Tyre wearing
 

Drivers tend to overestimate the condition of their winter tyres. To avoid the problem of inaccurate visual estimates, Nokian Tyres has developed the DSI (Driving Safety Indicator), which accurately displays the remaining tread depth. The DSI system displays the groove depth in millimetres. The numbers clearly show whether the tyres are safe to drive and how much tread is left on the tyres.

If the studs in the tread are loosely attached to the tread, the grip of the tyre is significantly weakened. If the studs sway, they won't grip firmly on ice and the tyre won't perform well on slush and snow. If a lot of studs have worked their way loose unevenly from the different tyres, their grip may be dangerously low. The number of studs on the tyres mounted on a car should not differ more than 25%.