13. The expert from ETRTO introduced draft amendments to clarify several definitions and to make editorial changes (ECE/TRANS/WP.29/GRBP/2025/10). GRBP adopted these proposals, as amended by GRBP-81-06-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 draft Supplement 28 to UN Regulation No. 54.

71. The Chair of GRBP presented draft amendments under agenda item 4.8.1. The World Forum recommended their submission to AC.1 for voting.

72. WP.29 considered draft amendments under agenda items 4.8.2 to 4.8.13 and recommended their submission to AC.1 for voting, subject to the following editorial corrections: ECE/TRANS/WP.29/2025/68, ECE/TRANS/WP.29/2025/71, ECE/TRANS/WP.29/2025/72, paragraph 6.1.1.1., amend to read: “6.1.1.1. The section width S of a tyre fitted on the measuring rim shall be calculated by the following formula: , and rounded to the nearest millimetre, Where: S1 is the nominal section width in millimetres, as shown on the sidewall of the tyre in the tyre designation as prescribed; …” ECE/TRANS/WP.29/2025/72, Annex 5, Table 7, first column, rows MU90-15, MV90-15, MU85-16, MV85-15, delete “M/C”. ECE/TRANS/WP.29/2025/73, paragraph 2.22.1., the first sentence, amend to read: “When the nominal rim diameter (“d” symbol) is expressed by code, the values of the “d” symbol are as follows:…”. ECE/TRANS/WP.29/2025/76, paragraph 6.8., first sentence, delete “all of”. ECE/TRANS/WP.29/2025/77, paragraph 5.2.3.2.2., replace “… the Snow Grip Symbol for Studded Tyres1 as described in UN Regulation No.” with “… the Snow Grip Symbol for Studded Tyres1 as described in UN Regulation No. 164)”. Paragraph 5.2.5.2., first line, delete “a”. ECE/TRANS/WP.29/2025/78, paragraph 12.3, replace “… based on snow performance test described in Annex 7 to this Regulation…” with “… based on snow performance test described in Annex 7 to UN Regulation No. 117…”.