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.

JATMA submitted this position on the draft UN Regulation for tyre abrasion at GRBP-83-54. JATMA requests adoption of the indoor drum test method under conditions equivalent to the vehicle test method for type approval. JATMA proposes that the Generic transfer function coefficient should be 1.14, calculated excluding tyre code 127 which exhibits significant variation. JATMA also proposes that the abrasion index range for tyres used in the Annex 4 procedure should be set between 0.4 and 0.5, and that no restrictions should be imposed on baseline test facilities when applying the Specific Transfer Function.

This status report documents the Tyre Abrasion Task Force’s progress toward finalizing a draft UN Regulation on tyre abrasion for C1 tyres, as presented to GRBP 83 Part II. The task force pursued three workstreams: data analysis to reduce method uncertainty and inversion risk, editorial improvements to increase clarity of the draft regulation, and development of a method equivalence solution. GRBP 83 Part I achieved consensus on limit values and introductory dates but could not reach consensus on equivalence procedures between convoy and drum methods. Six informal documents (GRBP-83-32-Rev.1, GRBP-83-48-Rev.1, GRBP-83-49, GRBP-83-50-Rev.1, GRBP-83-53, and GRBP-83-55) addressing equivalence methodology, drum specifications, and code of practice frequency were submitted for potential adoption at the extraordinary GRBP 83 Part II session.

Proposal to delete Table of contents, Annex 10 and all its appendices, amend para. 1.1. to clarify application to new pneumatic tyres of classes C1, C2 and C3 in new state regarding sound emissions and rolling resistance and in new and worn state regarding wet adhesion, delete para. 1.3., amend para. 2.18. to specify reference tyres F2872-25, F2871-25, F3678-25 and F3677-23, delete para. 2.21., delete para. 3.1.1.1., amend para. 3.2.1. to describe major features and their effects on tyre performance, delete paras. 5.7. to 5.10., delete Annex 1 items 8.6. and 8.6.1., amend Annex 5 part (b) para. 1.1.1. to establish surface friction values by trailer or vehicle method according to tyre class and SRTT, amend Annex 5 part (b) para. 1.1.1.1. regarding coefficient of variation and peak braking force coefficient, and delete Annex 10. Document based on GRBP/2025/28, GRBP-82-27, GRBP/2026/6, GRBP-83-20/Rev.2 and GRBP-83-48/Rev.1.

Proposal to amend UN R141 under section 2 to add definitions of Automated Driving System, Dynamic Driving Task, Category X vehicles, Category Y vehicles, Logical signal, and Vehicle Master Control Switch, amend under section 5 to update performance requirements and warning signal specifications for vehicles equipped with an ADS and towed vehicles, amend Annex 1 to add a vehicle ADS status field, amend Annex 3 regarding test procedures for TPMS including deactivation of TPRS and CTIS, amend Annex 4 regarding test weight and refill functionality checks, amend Annexes 5A and 6 regarding towed vehicle communication interfaces, and insert new Annex 9 containing special testing provisions for vehicles equipped with an ADS.

Proposal to amend paragraph 1, footnote 1, insert new paragraphs 2.23. to 2.26. defining Automated Driving System, Dynamic Driving Task, Category X vehicles, and Category Y vehicles, amend paragraph 4.4.1., footnote 2, amend section 5.2.3. to add requirements for vehicles equipped with an ADS and exclude speed warning label requirements for vehicles of categories X and Y, amend Annex 1, footnote 4, insert new item 6.2. regarding ADS equipment, insert new paragraph 2.2. in Annex 2 Section I regarding ADS equipment, and insert new paragraph 4.2. in the Addendum to communication form regarding brief description of the ADS if fitted.

The proposal adds Annex 5 on special provisions for testing vehicles equipped with an Automated Driving System (ADS) and adds definitions for ADS, Dynamic Driving Task, Category X and Y vehicles, logical signal, and Vehicle Master Control Switch. Amendments modify run-flat warning system requirements, braking performance tests, and tyre detection procedures to accommodate ADS-equipped vehicles.

Proposal to amend paragraph 1 (Scope) to clarify that the Regulation applies to new pneumatic tyres designed primarily for vehicles of category L₁, and to specify that approvals shall not be granted to tyre types designed exclusively for off-road use marked “NHS”, for competitions, or for bicycle rims according to ISO 5775-2:2021.

Proposal to amend paragraph 1.1. to specify that UN R106 applies to new pneumatic tyres designed primarily for agricultural and forestry vehicles in categories T, R and S; amend paragraph 1.1. footnotes to include definitions; and amend paragraph 3.1.5.3. to address marking requirements for implement tyres for mixed applications of speed category symbol D or E where service descriptions for trailer and traction applications are equal.

Proposal to revise the definition of principal grooves in paragraph 2.14.1.; delete paragraph 2.48. and renumber subsequent paragraphs; amend paragraph 2.51. regarding material supplier definition; revise paragraph 3.2.6. on M+S inscription requirements; modify paragraph 4.1.5.3.2. to include a table of tyres classified for severe snow conditions; delete paragraphs 4.1.5.3.2.1., 4.1.5.3.2.2., and 4.1.5.3.2.3.; revise paragraphs 6.5.3., 6.5.8., 6.6., 6.7.4., and 7.1.5. regarding material supplier requirements and diameter calculations.

Proposal to modify paragraph 2.4. to define “Material supplier,” delete paragraph 2.59., and renumber paragraphs 2.60., 2.61. and 2.61.1. as 2.59., 2.60. and 2.60.1., amend paragraphs 3.2.8., 3.6., and 4.1.5.3.2. regarding M+S markings and tyre classifications, and delete paragraphs 4.1.5.3.2.1., 4.1.5.3.2.2. and 4.1.5.3.2.

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

Proposal to amend UN Regulation No. 172 based on GRBP/2026/10 as amended by GRBP-83-15-Rev.1. Amendments include revised definition of supplier of tread in paragraph 2.2.; modification of paragraph 6.2. to require tyres to meet conditions in paragraph 6.2.1. or 6.2.2.; insertion of new paragraphs 6.2.2., 6.2.2.1., 6.2.2.2., and 6.2.2.3. establishing calculation methods for deformation potential and number of traction elements based on tyre class and nominal rim diameter; insertion of new paragraph 6.4.(a) for class C₁ tyres; renumbering of former paragraphs 6.

Proposal to amend paragraph 2.2. to clarify the definition of “Supplier of the tread used for retreading process”; insert new subparagraph (a) in paragraph 6.4. establishing requirements for class C1 tyres; renumber former subparagraphs (a) and (b) as (b) and ©; replace “Appendix 1” with “Schedule 1” in paragraph 8.; amend paragraph 12.1. concerning type approvals as from 1 September 2030; amend paragraph 12.3. regarding acceptance of existing type approvals of class C3 tyres; and amend Annex 1 regarding communication of type approval for retreaded tyres.