Proposal to amend GRBP-83-32-Rev.1 to ensure robust tyre abrasion measurements regardless of test method used. Amendments modify paragraph 6.1 to require test facilities demonstrate equivalence per Annex 4 procedure; insert paragraphs 12.8 and 12.9 deeming inter-facility campaign participants equivalent for C₁ tyres and allowing pre-regulation test data through 1 July 2028; insert Annex 3 paragraph 1.4 requiring inter-facility equivalence assessment; amend Annex 3 paragraph 2.8 with abrasion calculation equations including transfer function coefficient; insert test report items 1.1–1.4 in Appendices 2 and 6; and insert new Annex 4 establishing equivalence demonstration procedure for vehicle and indoor drum test facilities.

Proposal to establish a list of test facilities deemed equivalent pursuant to paragraph 12.8 of the draft UN Regulation on tyre abrasion. The list recognizes six foundational facilities that participated in the initial inter-facility campaign to develop abrasion limits for C₁ tyres. The facilities are: DEKRA Test Center SA (France, circuit); IFV (Germany, circuit); Link Engineering Company GmbH (Germany, circuit); Bridgestone Corporation (Japan, indoor drum); Sumitomo Rubber Industries, LTD. (Japan, indoor drum); and The Yokohama Rubber Co., Ltd. (Japan, indoor drum). These facilities generated foundational data used to define abrasion limits and are deemed equivalent for equivalence procedures under Annex 4.

This status report documents the Tyre Abrasion Task Force’s progress toward finalizing a draft UN Regulation on tyre abrasion for C1 tyres, as presented to GRBP 83 Part II. The task force pursued three workstreams: data analysis to reduce method uncertainty and inversion risk, editorial improvements to increase clarity of the draft regulation, and development of a method equivalence solution. GRBP 83 Part I achieved consensus on limit values and introductory dates but could not reach consensus on equivalence procedures between convoy and drum methods. Six informal documents (GRBP-83-32-Rev.1, GRBP-83-48-Rev.1, GRBP-83-49, GRBP-83-50-Rev.1, GRBP-83-53, and GRBP-83-55) addressing equivalence methodology, drum specifications, and code of practice frequency were submitted for potential adoption at the extraordinary GRBP 83 Part II session.

ETRTO comments on EC/JRC compromise proposal for Annex 4 tyre abrasion. ETRTO proposes an ALI range minimum of 0.5 as feasible and consistent with statistical distribution in MA results, rejecting the 0.7 range as unrealistic. For Generic Transfer Function gain, ETRTO recommends retaining a = 1.38 rather than the revised a = 1.45, to minimize rejection of good vehicle test results. ETRTO requests TFTA ToR amendment to confirm these conditions by February 2027 based on TA-45-9.

Proposal to amend document GRBP-83-32-Rev.1. Paragraph 1.2.9. amended to exclude special use Professional off-road tyres from scope. Paragraph 2.51. amended to read that the authority which has granted type approval may verify conformity control methods, with normal minimum frequency of verifications at least once every three years. Justification states special use tyres should be excluded as no limits will be established for them, and the three-year frequency aligns with Schedule 1 of the 1958 Agreement.

JATMA submitted this position on the draft UN Regulation for tyre abrasion at GRBP-83-54. JATMA requests adoption of the indoor drum test method under conditions equivalent to the vehicle test method for type approval. JATMA proposes that the Generic transfer function coefficient should be 1.14, calculated excluding tyre code 127 which exhibits significant variation. JATMA also proposes that the abrasion index range for tyres used in the Annex 4 procedure should be set between 0.4 and 0.5, and that no restrictions should be imposed on baseline test facilities when applying the Specific Transfer Function.

Proposal to amend document GRBP-83-32-Rev.1 to renumber Paragraph 6.1. as 6.1.1., renumber current Paragraph 6.1.1. as 6.1.2., introduce new paragraph 1.4. to Annex 3 Introduction, amend paragraph 2.8. with detailed abrasion index and level calculation equations, renumber items in Appendix 2, delete item 1.3. from Appendix 2, and amend item 1.3. in Appendix 6 to clarify transfer function applicability between circuit and drum test facilities.

Proposal to amend para. 2.18. to update the year reference in standard F2493 from 24 to 26, amend paras. 6.6. and 6.7. to change “classified” to “categorized”, revise tread depth and void to fill ratio requirements for class C1 special use tyres, restructure requirements for professional off-road tyres with subsections for each class, amend Annex 3 para. 4.2.2. to correct the measurement unit of coefficient K1 to dB(A), amend Annex 3 Appendix 1 Part 2 item 3.1. to update the ISO 10844 year reference from 2014 to 2021, and amend Annex 7 Appendix 3 Item 5 to enable SRTT weighted average to be reported for each candidate in the test results table.

Proposal to amend para. 2.18. to change the reference year from 24 to 26 for standard F2493, add new para. 2.21. defining “road legal race tyre,” add new para. 4.2.8. requiring the inscription “RLR” for road legal race tyres, insert new footnote 12 on marking height, renumber current footnote 12 to footnote 13 and amend its text, amend para. 5.4.1. to reference footnote 13, add new para. 6.9. establishing requirements for road legal race tyre classification, add new item 4.3. to Annex 1, amend para. 6.7. to change “classified” to “categorized,” amend Annex 3 para. 4.2.2. tables to change K1 unit from C to dB(A), amend Annex 3 Appendix 1 Part 2 item 3.1. to update ISO10844 reference from 2014 to 2021, and amend Annex 7 Appendix 3 Item 5 table to enable reporting of SRTT weighted average for each candidate.

Proposal to insert paragraphs establishing references to Software Identification Number definitions in Consolidated Resolution R.E.3 Annex 7 para. 2, insert paragraphs requiring manufacturers to provide Technical Services with information on hardware and software influencing performance, insert paragraphs allowing vehicle manufacturers to apply for new approvals to differentiate software versions for registered vehicles from those for new vehicles with duplication of tests avoided where possible, amend production discontinuation provisions to clarify that production is not considered definitively discontinued if manufacturers intend to obtain subsequent extensions for software updates of registered vehicles, and amend approval communications to include additional information regarding software identification and software updates in UN Regulations 51, 64, 138, 141, 142 and 165, as presented in document GRBP-83-36 and implementing Revision 8 to Consolidated Resolution No. 3 (WP.29/2025/147).