Winter Tyres - The Main Arguments - FAQs

Winter Tyres are for folk who live in the cold north of Scotland, are they not?

Winter tyres are a big seller across Europe, even Italy (yes, Italy). Part of that is due to the potential for severe weather conditions in Central Europe and in the higher altitudes such as the Alps. However, in some countries the law demands that winter tyres are used during the winter months.

In Germany insurance companies have been known to refuse to pay out where a driver has not fitted winter tyres and had an accident. In Scandinavia it would be virtually impossibly to travel any distance without winter tyres. But in the Uk, is there a real need?

If we go back to the basics of how a tyre functions we will understand that a tyre's grip and traction are determined by its tread compound and its tread pattern (in particular). For a tyre to have grip the rubber needs to be supple in order to flex to grip the road. If the rubber hardens, it loses its grip sooner rather than later. The tread pattern also impacts, and essentially, in slippery conditions the tread with the most leading edges and channels will offer the greater grip. So, if we take a conventional summer tyre with a limited block pattern, and a soft summer compound that sticks to the road in "summer" conditions. How will that fare in the winter? For one, as the temperature drops the tyre tread will stiffen - reducing grip. In wet, or snowy conditions the summer channelling may not pump away sufficient water and the tyre is prone to aquaplaning at an earlier stage.

So, how do we address those issues? We get the tyre designers to produce a tyre with a compound that remains sticker for longer in colder temperatures, and we ask him to design in more leading edges through a blockier design with lots of siping (slits to add leading edges and pump water. We then have a cold weather or, winter tyre. That performs better in the cold and wet.

How important is that to us in the UK?

On the few days that we do have snow in the UK most motorists adapt their driving to suit (and the highways very quickly turn to gridlock). However, the visible differences between driving in damp conditions in summer and in winter are not noticeable and most drivers do not adapt to winter driving conditions in the wet.

There is a point at which winter tyre compounds offer better adhesion than summer tyre compounds, and that is when the temperature drops below 7 degrees Celsius. This is the point at which summer tyres start to harden and their performance drops. Softer winter tyre compounds keep sticking better for another 15 degrees or so. Those conditions (below 7 degrees) apply in the UK at peak driving times for a surprising four months every year.

That means that in lower temperatures the winter tyres can save as much as 11metres braking distance at 50kph. That's a whole trucklength.

When put in that context winter, or cold weather tyres can be a lifesaver, they can certainly help minimise the risk to your insurance premium over the winter months.

Two Camps

Traditionally, winter tyres were big, chunky tyres that often saw service on rally cars. Nowadays things are a great deal more complex and it is recognised that the tyre needs to do more than just grip in the snow.

One train of thought is that tyres should have a tread pattern that is self cleaning and doesn't retain snow and ice, so that there are always fresh leading edges to grip a snow covered surface. The other is that the tread should be designed to retain snow and ice to improve all round grip. Now that latter case takes some consideration. It is explained thus; make two snowballs and then rub them together. The friction between the two snowballs is so great that both disintegrate in your hands. Snow sticks to snow. Try rubbing a snowball on a tyre, it just slips off. So, the theory goes that snow stuck in the tread of a tyre can improve its performance in the snow. You pays your money and you takes your choice.

The same theory does not quite apply to ice though.

What about the cost?

On the face of things you are buying two sets of tyres, so your costs are doubled, but, since you are splitting the mileage done on each set of tyres you extend their life expectancy. Anecdotal evidence suggests that on buying a new car and fitting it with winter tyres over the cold weather period and summer tyres at other times, not only does the driver have improved winter safety but his tyres actually last longer. Over a five year period it is claimed that running winter and summer tyres can save the cost of a whole replacement set of tyres. Of course that is anecdotal and depends upon mileage and driving style.

So what do I do with my spare tyres?

Tyre storage is indeed an issue. The tendency is to store spare tyres at the back of the garage until you need them. The safe option is to keep them on spare rims (which makes sense to protect you summer alloys anyway) and keep them in a cool dark place where they can be rotated from time to time to prevent weak spots developing. Or, you could approach a local tyre dealer and ask him to store your wheels and tyres for you. Tyre Hotels are common in Northern Europe, but there are a few in the UK.

And if I use winter tyres in the summer?

You will obviously find greater wear on your winter tyres because at summer temperatures they are much softer than summer tyres, However, that in turn makes them stickier, so there is no real reason why you should not use winter tyres all year round is you wish, and you don't mind the higher noise level, and the greater wear and tear.