Proposal to elaborate on the concept of tyre deceleration (dω/dt) in the test procedures. The Russian Federation has developed a “Deceleration Calculator” for use in the UN R117 procedures. Following work by an ad hoc group (including NAMI, UTAC, and ETRTO) formed to review and validate this tool, Russia has prepared this new proposal, modifying the version (document GRB/2013/10) submitted at the last GRB session. The changes primarily concern the explanation of the tool rather than the basic mathematical equations.

24. Recalling the purpose of ECE/TRANS/WP.29/2013/66, the Chair of GRRF stressed that WP.29 was expecting GRRF to conclude its deliberation about the wet grip limit values. The GRRF experts introduced their positions (GRRF-76-05, GRRF-76-07, GRRF-76-08, GRRF-76-11, GRRF-76-12, GRRF-76-26, GRRF-76-27, GRRF-76-28). The expert from the EC reported on the concerns expressed by the Directorate-General for Mobility and Transport of the European Commission (DG Move). GRRF confirmed the limit values proposed in para. 6.2.2. for Tyres of C2 category and agreed to amend the proposed limit values in para. 6.2.3. for Tyres of C3 category in ECE/TRANS/WP.29/2013/66. GRRF requested the secretariat to submit this amendment as reproduced in WP.29-162-05 to WP.29 and AC.1 for consideration at their March 2014 session.

24bis. The expert from the Russian Federation presented GRB-59-02 proposing a tyre rolling resistance test results evaluation using a mathematical algorithm, to be added as an alternative to the existing one in the text of the Regulation. He also presented the results of a validation study of the proposed algorithm for tyres of the C1 category performed in France, in cooperation with the Russian Federation (GRB-59-07 and GRB-59-08). GRRF noted that this proposal may be submitted by GRB to WP.29 as a supplement to UN Regulation No. 117. GRRF recommended further steps for a better understanding of the proposed method’s sensitivity, suggesting: (i) extending the validation study for tyres of categories C2 and C3 and (ii) verifying the application of the proposed alternative in the conditions of the conformity of production. The GRRF Chair invited the experts to provide their comments on the proposal to the GRB secretariat with a copy to the expert from the Russian Federation.

Text as adopted by the Working Party on Brakes and Running Gear (GRRF) at its 75th session based upon a proposal by the European Commission, France and ETRTO to introduce wet grip provisions and testing procedures for tyres of categories C2 and C3.

[The World Forum agreed to keep this proposal on the agenda for consideration at its November 2013 session pending reconfirmation of the proposed limit values by GRRF at its September 2013 session.]

26. The expert from ETRTO presented GRRF-75-02, justifying the wet grip limit values for C3 tyres specified in ECE/TRANS/WP.29/2013/66. Following a tour de table, the Chair noted that half the experts were in favour of amending the proposed limits for normal and traction tyres whilst retaining the proposed limits for snow and special use tyres, while the other half were in favour of maintaining those proposed in ECE/TRANS/WP.29/2013/66. The GRRF Vice-Chair volunteered to lead a discussion with interested experts on a proposal for GRRF at its next session. GRRF preferred to postpone the vote by WP.29 and AC.1 on ECE/TRANS/WP.29/2013/66 until their June 2014 sessions.

32. The Chair of GRRF reported that GRRF was still seeking a consensus proposal on new wet grip limits for tyres of category C3 in ECE/TRANS/WP.29/2013/66 (Supplement 5 to the 02 series of amendments to UN Regulation No. 117) and proposed WP.29 and AC.1 to defer the vote.

24. Recalling the purpose of ECE/TRANS/WP.29/2013/66, the Chair of GRRF stressed that WP.29 was expecting GRRF to conclude its deliberation about the wet grip limit values. The GRRF experts introduced their positions (GRRF-76-05, GRRF-76-07, GRRF-76-08, GRRF-76-11, GRRF-76-12, GRRF-76-26, GRRF-76-27, GRRF-76-28). The expert from the EC reported on the concerns expressed by the Directorate-General for Mobility and Transport of the European Commission (DG Move). GRRF confirmed the limit values proposed in para. 6.2.2. for Tyres of C2 category and agreed to amend the proposed limit values in para. 6.2.3. for Tyres of C3 category in ECE/TRANS/WP.29/2013/66. GRRF requested the secretariat to submit this amendment as reproduced in WP.29-162-05 to WP.29 and AC.1 for consideration at their March 2014 session.

24bis. The expert from the Russian Federation presented GRB-59-02 proposing a tyre rolling resistance test results evaluation using a mathematical algorithm, to be added as an alternative to the existing one in the text of the Regulation. He also presented the results of a validation study of the proposed algorithm for tyres of the C1 category performed in France, in cooperation with the Russian Federation (GRB-59-07 and GRB-59-08). GRRF noted that this proposal may be submitted by GRB to WP.29 as a supplement to UN Regulation No. 117. GRRF recommended further steps for a better understanding of the proposed method’s sensitivity, suggesting: (i) extending the validation study for tyres of categories C2 and C3 and (ii) verifying the application of the proposed alternative in the conditions of the conformity of production. The GRRF Chair invited the experts to provide their comments on the proposal to the GRB secretariat with a copy to the expert from the Russian Federation.

55. The World Forum considered the pending proposal for amendments to Regulation No. 117 listed under agenda item 4.12.3 (document ECE/TRANS/WP.29/2013/66) and recommended its submission to AC.1 for voting, subject to the correction of para. 47 below (see WP.29-162-05).

56. Page 1, the title, replace “Supplement 5” by “Supplement 6”. Page 2, paragraph 6.2.3, correct the wet grip index G for normal tyres other than traction tyres to read 0.80.

[The proposal was adopted as amended as “Supplement 6 to the 02 series of amendments to UN Regulation No. 117” by a vote of 36 in favor and none either opposed or abstaining.]