Proposal to expand and improve the current definition of a radial structure while ensuring the radial tyres key features (mechanical decoupling between the tread and the bead).
13. Based on a study (GRBP-76-04), the expert from ETRTO proposed a new definition for “radial tyre” (ECE/TRANS/WP.29/GRBP/2022/21). The proposal also addressed other issues, such as the definition of snow tyres, requirements for special use tyres of class C1, addition of an optional prefix for extra load tyres, a clarification on the description of the load/speed test for run flat/extended mobility tyres and editorial corrections.
14. GRBP adopted ECE/TRANS/WP.29/GRBP/2022/21 and requested the secretariat to submit it for consideration and vote at the March 2023 sessions of WP.29 and AC.1 as draft Supplement 25 to the 02 series of amendments to UN Regulation No. 30.
16. The expert from ETRTO reported on their ongoing assessment (GRBP-75-22) of the new definition of “radial tyre” that had been proposed by the experts from France and EC at the previous session (ECE/TRANS/WP.29/GRBP/2021/9). GRBP looked forward to the outcome of the ETRTO activities and expected that a final proposal would be submitted to the next session. The experts from the Netherlands and Russian Federation pointed out that the radial tyre definition may not necessarily cover new types of tyre structures and that adding a new subgroup of tyres with their own definition should be considered as an alternative.
15. The experts from France and EC introduced an updated proposal for the new definition of “radial tyre” (ECE/TRANS/WP.29/GRBP/2021/9). The same definition was also proposed for UN Regulations Nos. 54, 75, 106, 108 and 109 ECE/TRANS/WP.29/GRBP/2021/10. The experts from Canada and the United States of America raised a number of questions on the proposal (GRBP-74-07) and pointed out that they had started consultations with the authors. GRBP invited the stakeholders, in liaison with ETRTO, to continue discussions and agreed to come back to the proposal at the next session.
11. The expert from France proposed a new definition of “radial tyre” (ECE/TRANS/WP.29/GRBP/2020/21 and GRBP-72-22), which was amended by the expert from EC (GRBP-72-24). The expert from Japan held the view that the proposal was not sufficiently clear. The expert of ETRTO pointed out that his organization would need technical justification to support the proposal. The Chair invited all experts concerned to internally re-discuss the proposal and to submit an updated document to the next session.