Proposal to amend UN Regulation No. 172 based on GRBP/2026/10 as amended by GRBP-83-15-Rev.1. Amendments include revised definition of supplier of tread in paragraph 2.2.; modification of paragraph 6.2. to require tyres to meet conditions in paragraph 6.2.1. or 6.2.2.; insertion of new paragraphs 6.2.2., 6.2.2.1., 6.2.2.2., and 6.2.2.3. establishing calculation methods for deformation potential and number of traction elements based on tyre class and nominal rim diameter; insertion of new paragraph 6.4.(a) for class C₁ tyres; renumbering of former paragraphs 6.