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.

Minutes of the 51st Session of Informal Group on IWVTA held June 17, 2026. Proposed UN R0/09 series of amendments (IWVTA-51-03-rev.1) will be submitted to the 199th WP.29 session. Proposed amendments to General Guidelines on transitional provisions separating V.9. and V.9.bis from transitional provisions for XX series and making them independent as P.1. and P.2. applicable to all series will be submitted to WP.29 at its June session. OICA will look for concrete examples of transitional provisions. NL/RDW will submit a proposal on scheme and procedure for adding an attribute in DETA to indicate the latest series of amendments of approvals by the next session.

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.

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.

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.