wet grip class |
| 1,55 ≤ G | A | 1,40 ≤ G | A | 1,25 ≤ G | A |
| 1,40 ≤ G ≤ 1,54 | B | 1,25 ≤ G ≤ 1,39 | B | 1,10 ≤ G ≤ 1,24 | B |
| 1,25 ≤ G ≤ 1,39 | C | 1,10 ≤ G ≤ 1,24 | C | 0,95 ≤ G ≤ 1,09 | C |
| Empty | D | Empty | D | 0,80 ≤ G ≤ 0,94 | D |
| 1,10 ≤ G ≤ 1,24 | E | 0,95 ≤ G ≤ 1,09 | E | 0,65 ≤ G ≤ 0,79 | E |
| G ≤ 1,09 | F | G ≤ 0,94 | F | G ≤ 0,64 | F |
| Empty | G | Empty | G | Empty | G] |