Proposal to revise the generic transfer function coefficient based on 2026 test campaign results, revise the ALI range for specific transfer function assessment, integrate assessment criteria for both test methods, and delete the coefficient of determination (R²) requirement since delta ALI and RMSE are sufficiently tight for assessment.

Draft agenda for the 54th session of TFTA on 9 November 2026. The meeting will address finalising C1 and C2 provisions for GRBP Working Document 85th session, the status of an ongoing test campaign, and a follow-up brainstorming session. Action items include requesting a French representative to join the next meeting and reviewing possibilities for further defining tyre types by grouping them and optimizing the number of physical tests through simulations and models. The agenda also covers funding and resource allocation for technical activities.

Minutes from the Task Force on Tyre Abrasion 53rd session held 29 October 2026. The session reviewed TADG status on drafting C1 and C2 provisions for GRBP Working Document 85th session and discussed amendment proposals to UN R186. TFTA agreed with TADG proposals including removal of special use tyres from AICT requirements, keeping drum abrasion level range as currently defined, and placing sandpaper surface replacement recommendation frequency in square brackets. TFTA also agreed with ETRTO proposals for C1 vehicle method amendments to paragraphs 1.6.2, 1.6.8, 1.6.9, 1.6.4.1, 1.7.4.1, and 7.4, and for C2 vehicle method amendments to paragraphs 1.9.2, 1.6.2, 1.10.4.2, 1.8.2.1, 1.8.2.2, and 1.6.4. GRPE endorsed the request to elevate TFTA to an IWG TA and address the request to WP.29 session 200 in November 2026.

Study evaluating the validity of the current recommendation in Annex 3 Appendix 5 for sandpaper surface replacement interval based on running distance by examining test results exceeding 20,000 km. Testing nine consecutive runs on #80 grit sandpaper without replacement over 45,000 km total distance using new tyres for each run. Surface roughness measured by MPD and micro roughness showed no significant change and satisfied requirements in Paragraph 2.4.2.3. SRTT17S abrasion level remained above specification limits. Reproducibility of Abrasion Index was maintained when compared with Market Assessment results. Proposes extending replacement interval from 20,000 km to 30,000 km for 2-position drums and from 40,000 km to 60,000 km for 1-position drums.

Minutes of the 50th session of TFTA held on 6 July 2026. TFTA approved previous meeting minutes and agenda. The SWG Secretary updated on workplan 2026 organizational matters. ETRTO reported two best practice sessions on open road convoy method on 26 June and 3 July, with JATMA organizing a drum method session on 7 July. JASIC provided comments on the UTAC timeline Gantt; TFTA agreed to simplify subject lines 13-15, keep the February 2027 timeline with a review note after summer 2026, and retain line 24 with an indicative note. Action items assigned include preparing a revised Gantt and contacting test facilities on tread depth measurements. Discussion covered C1 mileage potential metric development, C2 test method status and equivalence framework for C2 tyres, and C3 test method development with a brainstorming workshop planned for 8-9 October in hybrid format. TFTA agreed to prepare Supplement 1 to UN Regulation No. 186 with submission deadline week of 9 November 2026.

Draft minutes of the 51st session of the Task Force on Tyre Abrasion held 25 August 2026. The session covered status of the 2026 workplan organizational matters, including TAPP participation, equivalence evaluation of test facilities, and best practice meetings. The TFTA agreed to a consolidated Gantt chart with versioning and regular review. A hybrid brainstorming workshop on the C3 test method is scheduled for 8-9 October 2026 in Brussels and remotely. The Co-chairs will prepare a revised TFTA status report for GRBP’s 84th session.

Status report on the Tyre Abrasion Drafting Group’s progress across sessions 14–16 in 2026. Work includes proposed editorial amendments to UN R186 covering removal of special use tyre references, alignment of symbols between vehicle and drum test methods in Annex 3, updates to ASTM standard references, clarification of introductory provisions, reordering of vehicle requirement paragraphs, splitting of vehicle and circuit requirement paragraphs, updates to test load definition, reworded alternative test program description, removal and correction of duplicate drum control system requirements, and sandpaper surface replacement provisions. Circuit and drum abrasion level ranges require further review by the Task Force on Tyre Abrasion.

Agenda for the 53rd TFTA session on 29 October 2026. Items include approval of previous meeting minutes, outcome from GRPE 95th session, status of TADG drafting C1 and C2 provisions, ETRTO proposals for UN R186 updates, C1 circuit SRTT abrasion level range, C2 test campaign status, C3 brainstorming on virtual testing and tyre type definition optimization, and funding and resource allocation discussion.

Proposal to suppress the loading restriction to 85% of vehicle payload, allow several propulsion energy converters, allow mixing different transmission architectures, include circuit abrasion level measurement possibilities for snow tyres not measuring Severe Snow Tyres, and establish new circuit abrasion level limits based on 17 circuits in the 2026 Confirmation plan. ETRTO is testing acceleration correction, fully loaded vehicles, different energy converters and transmission architectures, alignment specifications for various vehicle types, and load distribution management to reduce test uncertainties and improve method efficiency. An informal document will be proposed in January 2027.

Update proposal for UN R186 to modify load distribution in para. 1.6.2 to apply only to C₁ tyres and add minimal ballast requirement for C₂ tyres, update temperature ranges in para. 1.10.4 for normal and snow tyres, and develop alignment prescriptions for C₂ tyres. The proposal describes a test concept using convoys of up to 4 vehicles with single tyres up to 3.5T GVW under controlled driving conditions to determine tyre abrasion level index. SRTT usage strategy and market assessment to be finalized following temperature testing results.

Review of UN R186 for opportunities to improve wording.

Proposal to modify the equivalence procedure for tyre test facilities to include circuits meant for severe snow tyres and snow tyres not classified as severe snow tyres, revise the selection criteria for exercise tyres to require an ALI range of at least 0.40 units with approximately even distribution and a specified ratio of normal tyres to snow tyres, and restrict equivalence of facilities designed for testing only normal tyres or specific snow tyre categories to the corresponding tyre category.

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.

Proposal to amend para. 8.2. to specify that conformity control methods should take into consideration production volumes of the type of tyre at each manufacturing facility with a normal minimum frequency of at least once every two years, and add para. 8.3.3. to establish a minimum frequency of verification tests once every three years, aligning with Schedule 1 of the 1958 Agreement.

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.