Proposal to introduce a procedure and thresholds on wet grip performance for C1 tyres in worn state.

Proposal to introduce provisions for ice grip tyres, clarify provisions on Conformity of Production, sample submissions, and testing methods, and to make editorial corrections and improvements.

Text prepared by the Informal Working Group on Measurement Uncertainties (IWG MU) as a document of reference. IWG MU was given the first task to amend UN Regulations Nos. 51 and No.117 to reduce measurement uncertainties

Worn Wet grip Index equation proposed by ETRTO on 25 October
Questions addressed by WTPP and further assessment
Responses provided by ETRTO provided to WTPP on 8 November
WTPP conclusion

IWG WGWT proposes to amend document ECE/TRANS/WP.29/GRBP/2021/12

IWG to propose amendments to UN R117

1. In paragraph 5.3.1.2. the wording has been adjusted to the definitions as amended with GRBP/2021/12 proposal to identify adhesion on wet surfaces of tyre in new state.
2. Paragraph renumbered and reworded in line with the text proposed in paragraph 8.3.1. of document ECE/TRANS/WP.29/2021/17.
3. Paragraph 12.2. has been reworded according to the intentions of paragraph 41. of the General Guidelines for United Nations regulatory procedures and transitional provisions in UN Regulations to avoid TAA’s to interpret a mere change in markings as a change introduced by the new SoA.
4. Paragraph 12.6.1. is in line with paragraph V.9bis. of the General Guidelines for United Nations regulatory procedures and transitional provisions in UN Regulations. Proposed paragraph 12.4.1., is introducing date limitations and precise reference to a specific series of amendments and in such does not conform to V.9 bis transitional provisions. Consequently, it should then be deleted from the proposal.
5. In Annex 1, paragraphs 8.2. and 8.3., the reference to non-existent items was removed.
6. In Annex 2 – Appendix 1, Example 1, the wording has been aligned to the other examples provided in Annex 2.
7. In Annex 9, paragraphs 2.1.5 to 2.2.1.2.4.1. have been reworded to clarify the preparation of class C1 tyres in worn state.
8. In Annex 9 – Appendix 1, the example of worn tyre preparation report example has been updated to remove unnecessary and ambiguous data to be reported.
9. In Annex 9, Appendix 2, Example 2, the report example has been updated in line with the proposal of Annex 5, Appendix, Example 2 of document ECE/TRANS/WP.29/GRBP/2021/17.

Proposal to maintain the performance stages for the following reasons:

• By removing the performance stages, we would allow two different markings, with and without performance stage indication, for the same actual performance level depending on whether the type approval was granted according the 02 or 03 series of amendments.
• Some countries which are not contracting parties of 1958 Agreement refer to stage 1 and stage 2 of 02 series of amendments of UN Regulation No. 117. Therefore, the removal of the stages would create some ambiguity and misunderstanding of the actual performance of the product.
• The above is even more important for tyre of classes C2 and C3 as they are not affected by the introduction of the performance for the adhesion on wet surfaces for tyres in worn state, and for which the suffix B is not added to the approval marking.

This revised document intended to present to amend 117 the timetable for the work related to Regulation No. 117 has been shifted with approximately 12 months for this part.
The aim of the IWG is to propose harmonized measures for evaluating systematic errors and random errors to improve the test procedures to reduce measurement uncertainties

Proposal to add requirement on the monitoring of the machine deviation for rolling resistance measurement.

Flyer in German and French for a September 2017 technical conference: Lärmarme Strassenbeläge aus Asphalt/Revêtements bitumineux peu bruyants.

Proposal to introduce provisions for ice grip tyres, clarify Conformity of Production, sample submissions, and testing methods, and to make editorial corrections and improvements.

Proposal to introduce a procedure and thresholds on wet grip performance for tyres in worn state for C1 tyres as submitted to GRBP by the Worn Tyres working group.

Proposal from the Worn Tyres working group to introduce a procedure and thresholds on wet grip performance for C1 tyres in worn state.

Presentation on wet grip test issue concerning to use of SRTT_worn for RRT.

Proposal to replace “markings” by “approval mark” in paragraph 4.4.1. to clearly specify the intended application of the provision (i.e., to the approval mark, not to all markings).

Proposal to include requirements for wet grip of tyres of classes C2 and C3 in worn state to the scope of the working group activities.

Overview of UTAC CERAM testing designed to consider the impact of additional tightening of tyre performance limits on the balance
between legal requirements (rolling resistance, wet grip and rolling sound emission) and other performance aspects not subject to legal requirements.

Proposal to expand the scope of the activity to include C2 and C3 tyres.