Amendment of UN/ECE Regulation No. 117

SAFE TYRES UP TO THE WEAR LIMIT

The United Nations Economic Commission for Europe (UNECE) has revised UN ECE-R117 in order to increase the sustainability of tyres and ensure their safety until they are worn out. Previously, requirements for rolling resistance, compliance with limit values for rolling noise or handling characteristics in snow and rain applied to new tyres. With the amendment to UN ECE-R117, manufacturers must now also meet these tyre performance requirements for worn tyres.

The modification to UN/ECE Regulation No. 117 of the United Nations Economic Commission for Europe (UN/ECE-R117) with the amendment series 03 and 04 began in the meeting of the UNECE Working Group GRBP in January 2019. At that meeting, the experts from France discussed the introduction of limits with regard to the wet properties of worn tyres. The aim of those limits is to increase the lifespan and safety of tyres up to almost the legally defined minimum tread depth. For testing, the tyres are machined to a fixed contour and remaining tread depth. The tyre processed in this way is tested for its wet grip performance in comparison to a standard reference tyre with reduced tread depth, which has also been newly introduced. Depending on the type of use of the tyre type, the tyre must comply with certain minimum requirements compared to the reference tyre.

This amendment phases in minimum end-of-life requirements for vehicle tyre products for the first time. These requirements only take tyre tread depth into account and ignore other properties, such as ageing of the rubber compound or deterioration in structural strength. However, this singular approach gives rise to a host of requirements for the machining process used on the test specimen and for the tyre testing in practice.