Proposal to improve accuracy in the calculation of tire rolling resistance by the deceleration method.

Proposal from the Russian Federation to elaborate on the concept of tyre deceleration (dω/dt) in the test technology. The proposal is based on informal document GRB-56-02 from the previous GRB session.

Corrections to the proposal from the Russian Federation to elaborate on the concept of tyre deceleration (dω/dt) in the test technology.

Text prepared by the Russian Federation to elaborate on the concept of tyre deceleration (dω/dt) in the test technology.

Further background as requested at the last GRB meeting on the recommended use of a “deceleration calculator” software for the deceleration test method in the test procedure for measuring rolling resistance.

Proposal to revise the European Tyre and Rim Technical Organisation (ETRTO) proposals (documents GRB-58-02 and GRRF/2013/30) to correct inconsistencies in time measurement accuracy in annex 6 of the regulation.

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.

Regulation 117, Annex 6 specifies several time duration values while Annex 6, Appendix 1 gives only one control accuracy value for time in its paragraph 4 (d): plus or minus 0.02 second. This means that this accuracy value applies to all the time durations specified in Regulation 117, Annex 6 and quoted above. This is not realistic for durations of more than one minute and not well fitted to the need of data acquisition for deceleration method. Therefore, Russia and ETRTO propose to introduce two accuracy sets of values in paragraphs 4 and 5 of Regulation 117, Annex 6, Appendix 1:

1. a control accuracy of +/- 0.2 % s and a corresponding instrumentation accuracy of +/- 0.1 % s for the time increments specified in Annex 6 paragraph 3.5.a for the data acquisition in the deceleration method, both in ∆ω/∆t or dω/dt form, and
2. a control accuracy of +/- 5% and an instrumentation accuracy of maximum +/-10 sec for the other time durations specified in Annex 6.

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.

Proposal to introduce a “Deceleration Calculator” (dω/dt) for use in the UN R117 test procedures. This procedure was developed by Russia and validated by an ad hoc group (including NAMI, UTAC, and ETRTO).

At the 58th GRB session, the expert from ETRTO introduced GRB-58-02, proposing new time measurement accuracy for instrumentation involved in the rolling resistance method (Annex 6 of the UN Regulation). The expert from the Russian Federation introduced GRB-58-13, arguing that this change of accuracy was not needed for Annex 6. This present revised proposal has been prepared the ETRTO and approved by Russia.

Proposal for an alternative to the proposal (document GRRF/2015/9) to restore transitional provisions incorrectly deleted by Supplement 6 to the 02 series of amendments.

This proposal is an alternative to that represented in document GRRF/2015/9 and GRRF-79-19.

Proposal to prepare an amendment to UN Global Technical Regulation (GTR) No. 16 on tyres in order to introduce provisions concerning wet grip performance, rolling resistance, and qualification of tyres for use under severe snow conditions in accordance with the same provisions introduced recently into UN Regulation No. 117.

Proposal to align UN R117 related to approval numbers and markings in line with the provisions of Schedule 4 to the 1958 Agreement addressing the concern raised by the Informal Working Group on the
International Whole Vehicle Type Approval (IWVTA).

Proposal to align the provisions of UN R117 regarding approval numbers and markings with the provisions of Schedule 4 to the revised 1958 Agreement.

UN R117 establishes test procedures ensuring reliability, repeatability and reproducibility of results through standard reference test tyres manufactured by Manufacture Francaise des Pneumatiques Michelin in accordance with ASTM International standards. In 2024, the Russian Federation’s technical service was officially refused supply of these tyres due to export sanctions. The Russian Federation contends this refusal constitutes discrimination against a Contracting Party to the 1958 Geneva Agreement and calls on WP.29 to assess this discrimination and explain to the manufacturer its role in implementing the Agreement within the UN system.