Discussion document presenting general considerations for a C3 tyre abrasion test method. Topics addressed include objectives for reducing C3 tyre wear, quantification of C3 abrasion relative to overall and C1 abrasion, C3 tyre life including retreading effects, operational factors influencing tyre wear such as fleet optimization and load management, and environmental concerns regarding C3 microplastics and chemical requirements.

ETRTO analysis of the European C3 tyre market segmentation, emission levels per tyre segment, and vehicle configurations. ETRTO recommends focusing on Segment A (Heavy Duty Tyres 22.5 for Long haul and regional usage), which captures approximately 71% of wear emissions. ETRTO evaluated five alternative methods to the convoy method using criteria including time to market, representativeness, regulatory suitability, and cost. ETRTO concludes the convoy method focusing on Segment A is the only feasible method given the mandated timeline, despite drawbacks including test duration and environmental impact.

Presentation of fka’s tyre technology division capabilities in testing, simulation and research. Describes fka’s collaboration with ZF on developing a C3 tread wear drum test rig to be operational in Q1 2027. Outlines fka’s offer to support joint development and validation of C3 drum abrasion methodology with TFTA members, requiring funding commitments or test workload from interested partners. Discusses technical considerations including drum curvature effects, surface texture replication, testing capacity estimates, and environmental impact of convoy versus laboratory testing methods.

Presentation of a concept for accelerated tire wear testing using a standard truck with independent steering on left and right sides. The method employs steering actuators from existing steered rear axles to create longitudinal and lateral slip, accelerating tire wear while maintaining representative behavior. Reference tire and test specimen can be mounted on separate axles to compare wear rates.

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.

Presentation of ZF’s tread wear tester for C3 tires, available for operation in Passau until at least September 2029. ZF intends to operate the test rig in cooperation with fka for method development, validation, and correlation with on-road testing. The machine will be fully operational at ZF with climate chamber, cooling and filtering, and powder supply, with target operational date Q1 2027. FKA plans to acquire the machine and operate it at the ZF site for the first few years.

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.

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.

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.

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.

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.

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.

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.

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 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.

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.

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.