Proposal to revise the limits for rolling resistance and wet grip, to address tyres for vintage vehicles, to revise the definition for special-use C1 tyres, and 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. The proposal also introduces the k_worn 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), provisions to allow the type approval of special use tyres that fulfil the requirements for snow performance as laid out in Annex 7, and a new definition of traction elements to characterize traction tyres.

Proposal to introduce provisions to allow type approval of special use tyres that fulfil the requirements for snow performance as laid out in Annex 7, to improve precision of the test procedures for measuring the wet adhesion of tyres in a worn state by using a moulded SRTT16 reference tyre (instead of a buffed tyre), to introduce new transitional provisions related to this change, to extend corrections already made to the 02 series to the 03 series and make additional editorial corrections, and to define the range for tyre inflation vis-à-vis rim size to reduce uncertainties in measuring tread depth. The proposal introduces the tyre reference F3611-22 per document GRBP/2023/2 submitted to the January 2023 session of GRBP.