Wet grip ratings

One of the most important elements shown on each tyre’s label is the wet grip rating, something for which all new tyres are tested. Wet grip ratings are explained below.

What is wet grip?

Wet Grip Ratings

Wet braking performance is a critical safety feature and relates to how quickly you will be able to stop in wet conditions.

Tyres play a crucial role in a vehicle’s stopping distance and those with excellent wet grip have shorter braking distances on slippery roads, which is essential for keeping you safe in the rain.

The difference between each grade means an increase or decrease in stopping distance between one or two car lengths (3-6 metres) when braking at 50mph.

The difference between categories A and F is more than 18 metres (testing according to regulation EC1222.2009) in stopping distance. An A-rated tyre provides the shortest braking distances on wet roads, and thus the best grip, whereas an F rated tyre will have the longest braking distance in the wet, ie the worst level of grip.

Categories D and G are not used.

It is important to remember that a tyre with a good rating for wet grip can be trusted for better braking in dry conditions, too. A good rating for wet grip therefore brings with it important safety benefits whatever the conditions. etyres recommends placing utmost importance on a tyre’s wet grip rating.

How is it calculated?

According to the tyre labelling legislation wet grip can be tested in one of two ways. The first is the wet braking vehicle test, which measures wet braking performance on a wet road surface, braking from 50mph to 12mph.

The second test is a skid trailer test, which measures friction between the road and a tyre, conducted at 40mph. The end result of both tests provides a Wet Grip Index (WGI), which describes the improvement in percentage in relation to the reference tyre.

To find out more about tyre labelling and for help choosing the right tyres for you, call our National Sales Team on 0800 028 9000. To order new tyres online simply enter your tyre size into the search tool above.