GRBP/2025/15
UN R108: Proposal for a Supplement to the 01 series of amendments

Proposal to:

  1. Correct the description of a tyre to exclude aspects outside the scope of UN R108
  2. Align the snow tyre definition to UN R109 and 172
  3. Clarify the definition of nominal rim diameter
  4. Clarify the definition of principal grooves by eliminating the circular reference between this definition and the position of tread wear indicators
  5. Introduce a definition for tread depth (used in the requirements for special use and professional off-road tyres)
  6. Amend para. 4.1.5.3.2. to remove the retreaded reference to traction tyre classification because it is not applicable to tyre of class C1
  7. Clarify the calculation of the tyre section width
  8. Replace “XXX” with the UN Regulation No. 172 in the references to the approval of retreaded tyres with regard to their snow performance and/or classification as traction tyre.
UNECE server
Excerpts from session reports
GRBP | Session 81 | 18-21 Feb 2025

15. The expert from ETRTO submitted editorial corrections and clarifications to the new 01 series of amendments to UN Regulations Nos. 108 and 109 (ECE/TRANS/WP.29/GRBP/2025/15 and ECE/TRANS/WP.29/GRBP/2025/16). GRBP adopted these proposals, as amended GRBP-81-11-Rev.1 and GRBP-81-12-Rev.1., and requested the secretariat to submit them for consideration and vote at the June 2025 sessions of WP.29 and AC.1 as respectively draft Supplement 1 to the 01 series of amendments to UN Regulation No. 108 and draft Supplement 1 to the 01 series of amendments to UN Regulation No. 109. For draft Supplement 1 to the 01 series of amendments to UN Regulation No. 108, GRBP recalled that the pending correction in ECE/TRANS/WP.29/GRBP/2024/24 should be added.