DASHBOARD CONVOY MARKET ASSESSMENT C1

Proposal to amend ECE/TRANS/WP.29/GRBP/2025/27

Proposal for acceleration calculation based on GNSS data to amend document GRBP/2025/27.

Proposal to amend GRBP/2025/27 based on GRBP-83-32. Modifications to Annex 3 revise the abrasion index calculation methods for both vehicle test and indoor drum test methods. The abrasion margin (Amargin) is redefined in two stages accounting for evolution of measurement methods and tyre technology, with different values for normal, snow, and special use tyre categories. Amargin allowances for specific tyre groups, including severe snow conditions tyres, reinforced tyres, and tyres with nominal aspect ratio ≤40, are defined as cumulative additions to the base Amargin value.

ETRTO presents a temporary conservative transfer function for tyre abrasion testing with a gain value of 1.5, designed to minimize drum inversion risk and reduce rejection risk while enabling coexistence of Indoor Drum Method and Outdoor Vehicle method at GRBP 83rd session. The transfer function, based on TA-40-2 data analysis, will be revised following a 2026 workplan before a more relevant solution in Supplement 1 to UNRxxx at GRBP 84th session.

ETRTO presents its position on remaining open points for C₁ tyre abrasion limit settings, reminding positions from GRBP-82-24. Key points include: inclusion of two assessment methods; limit settings proposing approximately 23% market removal by Euro7 application timeline and additional 13.5% removal five years later; exclusion of C₁ special use tyres representing 0.7% of EU market; retention of 0.1 allowance for Extra Load tyres and tyres with nominal aspect ratio 40 suitable for speeds 300 km/h representing 7.2% of market. ETRTO views this as a challenging compromise package respecting political expectations and industry effort.

Proposal to amend document GRBP-83-32-Rev.1. Paragraph 1.2.9. amended to exclude special use Professional off-road tyres from scope. Paragraph 2.51. amended to read that the authority which has granted type approval may verify conformity control methods, with normal minimum frequency of verifications at least once every three years. Justification states special use tyres should be excluded as no limits will be established for them, and the three-year frequency aligns with Schedule 1 of the 1958 Agreement.

ETRTO comments on EC/JRC compromise proposal for Annex 4 tyre abrasion. ETRTO proposes an ALI range minimum of 0.5 as feasible and consistent with statistical distribution in MA results, rejecting the 0.7 range as unrealistic. For Generic Transfer Function gain, ETRTO recommends retaining a = 1.38 rather than the revised a = 1.45, to minimize rejection of good vehicle test results. ETRTO requests TFTA ToR amendment to confirm these conditions by February 2027 based on TA-45-9.

Proposal to amend document GRBP-83-32-Rev.1 to renumber Paragraph 6.1. as 6.1.1., renumber current Paragraph 6.1.1. as 6.1.2., introduce new paragraph 1.4. to Annex 3 Introduction, amend paragraph 2.8. with detailed abrasion index and level calculation equations, renumber items in Appendix 2, delete item 1.3. from Appendix 2, and amend item 1.3. in Appendix 6 to clarify transfer function applicability between circuit and drum test facilities.

Proposal to amend GRBP-83-32-Rev.1 to ensure robust tyre abrasion measurements regardless of test method used. Amendments modify paragraph 6.1 to require test facilities demonstrate equivalence per Annex 4 procedure; insert paragraphs 12.8 and 12.9 deeming inter-facility campaign participants equivalent for C₁ tyres and allowing pre-regulation test data through 1 July 2028; insert Annex 3 paragraph 1.4 requiring inter-facility equivalence assessment; amend Annex 3 paragraph 2.8 with abrasion calculation equations including transfer function coefficient; insert test report items 1.1–1.4 in Appendices 2 and 6; and insert new Annex 4 establishing equivalence demonstration procedure for vehicle and indoor drum test facilities.

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.

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.