This paper deals with the legal demands and its consequences of both regulations (UN/ECE) No. R 117 and (EU) No. 1235/2011, with regards to the tyre wet grip performance for Passenger Car tyres C1, Light Commercial Vehicle tyres C2 and Truck and Bus tyres C3.

The current Brussels EU Regulation No. 1235/2011, valid from May 30, 2012, has introduced a European Tyre Label with wet grip index G classes from A to G for Passenger Car tyres C1, Light Commercial Vehicles tyres C2 and Truck/Bus tyres C3. Every wet grip class for each vehicle category has a defined band of numerical values for the wet grip index G. The legislated wet grip values G in this Regulation are very low. The measured braking distances and corresponding impact speeds of the test vehicles, by using tyres with wet grip indices G according to the proposed amendments of UN/ECE R 117 on vehicles of all classes, are showing very critical results.

Regulation No. 1235/2011 of the European Parliament and the Council for Type Approval of Vehicles (EU) as well as Regulation No. 117.02 of the Economic Commission of the United Nations for Europe (UN/ECE) should be changed in such a way, that for C1-tyres (normal passenger cars tyres) the minimum wet grip index G is 1.25. All C2-tyres (light commercial vehicles tyres) should at least meet a minimum wet grip index of G = 1.1. All C3-tyres (heavy trucks and busses tyres) should at least meet a minimum wet grip index of G = 0.95.

Document “ECE/TRANS/WP.29/GRRF/2013/9, Proposal for Amendments to Regulation No. 117”, dated 7th of December 2012, as discussed in the 74th session of GRRF, 19th-21st of February 2013, should be changed according to the above requested and listed minimum wet grip values G for C1-, C2- and C3-tyres. Wet grip classes D, E, F and G could therefore be eliminated.

Due to the missing lower limits for G in the wet grip class F for C1, C2 and C3 tyres according to Commission Regulation (EU) No. 1235/2011, officially valid from 30 May 2012, a tyre-to-road coefficient of adhesion in the extreme of 0 (zero) is legally permitted. This is an apparent flaw in above cited EU regulation, which causes a potential danger to the road traffic safety for all motor vehicles in Europe with such tyres. The wet grip class F has to be removed urgently from said EU regulation, since a direct liability of the responsible EU Commission can not be excluded.