# Regulation (EC) No 1222/2009 of the European Parliament and of the Council of 25 November 2009 on the labelling of tyres with respect to fuel efficiency and other essential parameters (Text with EEA relevance), Division 4: TESTING METHODS FOR MEASURING WET GRIP

Extent: E+W+S+N.I.

For the calculation of the wet grip index (G) of a candidate tyre, the wet grip braking performance of the candidate tyre is compared to the wet grip braking performance of the reference tyre on a vehicle travelling straight ahead on a wet, paved surface. It is measured with one of the following methods:
vehicle method consisting of testing a set of tyres mounted on an instrumented passenger car,
testing method using a trailer towed by a vehicle or a tyre test vehicle, equipped with the test tyre(s).

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Source: https://www.legislation.gov.uk/eur/2009/1222/annex/V/division/4 (the official version)
Page: https://openlegislation.uk/eu-regulation-2009-1222/annex-V/division-4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.