33. The co-chairs of TFTA introduced GRBP-83-44. Following the introduction of GRBP-83-30, GRBP-83-32, GRBP-83-34, GRBP-83-35, GRBP-83-37, GRBP-83-38, GRBP-83-40, GRBP-83-45, GRBP-83-46, GRBP-83-47 by their respective submitters, The Chair invited GRBP and TFTA to consider the various options to solve remaining open points, especially with respect to equivalency between the two test methods.
34. The co-Chairs of TFTA introduced the latest version of GRBP-83-32-Rev.1. Stakeholders exchanged views on some elements of the proposal, such as extra allowance for Ultra High Performance (UHP) tyres on one hand and Low Load Index (LI) tyres on the other hands.
35. The representative of Japan commented that, although the correlation between the two test methods had already been made clear from the verification results to date, the discussion was returning to a comparative approach, and that it was inappropriate to proceed based on a specific proposal.
36. Following additional discussions, the representative of the EC informed that good progress were made to finalize the UN Regulation on tyre abrasion. He nonetheless reckoned the work on equivalence would not be completed during this session, and said he could not support adoption of a full proposal at this session. He invited GRBP to find a way forward to try and find a solution to finalize the proposal.
37. The Chair proposed to use part of the forthcoming 94th session of the Working Pary on Pollution and Energy (GRPE) on 17 March 2026 morning to finalize and adopt the TFTA proposal. He also proposed to freeze the content of the main body of the proposal included in GRBP-83-32-Rev.1 and not to re-open the content should GRBP agree to re-convene on 17 March.
38. GRBP agreed to freeze the content of GRBP-83-32-Rev.1, and agreed to have a second part of the 83rd session of GRBP on the 17 March 2026 to finalize the equivalence methodology between road convoy and drum tests.
39. At the beginning of the second part of the 83rd session of GRBP (held on the morning of 17 March 2026), the Co-Chairs of TFTA introduced GRBP-83-51-Rev.1. The representative of ETRTO introduced GRBP-83-52 and GRBP-83-53. The representative of JATMA introduced GRBP-83-54.
40. The representative of the EC introduced GRBP-83-49 and GRBP-83-50-Rev.1. The representative of ETRTO asked where GRBP-83-50-Rev.1 would be hosted. The secretariat said the document would be uploaded under “documents for reference only (GRBP)” section of the UNECE website . The representative of the EC added that the information in GRBP-83-50-Rev.1 would not change, and that another list would be created at a later stage for new equivalent facilities.
41. The representative of ETRTO introduced GRBP-83-55-Rev.1. The representative of JATMA supported GRBP-83-55. GRBP endorsed the content of GRBP-83-55-Rev.1 after a small change during the session.
42. As full package to get a complete new UN Regulation on tyre abrasion, the Chair proposed to adopt GRBP-83-32-Rev.1, together with GRBP-83-49, GRBP-83-50-Rev.1, GRBP-83-53 (as modified during the session) and GRBP-83-55-Rev.1.
43. The representative of Japan still had reserves on some of the outcomes such as the equivalency methodology but did not want to oppose the adoption of the new UN regulation and agreed to move forward in the spirit of compromise, on the condition that discussions continue at TFTA in the future. He invited all engaged stakeholders to continue working on improving the UN Regulation as more tests results became available.
44. The representative of Korea supported the development of an internationally harmonized tyre abrasion test method at WP.29, aiming to reduce microplastics and particulate emissions from tyres. He emphasized that the methodology should reflect real-world driving conditions, be practically applicable across different countries, and allow authorities to conduct independent compliance verification.
45. While real-road convoy testing combined with inter-laboratory equivalence is considered the ideal approach, the representative of Korea highlighted practical limitations in global implementation, including logistical and regional constraints. In this context, Korea considered the drum test a practical and effective alternative, particularly for countries where real-road testing was difficult. The SRTT-based transfer function proposed by JASIC is supported as a reasonable method for ensuring equivalence, while the conservative approach suggested by ETRTO can serve as a transitional solution.
46. In the long term, the representative of Korea acknowledged the need for a global framework for inter-laboratory validation. Meanwhile, he reminded it was important that authorities retained flexibility to use either test method, with compliance recognized under the method applied.
47. The representative of the UK thanked all involved stakeholders for the good balance achieved and the spirit of compromise. He supported the adoption of the package proposed by the Chair.
48. The representative of France, Germany and The Netherlands supported the proposed package.
49. The representative of ETRTO reminded the long journey to get to this proposed package, recapping all the work that had been done to develop this proposal, sometimes with politics interfering with the technical work. He also invited to improve the governance of TFTA, for example by publishing the minutes of the TFTA meetings in a timely manner to be considered by all interested parties.
50. He said including two testing methods was a challenge but would also be a big added value for the future. He highlighted that the transfer function gain revision should be addressed in the next supplement to the new UN Regulation, called for revisiting Annex 4 after the finalization of testing included in the workplan 2026. He finally invited to revise the Terms of Reference of TFTA by February 2027 for the deliverables of the confirmation plan 2026.
51. The representative of OICA showed appreciation for the work delivered, and acknowledged the need for further improvements to the methodology. He highlighted the importance of having 2 test methods available to reduce any potential testing bottlenecks.
52. GRBP adopted the package as proposed by the Chair (GRBP-83-32-Rev.1, together with GRBP-83-49, GRBP-83-50-Rev.1, GRBP-83-53 (as modified during the session) and GRBP-83-55-Rev.1) and requested the secretariat to submit it to WP.29 and AC.1 for consideration and vote at the June 2026 sessions as draft new UN Regulation No. [XXX] on the uniform provisions concerning the approval of tyres with regard to abrasion performance.
53. The representative of ETRTO highlighted potential editorial and inconsistency issues when combining GRBP-83-32-Rev.1 with GRBP-83-49. GRBP invited the secretariat to create a group of interested parties to work on consolidating the adopted package before submission toWP.29. The representative of France, Japan, The Netherlands, the UK, the EC and ETRTO volunteered to support compiling a consolidation version of the draft UN regulation on tyre abrasion to be submitted to the June 2026 session of WP.29.