Here's How Winter Tyres Work

Winter can be a tough time for any car, with the onslaught of grit, salt and general moistness paving the way for unwanted corrosion, accumulations of clotted road grime and slippery driving conditions. Thankfully, there are a few ways in which you can prepare your car for the worst of winter, the most obvious of those being a set of winter tyres.

Although they can be costly and will normally sit dormant in your garage for the vast majority of the year, they can literally be lifesavers. So how do these special bits of rubber keep your car on the straight and narrow?

Winter brings with it wet and icy roads that standard road tyres are simply not designed to effectively deal with. Tyres are manufactured to operate at certain optimum temperatures, with the temperature affecting the stiffness of the rubber compound and giving it the flex needed to maximise friction between the rubber and the road surface.

Winter tyres are made up of a softer compound than standard tyres by using much more natural rubber within their construction. This means that – as temperatures dive to below seven degrees centigrade – the rubber stays malleable rather than becoming rigid, keeping good contact with the road surface and therefore creating much-needed friction. Braking distances are decreased and general grip is increased compared to standard tyres.

Winter tyres also feature more grooves and crevices within the tread design than summer boots. Due to the sheer amount of water and even snow covering the roads during winter, standard tyres can often have a tough time wicking water from the tyre contact areas which leads to the coefficient of the friction of the tyre suddenly decreasing, making the car quickly uncontrollable. This is amplified further when snow is involved, with the clogging of the grooves effectively resulting in slick tyres and putting you and your car in a world of hurt.

Known as ‘sipes’, the rubber channels moulded into a winter tyre’s construction are much more efficient at displacing the large amounts of water and snow that you drive over. The centripetal force induced by the spinning of the wheel allows the grooves and sipes to channel fluid away from the contact area of the tyre. Sipes can also be used as simple teeth to grapple snow much more effectively than a normal summer tyre, biting into even the most-compacted snow covering the road.

Unfortunately, the rubber compounds used in winter tyres are designed only to work at low temperatures. Winter tyres do not work anywhere near their optimum performance when used in spring or summer conditions, as the rubber becomes far too soft and heats up due to the increased friction with the tarmac they’re driving over. As they soften, the sidewalls begin to lose stiffness, making handling less responsive.

On their own, winter tyres can only do so much in the way of keeping your car driving as it should in crappy conditions. The modified rubber isn’t going to pile-drive you through the heaviest of Scandinavian snow storms or completely eradicate all forms of slippage over large expanses of black ice. In countries where ‘winter’ means multiple feet of snow, much more extreme measures need to be looked into in addition to winter tyres, like chain covers for your wheels to bite into the heavily-compacted snow and slush or even spiked tyres.

In this day and age, you can buy winter tyres for virtually any size of wheel on the market; I’ve even heard of a Lamborghini Aventador owner who decided to daily drive his raging bull throughout a Swiss winter, so slapped on some 335/30 ZR20 winter shoes! Due to this mass-production, we no longer have to venture into the world of 4x4s to get to work when the going gets tough and can make a good stab at getting even the smallest of city cars through a blizzard to our place of work.

So should you get winter tyres? Well, as mentioned above, it can come down to the winter conditions that you are used to in whatever country you live in. For example, here in Scotland, I wouldn’t outlay over £100 a tyre for a full set of winter shoes for my MX-5. On the other hand, tyre manufacturers now offer a happy medium through ‘all weather’ rubber which is a much more appetising prospect. Not only will these tyres work in the spring and summer due to only slight softening of the compound, but the added sipes will also see your car deal much better with the odd flurry of snow and heavy rain throughout the winter months.

Whether you fork out for a full set of winter tyres should come down to the weather you plan to be driving in and your relative budget. Although the vast majority of us seem to just take our chances with standard tyre treads and compounds all year round, the added benefits especially in safety may sway you one day towards buying a set. Also, not only will they reduce wear on your standard tyres (saving them for summer hooning), they will also allow you to drive even the most-extreme of dailies, knowing that you won’t end up spinning into your neighbour’s garden while reversing out of the driveway.

Do you switch to winter tyres once the leaves fall from the trees? What is the most extreme car you’ve seen sporting winter shoes? Comment with your thoughts below!