The SWG on data assessment defines its scope as organisational matters for the Confirmation plan 2026, data anonymisation, governance and data storage to be defined. Its mandate includes preparation of tyre selection for the Confirmation plan, informing and collecting information from candidate test facilities, organizing tyre availability and shipments, and preparing data for TAPP data assessment including data collection and compilation.

The agenda includes status updates on the Convoy Method Dual-Normalisation Framework, tyre abrasion timeline, and test method development for mileage potential metric, tread depth measurement, and C3 tyre abrasion. Action items include ETRTO uploading acceleration calculation examples to the TFTA wiki, TFTA reviewing the Gantt chart, and the SWG on data assessment redefining its scope by the 49th session.

• ETRTO to check feasibility to upload acceleration calculation examples on TFTA wiki,
• SWG on data assessment to define scope and mandate by 49th session,
• ITTAC proposal (TA-45-8v1) on Convoy Method Dual-Normalisation Framework deferred to next session,
• UTAC Gantt timeline reviewed; ETRTO regulatory experts reviewed proposal; technical experts review pending,
• Tyres Europe stated EU Tire Industry funded over 3m for C1 activities and will provide over 1m additional financing for C2 and C3 work; requested TFTA co-financing,
• EC will escalate request; JRC will participate with 2 convoys for C2 in 2026 and C3 in 2027,
• SWG on data assessment to define scope, mandate, and leader for next session,
• DEKRA presentation on vehicle impact with SRTT; vehicle effect neutralized through tyre rotation for correlation purposes,
• JRC service life update presented; analysis planned for end of 2026,
• ETRTO C2 test method development restarted May 2026; temperature impact observed for winter SRTT requiring 2026 workplan verification,
• GRBP Working Document delivery for C2 test method postponed to February 2027,
• ETRTO and JASIC C3 presentations deferred for comments next session.

Existing C1 tyre-abrasion test methods cannot be directly applied to C3 tyres because vehicles equipped with C3 tyres are used differently. Japan is developing a vehicle test method using WHVC mode and plans to develop a drum test method based on test conditions and results. Test conditions will convert vehicle driving conditions representing the world into indoor drum test settings. C2 test method uses driving mode based on WLTP with fixed test load details, with verification tests using reference tyres. For C3, driving modes and test conditions are under preliminary investigation, with verification tests to be planned.

DEKRA Test Center examined whether vehicles fitted with SRTT impact tyre abrasion rates. Tests DEKRA #104 and DEKRA #41 compared SRTT Summer as candidate against SRTT Winter as reference, with abrasion indices of 1.18 and 1.19 respectively, showing no vehicle impact. Tests DEKRA 8 and DEKRA 9 showed abrasion rates of 45.1 mg/km/T and 45.0 mg/km/T respectively with no difference despite different vehicles. A 2024 convoy test with two Golf vehicles fitted with identical SRTT Summer showed a difference of 1 gram cumulated weight loss after 7,962 km (0.07 mg/km/T). DEKRA concludes the impact on abrasion level of the reference vehicle using SRTT is low or very low.

The document presents a European heavy-duty vehicle and tyre market overview and C3 test method development status. The C3 tyre market is complex and diversified, with applications including long haul, regional, on/off road, winter, and urban use. A test concept has been developed focusing on road usage with 22.5" tyres, using convoys of up to four vehicles with defined acceleration standards, road distribution of 60% motorway and 40% regional roads, and tests per axle comparing candidate tyres to reference tyres. Current activities include assessment of reference tyres strategy, temperature sensitivity evaluation, and confirmation of test parameters for heavy trucks in N₃/O₃ configuration, with tests reaching 30,000 to 45,000 kilometres.

TA-48-02 updates TA-47-02. C2 tyre abrasion rate index vehicle method uses a convoy of up to 4 vehicles with single tyres, GVW up to 3.5T, FWD, loaded 60%–74% of tyre nominal load with 50/50 front/rear distribution. Test distance is 10000 km at 80% nominal pressure. Reference tyres use 2 sets of test runs with C2 candidate SRTT and existing C1 SRTTs. 2025 testing in 235/65R16C and 205/65R16C sizes showed C2 tyres sensitivity to temperature similar to C1 tyres. 2026 plan repeats and extends 2025 testing to confirm reference tyres strategy, assess temperature sensitivity and pressure impact, and define validation plan.

ETRTO proposed three ways to estimate service life (TA-36-04): tread depth measurements, initial tread depth and abrasion index, and tread mass. JRC presented a service life index (TA-32-04) based on tread depth measurements and conducted a preliminary assessment of the second concept. Service life is estimated by linear extrapolation to 1.6 mm from tread measurements at test start and end. The Service life index is calculated as the ratio of candidate to reference tyre service life. Next steps include confirming the equation for service life via tyre characteristics and clarifying which tyre characteristics are needed.

The agenda includes discussion of status of the work plan 2026 including the ITTAC proposal on tyre abrasion Convoy Method -Dual-Normalisation Framework (TA-45-08/Rev.1) and UTAC Tyre abrasion timeline Gantt (TA-46-03/Rev.1), development of the C1 tyre mileage potential metric and tread depth measurement prescription, and test method development status under C2 and C3.

The 47th session of the Task Force on Tyre Abrasion convened on 2 April 2026. The review committee prepared final consolidation of a new UN Regulation on Tyre Abrasion for WP.29. TFTA reviewed the workplan including data assessment, tyre batch use, and equivalence assessment governance. For C2, ETRTO presented findings on the vehicle test method at 10,000 km, while JASIC reported on indoor drum test development. Discussion on C3 Heavy-Duty Vehicle tyre applications was deferred. The next session is scheduled for 11 May 2026.

Proposal for a new UN Regulation on the approval of new pneumatic tyres of class C₁ conforming to UN R117 with regard to their tyre abrasion performance, excluding temporary-use spare tyres, tyres with rim diameter ≤13 or ≥25, competition tyres, tyres for vehicles of categories other than M₁–M₃, N₁–N₃, O₁–O₄, ice grip tyres, studded tyres, speed category less than 120 km/h, special use tyres, and road legal race tyres. Abrasion index limits are 1.00 for normal and snow tyres, with adjustments for specific groups. Approval requires marking with approval reference number and suffix (A1 or A2). Testing uses either vehicle test method on public open roads (~8000 km) or indoor drum test method (5044 km), with test facilities demonstrating equivalence per Annex 4. From 1 July 2028, stage 1 approvals required for new types; from 30 June 2030, all types. From 1 July 2033, stage 2 approvals required for new types; from 30 June 2035, all types. Until 1 July 2028, test results from tests performed