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Do you need winter tyres this year? And if you change to winter tyres will you damage your car’s fuel efficiency?

If you read our story on How to Buy Better Tyres  you probably already know about rolling resistance and that it accounts for between 20% and 30% of your car’s fuel consumption. (And if you haven’t read the story, it’s a real eye opener, so click here ).

Lately, with the extreme winter weather we’ve had in the UK , a lot of experts have been encouraging us to fit winter tyres, as they do on the Continent. And the word on the street about winter tyres is that they’re noisy and have high rolling resistance, so reduce fuel efficiency. But is it true?

The Facts

The German publication Auto Bild runs highly respected summer and winter tyre tests and publishes the results annually. In their 2010 tests, they addressed this specific issue. They found that  the leading winter tyre was “a fair bit quieter than the summer tyre” and “In the rolling resistance test the summer tyre finished third from last, being beaten by 12 of the winter tyres,”  apparently proving that winter tyres won’t destroy your fuel economy and might even improve it.

How Winter Tyres Work

Unlike many other Europeans, UK car owners prefer large wheel diameters. And large wheel diameters often mean wider tyres. Large diameter wheels give a low down, low profile look that many UK drivers prefer. But, according to the experts, narrower tyres, with their narrower “contact patch” to the ground can give better cold weather mobility as they can make it easier to get through snow, slush and deep water.

Therefore, it may be possible to choose a winter tyre fitment for your car that uses a smaller wheel diameter than your original wheels. The best plan is to check out the possible fitments with your car manufacturer who will know what winter wheel/tyre sizes will suit your car without causing such problems as clearance with the brake calipers.

When changing rim diameters, the tyre overall diameter needs to stay more or less the same, and there needs to be sufficient tyre load carrying capacity to support the weight of the car. When changing to a smaller rim diameter, the new tyres need to have deeper sidewalls (higher aspect ratio) to maintain the same overall diameter. So, for example, a summer tyre on a 19 inch rim will have a shorter sidewall than a winter tyre on a 17 inch rim. But, if chosen correctly, a complete set of either could fit the same car.

Are Winter Tyres Right for Your Car?

Most of us don’t really know about this possibility of fitting different wheel rim sizes. When we need to change a wheel, we open the owner’s manual and buy whatever the manufacturer recommends. But, in fact, most cars can accommodate a range of different rims – large diameter summer rims for fashion and dry handling and a set of smaller diameter winter rims with for narrower, higher profile winter tyres.

In Germany, where they’re used to cold winters and changing to winter tyres is the law, drivers have been doing this for years. Depending upon the part of the UK you live in – and what the weather has been like for the past few years – you may want to consider downsizing your rim diameter. But making the size choice isn’t for amateurs. Consult your car dealer, tyre distributor or mechanic to find out what wheel / tyre sizes are suitable for your car.

And don’t let concerns about fuel economy put you off choosing winter tyres for better mobility. You don’t have to trade one for the other.