With snow reaching Switzerland’s plateau this week, some motorists may regret delaying the switch to winter tyres. The change need not wait for ice or flurries: the tyres are designed for cold conditions generally and work best when temperatures drop below 7°C.
Calling them snow tyres is misleading. Switzerland sometimes sees weeks of sub-zero temperatures without a single snowflake. Waiting for the first snowfall, is a poor strategy.
The consequences are well known. Summer tyres stiffen in cold weather, lengthening braking distances and reducing grip. It’s generally recommended to switch to winter tyres from October to Easter, regardless of the weather. Winter tyres have softer compounds and deeper tread patterns that stay pliable in the cold.
Switzerland imposes no legal obligation, but insurers may refuse cover if an accident is judged to result from inappropriate equipment. France requires winter tyres or chains in all mountain départements from 1 November to 31 March. Italy’s rules vary by region: most require winter tyres or chains from 15 November to 15 April, while Aosta starts on 15 October.
Keeping winter tyres on year-round is a false economy. They wear quickly in warm weather and lengthen braking distances in summer. All-season tyres have improved but remain a compromise: They cannot match winter tyres on ice or snow, nor summer tyres in heat.
Older tyres present another risk. After five or six years the rubber hardens even if the tread remains deep, reducing braking performance. The age of a tyre can be found by reading the DOT code stamped on its sidewall. The last four numbers show the date of manufacture.
For example: DOT 1A9B 3CJR 2619 is a tyre made on the 26th week of 2019.
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