When should you fit winter tyres?

Winter tyres aren't only for snowy roads. Their main difference is that the rubber stays soft in cold weather. So rather than waiting for snow, it makes more sense to look at the thermometer when deciding to switch to winter tyres.

The 7 degree rule

The rubber compound used in summer tyres hardens as the air gets colder. Below about +7 °C, a summer tyre can't "grip" the road well enough and braking distances become noticeably longer. The rubber of a winter tyre, by contrast, stays flexible at low temperatures.

The practical rule is: switch to winter tyres when morning and evening temperatures start regularly dropping below 7 °C. Switch back to summer tyres when temperatures are regularly above 7 °C. In warm weather, winter tyres wear faster and don't brake as well as summer tyres.

In Turkey this date varies a lot by region. Winter starts at the end of October in Eastern Anatolia but may not arrive until December in coastal cities.

Why is the winter tyre tread different?

Winter tyre treads have many fine cuts (sipes). These sipes:

• Hold snow between the tread blocks. Snow grips best on snow.
• Break through the thin film of water on wet and icy surfaces.
• Give the tread more edges in contact with the road.

Tread depth is also usually greater than on summer tyres. Deep tread is needed for the snow and slush channels to work.

The difference between M+S and 3PMSF

M+S (Mud + Snow)

M+S means "mud and snow". It is a marking with which the tyre manufacturer declares that the tread pattern is suitable for these conditions. There is no independent test requirement. Many SUV summer tyres and all-season tyres also carry M+S.

3PMSF (Three-peak mountain snowflake)

The symbol showing a snowflake inside a three-peaked mountain indicates that the tyre has passed a standard snow traction test. This is the marking to look for on a true winter tyre. Many European countries require this symbol under their winter tyre rules.

Some tyres also have a separate ice mountain symbol showing performance on ice. This is found on tyres developed especially for very cold and icy regions.

Are winter tyres mandatory in Turkey?

In Turkey, winter tyre rules are set by decisions of the Ministry of the Interior and provincial governorates. They mainly cover commercial vehicles (such as lorries, buses, minibuses and taxis) and usually apply between 1 December and 1 April. Governorates can change these dates depending on weather conditions. There is no nationwide requirement for private passenger cars, but local decisions and enforcement during snowfall may vary.

The rules and dates are updated from time to time. Follow the announcements of the governorate of the province you are in.

Another thing to watch with winter tyres is tread depth. For a winter tyre to be effective in snow, it needs deeper tread than the legal minimum. In Turkey a lower limit of 4 mm is generally applied for winter tyres.

Are all-season tyres a solution?

All-season tyres are a compromise between summer and winter tyres. All-season tyres carrying the 3PMSF symbol can be a sensible choice in cities with mild winters and little snow. But in regions with harsh winters they don't replace a true winter tyre. In summer they also don't brake or corner as well as a summer tyre.

When buying winter tyres

1. Size: Choose one of your car's factory sizes. Using a wheel one inch smaller with a higher-profile tyre in winter is common and sensible (the overall diameter must be kept the same).
2. Symbol: Look for the 3PMSF marking.
3. Load index: Don't go below the factory value.
4. Speed rating: It can be lower than the factory value, but put a speed limit label on the dashboard.
5. All four at once: Don't fit winter tyres only to the front or only to the rear. The car will lose its balance.