Session report covering brainstorming on C3 test method development, including discussion of tyre segmentation priorities (segments A and C), methodological approaches (open road convoy, drum, accelerated, and single wheel trailer methods), testing capacity and timelines, funding needs, SRTT abrasion range expansion for C1 testing based on Korean data, C2 test campaign status, and TAPP participation criteria. Action items include simulation expert engagement, family approach feasibility review, SRTT range bracketing in UN R186, and drum method equivalence evaluation by JASIC.

The Task Force on Tyre Abrasion convened to address strategic and technical aspects of C3 heavy-duty commercial vehicle tyres. Discussion focused on harmonising market segmentation between European long-haul 22.5" tyres and Japanese all-position tyres under the 1958 Agreement, developing parallel indoor drum and on-road convoy test methods with technological neutrality, and addressing infrastructure funding and test method readiness by March 2030 GRBP adoption and June 2030 WP.29 adoption. Additional topics included Standard Reference Test Tyre incompatibility for trailer axles, simulation tools for tyre type extensions, regulatory definition of tyre type, novel hardware concepts, and the exclusion of retreaded tyres from initial UN R186 scope.

Record of Webex participants attending the TA-52-11 meeting over two days, listing participants’ names, affiliations, and join and leave times for each session.

Progress report on the Task Force on Tyre Abrasion covering February to October 2026. Work on UN Regulation on tyre abrasion for C1 tyres has concluded, with new UN R186 adopted at WP.29’s 199th session in June 2026, implementing a two-stage approach with initial application from 30 June 2028 and increased stringency from 30 June 2033. C2 test method development is ongoing with formal working document postponed to February 2027; C3 tyre work commenced with brainstorming session in October 2026 targeting working document in February 2027. The Task Force proposes conversion to an Informal Working Group.

Test findings from seven circuits in the Republic of Korea show that estimated SRTT17S abrasion levels at 20 °C exceeded the specified range of 25–75 mg/(kmt) at six of the seven circuits tested. These results indicate that conducting UN R186 tyre abrasion tests in the Republic of Korea on circuits that meet the current range would be challenging at present. The Republic of Korea suggests reviewing the suitability of the current circuit abrasion level range and commits to support efforts to establish a circuit abrasion level range applicable to circuits worldwide.