Winter tyres have been specially developed for lower temperatures and roads in winter conditions. They possess a higher percentage of natural rubber than summer tyres do, as they need to maintain grip and flexibility even in cold conditions. A marked improvement in driving and traction performance is noticeable thanks to their special tread profile and tread compound. The composition structure of tyres varies according to each region. In the UAE, winter tyres are not used for obvious weather reasons. In general, winter tyres are designed for temperatures which go from -15°C to +15 °C (Celsius). Reliable winter tyres must possess, above all, a good rubber adhesion and sufficient edge grip to allow travelling on wintry ground. Winter tyres are marked with a M&S Symbol (Mud and Snow), according EWG (Environmental Working Group).
There are different tread profile depth minimums, which are recommended for winter and summer tyres. Winter tyres ought to have a tread profile depth of 4 mm, although the minimum recommended by law is 1,6mm. For safety reasons, one should not wait until the tyres have become worn down to this level, since, otherwise, a sound contact with the ground can no longer be guaranteed. It is recommended to swap winter tyres after 6 years at the latest, otherwise the rubber mix becomes too hard, and that can cause the grip to become unreliable in very low temperatures.
Each type of winter tyre is designed for a specific maximum speed. On the tyre sidewall there is an embossed code with numbers and letters that provides information about the speed index. In the case that tyres should be fitted to a faster vehicle, there must be a sticker on, to indicate the lowest maximum speed to the driver.