Unlike summer tyres, winter tyres are designed to perform best when the temperature drops below 7oC. Winter tyres contain more natural rubber than regular tyres. Their compounds have been created to remain pliable and soft, giving a higher level of grip in the colder weather conditions while still giving good tyre life. A harder tyre could lead to loss of traction in these colder temperatures.
Likewise, the structure and tread pattern on the best winter tyres are designed to support these qualities. For example, the additional grooves and sipes help to offer grip as well as protecting against aquaplaning. It's equally important to be able and ready to deal with different conditions on the road in winter - while most drivers in the UK can adapt their driving when it comes to ice and snow, they are less concerned with damp and wet roads.
The blocks in winter tyres are designed in different sizes to help the tyre self-clear its own treads ensuring the best grip when it bites into the snow. This pattern ensures the snow leaves the tyre preventing any build up along the tread grooves, which is crucial in winter.
Winter tyres also feature peripheral grooves, which help remove water and slush from under the vehicle increasing stability. As far as tread patterns go, these tyres typically use directional or asymmetric tyres. Directional treads help push snow out while also providing continued contact with the ground, which results in better road safety.
Asymmetric tyres, alternatively, have different characteristics on the inner and outer sides of the tread. The inside segments ensure effective water runoff while the outer edge offers better traction and grip while cornering.