Winter tyres: how they work in snow and ice, do I need them in UK, and how do they compare to all-season tyres

Looking at the safety benefits of switching to special tyres as the temperature drops and what it means for your car insurance

After a fairly mild start to the winter the last week has shown how quickly and dramatically conditions can change.

Storm Arwen brought heavy wind, rain and snow to many parts of the country, making the roads treacherous.

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Driving in such conditions requires a more careful approach but many drivers also switch to winter tyres when the weather gets bad.

Here, we explain the benefits of the purpose-made tyres as well as the alternatives and how they can affect your insurance.

How do winter tyres work?

You might think that one car tyre is much like any other but winter tyres are specially designed to cope with cold and wet weather, with unique materials and construction.

While regular tyres work well in warmer weather, once the temperature drops below 7 degrees the rubber in them stiffens, making them less able to grip the road surface. Winter tyres are made from a different compound with more silica, which helps them stay softer and therefore grippier in far lower temperatures.

Winter tyres also have very different tread patterns. Compared to summer tyres, a winter tyre tread has many more grooves cut into it and these are shaped to help to disperse more water along with additional “sipes” that bite more firmly into snow and ice.

Winter tyre treads are also designed to shift to “shake off” snow so it doesn’t build up and affect braking and steering.

Is it worth fitting winter tyres?

Winter tyres can be expensive but they are worth having.

The average winter temperature in the UK is around 4 degrees and we see a lot of rain and snow, meaning summer tyres simply don’t perform as well during winter months, leading to far longer braking distances and less grip in corners.

Tests by tyre maker Goodyear show that on a wet road at 5 degrees, a car on summer tyres will take an extra five metres to stop compared with a car on winter tyres when braking from 62mph. That’s the length of a Range Rover.

On snow or ice the difference is even greater. From 30mph on snow a car on winter tyres will stop in 35m, compared to 43m for summer tyres. On ice from 20mph, a car on winter tyres will come to a stop in 57m rather than 68m - that’s more than two car lengths sooner.

And while it’s an additional outlay at first, every mile you drive on winter tyres is a mile’s less wear on your summer ones.

Do I have to tell my insurer if I fit winter tyres?

In most cases you don’t need to inform your insurer if you fit winter tyres.

A few years ago the Association of British Insurers asked its members to clarify their position on winter tyres, amid concerns that they might be seen as a modification and affect a driver’s policy.

All the insurers confirmed that fitting winter tyres would not affect a driver’s insurance and only three - eCar, Southern Rock and Swiftcover - require customers to inform them if they fit winter tyres.

Some insurers stipulate that any replacement wheels/tyres must match sizes fitted by the vehicle manufacturer as standard or optional equipment and it also goes without saying that they need to be fitted according to the manufacturer’s instructions and be in good condition.

Can I use winter tyres in summer?

There’s no law against leaving winter tyres on your car all year round but we’d advise against it.

The tyres are designed to work best below 7 degrees and at higher temperatures the softer rubber of winter tyres wears out far faster.

The tread pattern also means that winter tyres actually offer worse braking and steering performance on dry roads, so it’s best to switch back to summer tyres once the temperature climbs again.

What are cross-climate or all-season tyres?

While winter tyres are designed specifically for a certain part of the year, in recent years tyre makers have also developed alternatives designed to work year round.

These all-season tyres are intended to offer a compromise between winter and summer tyres. The best cross-climate tyres offer much of the cold-weather performance of winter tyres but are still durable enough to be used in warmer weather and provide better grip and braking in drier, warmer conditions.

They feature a tread pattern somewhere between regular and winter tyres, so are better able to cope with standing water and snow than summer tyres but also offer better performance than winter tyres in warmer months.

They are seen as a compromise, however, and aren’t as good as a dedicated set of winter tyres in the cold or summer tyres in the warm but the best examples do offer a strong balance between the two and the convenience of not having to swap wheels/tyres every year.