13. The expert from ETRTO proposed a correction to the 04 series of amendments to UN Regulation No. 117 (GRBP-82-27). GRBP adopted the proposal but agreed not to submit it immediately to WP.29 and AC.1, awaiting other amendment proposals to the same series of amendments.

16. The Co-Chairs of TF TA presented their proposals for a new UN Regulation on tyre abrasion, together with the corresponding amendments to UN Regulation No. 117 (ECE/TRANS/WP.29/GRBP/2025/27 as amended by GRBP-82-29 and ECE/TRANS/WP.29/GRBP/2025/28). GRBP noted that both ‘indoor drum’ and ‘on-road vehicle’ test methods were included on equal footing in the draft new UN Regulation, but a low level of correlation between the methods had been observed from the market assessment data, with much better results from the dedicated correlation-validation (COVA) testing campaign. GRBP also noted that the limit values for tyre abrasion remained to be determined for both Stages 1 and 2.

17. The expert of ETRTO highlighted the position of the EU tyre industry on setting the abrasion limits (GRBP-82-24, GRBP-82-25) and proposed modifications to the TF TA package of amendments (GRBP-82-37).

18. Several experts expressed the view that the drum method was not yet ready for adoption, given a low reproducibility of results in different laboratories and the need for further validation. They suggested to start first with the on-road method and add the drum method at a later stage. Some other experts were in favour of including both methods in the new Regulation from the beginning. Following an in-depth discussion on the methods and tyre abrasion limits, GRBP realized that it would not be possible to reach a consensus at this session and agreed to finalize the amendment package at the next meeting. GRBP invited experts from all Contracting Parties to actively participate in the coming TF-TA meetings to contribute to reaching a compromise at the next session.

19. The expert from India suggested to explicitly indicate that the draft new UN Regulation would apply to radial tyres only and not to bias-ply tyres.