What are Winter Tyres?
In many countries there is a duty to use Winter Tyres at certain times or road condition which could be ice, snow mud or smoothness.
Winter Tyres are supposed to be used with wintery road conditions and low temperatures. They have a rubber compound which is enough elastic with low temperature to achieve a sufficient gearing and transmission with the underground.
Winter Tyres are always marked with the M+S Symbol (Mud and Snow). The EU regulation nr.661/2009 dated from the 13th July 2009 declares M+S marked tyres as tyres which above all have a tread profile, tread compound and constitution in order to achieve better driving and traction qualities on snow.
Another symbol for Winter Tyres contains a mountain and a snowflake (Alpine Symbol) and is always awarded from the American Road Service NHTSA.
Unlike summer tyres, winter tyres in addition to their normal profile have slats which make it possible to get a gearing on loose underground like snow.
When the temperature drops below 7°C the rubber compound of a summer tyre begins to harden. In contrary to that the rubber compound of a winter tyre contains a higher percentage of natural rubber so it is able to retain its elasticity.
A lot of different test have shown that even when travelling at the low speed, a winter tyre can stop up to 11 meters shorter on icy roads than a normal tyre at wintry weather condition below 7°C.