33. The expert from EC introduced ECE/TRANS/WP.29/GRRF/2011/12 improving the current wet grip test method. The expert from ETRTO proposed GRRF-69-23 improving the wording of the EC proposal. Furthermore, the expert from ETRTO presented in GRRF-71-10 scientific data supporting ECE/TRAN/WP.29/GRRF/2011/12. The expert from Germany questioned the use of references to private standards, such as standards of the American Society for Testing and Materials (ASTM), which are not publicly available. The GRRF Chair offered to seek guidance from WP.29 on this horizontal issue. GRRF adopted ECE/TRANS/WP.29/GRRF/2011/12 as amended in Annex IV and agreed to send it to WP.29 and AC.1 for consideration at their March 2012 sessions, as part of draft Supplement 1 to the 02 series of amendments of Regulation No. 117, subject to a final review by GRRF at its February 2012 session (see also para. 35).

34. GRRF followed with interest the presentation (GRRF-71-06) made by the expert on behalf of ISO on a new test method for wet grip for buses and truck developed by ISO. Further information can be provided by Messrs. G. Dimitri (georges.dimitri@fr.michelin.com) or A. Dryden (dryden@iso.org).

35. The expert from ETRTO presented ECE/TRANS/WP.29/GRRF/2011/30, GRRF-71-04 and GRRF-71-12 introducing a new method for defining C3 snow tyres. GRRF adopted ECE/TRANS/WP.29/GRRF/2011/30 as amended by Annex IV, and agreed to send it to WP.29 and AC.1, for consideration at their March 2012 sessions, as part of draft Supplement 1 to the 02 series of amendments of Regulation No. 117 (see also para. 33), subject to a final review by GRRF at its February 2012 session, as well as the review of the proposal by the Working Party on Noise (GRB).

36. Due to lack of time, GRRF agreed to consider, at its next session, ECE/TRANS/WP.29/GRRF/2011/29 and GRRF-71-11 on an alternative to define C2 snow tyres. Following the adoption of ECE/TRANS/WP.29/GRRF/2011/30, GRRF agreed to remove from the agenda GRRF-71-09 combining ECE/TRANS/WP.29/GRRF/2011/29 and ECE/TRANS/WP.29/GRRF/2011/30.

37. GRRF agreed to consider GRRF-71-29 with an official symbol at its next session.

38. The secretariat was requested to inform GRB about the outcome of the GRRF discussion on Regulation No. 117.

12. The expert from the Russian Federation introduced ECE/TRANS/WP.29/GRB/2011/11, aimed at improving the test provisions for measuring the rolling resistance of tyres. The proposal received several comments (GRB-54-02, GRB-54-08 and GRB-54-10 amongst others). The Chair of GRB introduced GRB-54-12-Rev.1 proposing to amend ECE/TRANS/WP.29/GRB/2011/11. He clarified that the proposal did not affect the existing methods but result in a further option to the deceleration method. GRB adopted ECE/TRANS/WP.29/GRB/2011/11 as reproduced by Annex III to this report. However, some GRB experts suggested further technical assessment of the proposed alternative method to the next GRB sessions. The secretariat was requested to submit the proposal to WP.29 and AC.1, for consideration at their March 2012 sessions, as draft Supplement 1 to the 02 series of amendments to Regulation No. 117.

13. GRB noted also the work progress of the Working Party on Brakes and Running Gear (GRRF) on matters of common interest with GRB (ECE/TRANS/WP.29/GRRF/2011/12, ECE/TRANS/WP.29/GRRF/2011/29, ECE/TRANS/WP.29/GRRF/2011/30, GRRF-69-23, GRRF-71-29 and GRRF-71-31). Particularly, GRB endorsed ECE/TRANS/WP.29/GRRF/2011/30, inserting a new definition of C3 class tyres adopted by GRRF at its September session.