The Tyre Abrasion Task Force has completed tyre selection for the Confirmation plan 2026 and informed candidate test facilities. Tyre availability and shipments remain ongoing. Data collection and compilation for data assessment awaits test commencement. The SWG on Data Assessment has agreed to transfer discussions regarding exclusion criterion for high variability tyres and acceleration corrections to TAPP upon its resumption of meetings.

The document presents reflections on equivalence criteria for C2 tyres under Annex 4. C1 and C2 protocols are expected to remain very similar, with most changes having no impact on ALI and facility correlation. Key differences include tyre load and inflation pressure specifications. The main hypothesis states that if final C2 methods remain closely aligned to C1 methods, the existing equivalence framework for C1 could be maintained and extended to C2 testing, with already equivalent facilities receiving automatic equivalence or minor validation, and new facilities requiring amendment of Annex 4 to accept a mix of C1 and C2 tyres for demonstration of equivalence.

Task Force Data Analysis held an online meeting on 7 July 2026. The group discussed database analysis, including insufficient data for higher performance and acceleration, and agreed that more data are needed. When new data are generated, operation conditions should focus on higher performances covering the ASEP range, higher accelerations up to and exceeding 5 m/s, pass-by runs with gear shifting, and low speed measurements in the UN R117 AVAS control range. The group reviewed proposals to the TF-Editing based on draft UN R51.04 and agreed some changes, with review results to be uploaded as Rev.1. A question regarding the phrase “but no more than 2.0 m/s” in paragraph 3.1.2.1.4.3 regarding vehicles with only one gear ratio was noted as issue #23 pending further review.

Minutes of the 75th session of the Informal Working Group WGWT held 16 June 2026 on-line. The agenda was adopted. Previous meeting minutes from the 73rd session (31 March 2026) and 74th session (19 May 2026) were adopted. WTPP secretary updated on testing activities status per document WT-75-2. ETRTO stated the agreed number of tests was a statistical minimum and IWG WGWT conclusions to GRBP must be based on complete test results. IWG WGWT agreed to await WTPP conclusions on outliers before deciding whether to keep the current number of tests or make additional tests. The co-chair stated a status report must be prepared for GRBP 84th session (September 2026) and suggested an IWG WGWT meeting days before GRBP. Next IWG WGWT meeting scheduled for 28 August 9:00–10:00 CET.

The Worn Tyres Post-Processing task force completed data collection for 3PMSF and Normal tyres, each with 57 samples representing 100% of target. Ongoing activities include outliers analysis of the 3PMSF and Normal cluster and post processing of the data conclusions.

The agenda includes discussion of the status of the 2026 workplan (TA-51-03), UTAC tyre abrasion timeline Gantt chart (TA-51-02), development of mileage potential metric and tread depth measurement prescription (TA-51-5), test method development status, preparation of TFTA status report for GRBP 84th session (TA-51-04), and next meeting(s).

Current work involves data-collection preparations for TAPP data assessment using an updated template. Some testing has already begun.

The Task Force on Tyre Abrasion completed work on the UN Regulation on tyre abrasion for C1 tyres and is launching C2 work. UN R186 on tyre abrasion for C1 tyres was adopted at WP.29’s 199th session in June 2026, with a two-stage implementation approach beginning 30 June 2028. C2 test method development is ongoing with an Informal Document to be submitted to GRBP in February 2027 instead of September 2026. C3 tyres will undergo a brainstorming session in October 2026 before commencing testing.

A two-day brainstorming session will be held in Brussels during October 8-9, 2026. The session aims to address the lack of a concrete test method solution for C3 tyre abrasion by reflecting on innovative test method ideas not bound to existing C1 and C2 approaches, brainstorming phased introduction of tyre abrasion requirements across C3 tyre segments, and optimising resources to reduce testing burden. Day 1 will address C3 market complexities and tyre segmentation across duty cycles; Day 2 will cover methodological ideation, funding and resource allocation, and review of the C2 test campaign before the February 2027 working document.

Proposals for earlier series of amendments those may be used in certain country
where R156-01 is required. The provisions regarding provision of information on hardware and software relevant to approval testing are moved to the section related to specifications and/or tests as instructed in R.E.3. and the amendment made by WP29-197-06 is reflected.

Draft agenda of the 76th session of the Informal Working Group WGWT scheduled for August 28th, 2026 on-line. The agenda includes welcome and opening remarks, adoption of the agenda, adoption of the minutes of the 75th session of 16 June 2026, review of work plan 2025-2026 for C1 tyres, review of IWG WGWT status report for GRBP 84th session of September 2026, and next meetings.

The IWG for Wet Grip on Worn Tyres reports progress on evaluating methods for preparing tyres of Class C1 to be tested in worn state at type-approval, defining test conditions and methods, establishing type-approval thresholds for wet grip performance, and addressing requirements for classes C2 and C3. Test Campaign Stage 1 assesses test procedure precision per GRBP-80-11, with normal and 3PMSF tyres completely tested at 13 test centres. Outliers analysis and KPI target confirmation are ongoing. Stage 2, if needed, is planned for 2026-2027.

Proposal to amend para. 1.1. to clarify that retreaded pneumatic tyres of Classes C₁, C₂ and C₃ are subject to snow performance requirements and C₂ and C₃ tyres to traction tyre classification, and insert new para. 1.2. to establish that Contracting Parties shall issue or accept approvals to snow performance of retreaded tyres of Classes C₁, C₂ and C₃ and/or the classification as traction tyres for retreaded tyres of Classes C₂ and C₃.

Proposal for Supplement 3 to the original version of UN Regulation No. 172 to amend para. 1.1. to clarify that this Regulation applies to retreaded pneumatic tyres of Classes C1, C2 and C3 with regard to their snow performance and for C2 and C3 tyres with regards to their classification as traction tyre, and insert new para. 1.2. to state that Contracting Parties shall issue or accept approvals to snow performance of retreaded tyres of classes C1, C2 and C3 and/or the classification as traction tyres for retreaded tyres of classes C2 and C3.

Proposal to improve the readability of the text by using only the wording “run flat tyre”, mentioning the alternative wording “self supporting tyre” in a note and restricts the use of ZR and ZRF marking to the tyres suitable for speeds greater than 300 km/h.

Proposal introduces the definition of “dual fitment” which is missing in the current text and improves the readability of the text by using only the wording “dual fitment”, mentioning the alternative wording “twin fitment” in a note.
Solves problem of type approving LT tyres with load-capacity index greater than or equal to 122 and suitable for dual fitment.

Proposal to clarify that an extended mobility tyre shall not be retreaded without being marked with the EMT symbol to avoid the mix up on the same axle with a tyre of radial structure not featuring extended mobility capabilities

Existing transitional provisions do not address the issue of retreaded tyres produced in accordance with the applicable requirements before 1 September 2028. Thus, a significant quantity of retreaded tyres will stay stocked within the different stages of the distribution channels.

Proposal to solve the discrepancies between the test report format and the description of the test method for C2 and C3 tyres.

Proposal replaces the GRBP2026/26

Road legal race tyres are currently defined in the new UN R186 on abrasion but fall out of its scope. Considering that the new UN R186 on abrasion applies only to tyres that conform to UN Regulation No. 117., it is proposed to replicate therein the definition, the marking and the requirements of road legal race tyres by adding the new paragraphs 2.21., 4.5. and 6.9.