Proposal to amend paragraph 2.18. to update Standard Reference Test Tyre definitions to ASTM International standards: E1136-19 for SRTT14, F2493-24 for SRTT16, F2872-25 for SRTT16C, F2871-25 for SRTT19.5, F2870-23 for SRTT22.5, F3678-25 for SRTT19.5 siped, and F3677-23 for SRTT22.5 siped. Also amend paragraph 12.21. to accept existing type approvals and grant extensions to class C₃ tyres using either SRTT19.5 or SRTT22.5 before 1 September 2028, and use SRTT19.5 siped or SRTT22.

ETRTO measurement uncertainties reduction efforts for UN R117 rolling sound emission test methods are progressing through outdoor and indoor Round Robin tests. Eight of thirteen outdoor test centres have completed tests for C₁ and C₂ tyres; remaining centres anticipate completion by mid-year. Indoors, two of six ETRTO test centres completed tests with others expected finished by mid-year. An intermediate report with available data will be presented in September 2026, full results postponed to February 2027, and the Working Document with test method evolution now expected in September 2027 instead of February 2027.

Proposal to supersede GRBP/2025/28, consolidating amendment proposals from GRBP/2025/28, GRBP-82-27, GRBP/2026/6, and GRBP-83-20-Rev.2. Changes include moving tyre abrasion provisions to a separate UN Regulation, deleting paragraphs 5.7 to 5.10 and Annex 10, updating ASTM standard references to F2872-25, F2871-25, and F3678-25, amending Annex 5 part (b) paragraph 1.1.1., and deleting paragraph 2.21. defining abrasion performance terms.

Proposal to amend Annex 5, part (B) of UN R117. Changes include replacing “Average Deceleration (AD)” with “braking force coefficient (BFC)” terminology throughout paragraphs 2.2.2.1., 2.2.2.7.1., 2.2.2.7.2., and 2.2.2.7.3. Paragraph 2.2.2.3. is amended to clarify terminology regarding vertical static test load and load capacity. Paragraph 2.2.2.7.4. is deleted. Paragraphs 2.2.2.7.5. through 2.2.2.8.4. are renumbered and amended to align the wet grip test method for C2 and C3 tyres with changes made to the passenger car test method and ISO 15222:2025.

Proposal to amend para. 2.18. to update the year reference in standard F2493 from 24 to 26, amend paras. 6.6. and 6.7. to change “classified” to “categorized”, revise tread depth and void to fill ratio requirements for class C1 special use tyres, restructure requirements for professional off-road tyres with subsections for each class, amend Annex 3 para. 4.2.2. to correct the measurement unit of coefficient K1 to dB(A), amend Annex 3 Appendix 1 Part 2 item 3.1. to update the ISO 10844 year reference from 2014 to 2021, and amend Annex 7 Appendix 3 Item 5 to enable SRTT weighted average to be reported for each candidate in the test results table.

Proposal to amend para. 2.18. to change the reference year from 24 to 26 for standard F2493, add new para. 2.21. defining “road legal race tyre,” add new para. 4.2.8. requiring the inscription “RLR” for road legal race tyres, insert new footnote 12 on marking height, renumber current footnote 12 to footnote 13 and amend its text, amend para. 5.4.1. to reference footnote 13, add new para. 6.9. establishing requirements for road legal race tyre classification, add new item 4.3. to Annex 1, amend para. 6.7. to change “classified” to “categorized,” amend Annex 3 para. 4.2.2. tables to change K1 unit from C to dB(A), amend Annex 3 Appendix 1 Part 2 item 3.1. to update ISO10844 reference from 2014 to 2021, and amend Annex 7 Appendix 3 Item 5 table to enable reporting of SRTT weighted average for each candidate.