UN R117: Proposal for a 04 series of amendments
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Proposal from the Worn Tyres working group to set the wet grip index threshold at 0.80 for class C1 tyres with a nominal aspect ratio equal to or less than 40, a section width equal to or higher than 235 mm and suitable for speeds equal to or greater than 300 km/h and for class C1 all terrain and special use tyres (see GRBP-75-27, slide 6). The proposal also introduces the kworn factor in a new para. 3 in Annex 9 to address wet grip of C2 and C3 tyres in a worn state (see GRBP-75-26-Rev.1 for concept).

Reference Number: GRBP/2022/23
Date: 16 June 2022
Proposal Status: Formal GR review
Related Documents:
GRBP-75-26/Rev.1 | UN R117: Presentation on the concept for addressing wet grip on worn tyre requirements for C2 and C3 tyres
GRBP-75-27 | UN R117: IWG Wet Grip on Worn Tyres - status report
WT-44-06/Rev.1 | UN R117: Draft text for an informal document to amend document GRBP/2022/23