Is that snow I see!

Posted: September 20, 2011 in what next?
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Winter tyre advice

Gripping Facts.

In countries where severe winter weather conditions are more or less guaranteed, it is quite normal for drivers to switch to winter tyres for the duration of the cold season even though it is only a legal requirement in Austria, Finland and Sweden. The practice has not been taken up in the UK because harsh winters are quite unusual here – in spite of our experience over the last two years. However, the benefits of winter tyres are not restricted to snow and ice covered roads – low temperature alone seriously impairs the performance of standard tyres. Manufacturers are also fitting wider wheels and tyres to cars, which are less suited to slippery winter conditions, so it may now be time for UK motorists to consider the benefits and drawbacks of seasonal tyres, or whether they should invest in snow chains or some other form of traction aid for when our weather turns arctic. The options are Winter Tyres, All Season Tyres, Snow Chains and Snow Socks. Studded tyres are not considered here as they are no longer generally available in the UK. Potential damage to roads and development of non-studded winter tyres has rendered them obsolete.

Winter Tyres.

The most obvious difference is the tread pattern; winter tyres have wider grooves and narrow slits at the edges of the tread area, which combine to give better grip on snow and ice. However, a much more important difference is not so easily seen. The rubber compound used for the tread section on standard tyres gets stiffer as the temperature drops; stiffer rubber results in less grip and below 7o Celsius, the grip starts to reduce as the temperature gets lower, although most drivers won’t really notice much difference until the roads have dropped to near freezing point. Winter tyres have a different compound which stays soft, bendy and grippy to well below zero. Tyres made with this compound will carry either a snowflake or a mountain as a symbol on the sidewall. Winter tyres undoubtedly have far better grip in snow and ice and allow drivers to get around quite easily in conditions that make driving on standard tyres impossible, while maximum braking and cornering performance is also retained on dry roads at sub-zero temperatures.
However, there are drawbacks. For a start, most European drivers who do make the switch to winter rubber have two sets of wheels and tyres so that they can change over quite easily with nothing more than the vehicle’s wheelchange kit. That means an initial outlay for a new set of wheels as well as tyres. Even getting steel wheels for the winter, instead of the alloys the car comes with, will still set the owner back about £500 or more by the time the tyres are fitted, and that outlay will apply every time the car is changed for a different model. Changing over to winter tyres permanently to save the outlay for new wheels is possible, but the tyres won’t have the same grip once the weather warms up, they’ll also be noisier, wear out more quickly and the car will use more fuel, so two sets of wheels is really the best option. Somewhere to store the extra set of wheels is another consideration, although some tyre outlets do offer a complete winter tyre service where they swap the tyres over and store the set not in use.

So, should we all invest in a set of winter wheels and tyres? The UK government shows no sign of making it compulsory, and there are good reasons for this. Firstly, extremes of cold, snow and ice are the exception here. Even though the grip of standard tyres starts to reduce below 7o Celsius, the reduction does not become significant until the roads are around freezing point, which only happens regularly in a few hilly or remote areas of the UK. Many motorists also take heed of public warnings and avoid driving in poor conditions, so all things considered, compelling every driver to buy and store a spare set of wheels and tyres would be imposing an unnecessary expense on the vast majority.
Nevertheless, a set of winter tyres is a sensible option for some UK motorists, for example people who live at high altitude or in remote areas. For the rest of us, whether the cost is justified very much depends on personal circumstances such as annual mileage, the risk of extreme weather conditions and whether you have the option to avoid driving in them.

Does the Different Tyre Specification Matter?

If you do go for winter tyres, the speed rating will be lower – this is denoted by the letter before the “R” on the sidewall. This is perfectly acceptable, as the maximum speed is still well above national speed limits everywhere apart from some German motorways and in wintry conditions speeds should be kept lower anyway. The lower speed rating will not cause a car to fail the MOT test and should not affect your insurance. Nevertheless, there have been stories of insurers raising premiums when winter tyres are fitted. The Association of British Insurers has confirmed that, “The major motor insurers have all confirmed that they would not class fitting winter tyres as a material modification and it would not impact on the premium. The one condition would be that they would expect such tyres to be fitted by reputable garage/dealer, in accordance with the motor manufacturer’s specifications.”
The ABI also recommends that you inform your insurer if winter tyres are fitted, just to be on the safe side.

All Season Tyres

A compromise solution available to drivers who want some extra grip for the winter, but don’t want the expense or inconvenience of two sets of wheels is to fit a set of All Season tyres. These have the more flexible rubber compound of winter tyres, but with a tread pattern that is more suited to a range of weather conditions rather than being specifically tailored to snow and ice. As a result, they can be used all year round as the name implies, but like any compromise, they are not perfect; they will not be as good as standard tyres in summer or as grippy as winter tyres in snow and ice. Because they use the low temperature rubber compound, they should have the snowflake or mountain symbol, but may also have a sun symbol or be marked “M+S” – this does not imply they are made by Britain’s favourite underwear store, but stands for “Mud and Snow” to show that the tread pattern is suitable for these conditions. (The alternative, S+M, has even more dubious connotations). Unfortunately there is no international standard defining what an All Season tyre is, so beware of tyres sold as “All Season” that do not carry the snowflake or mountain symbol – they will be made from standard rubber and will lose grip below 7o Celsius just as standard tyres do, whatever tread pattern they have. Just as with winter tyres, if you fit All Season tyres, you should inform your insurance company, although it should not affect your premium in any way.

Tyre Condition

Whatever tyres are fitted, regular checks of tread depth and pressure are even more important in winter. Performance in snow, ice or sub-zero conditions will be significantly reduced if the tread depth falls below 3mm. Pressure should be checked with the tyres cold – that means they should have been driven no more than a mile. Set the pressure to the value specified by the vehicle manufacturer or the tyre maker if different pressures are specified for winter tyres. Do not reduce pressure to increase grip. Tyres with low pressure do not have any more grip, but are prone to overheating and blowouts, and changing a wheel in freezing conditions is both unpleasant and dangerous.

Snow Chains and Socks

A useful alternative to changing tyres is to carry snow chains or snow socks to fit when the snow gets deep. Most people are familiar with the idea of chains, but snow socks are a fairly recent innovation; made of a strong fabric which grips snow, they are a stretch fit over the tyre. Either of these can be used with standard tyres and they fit quite easily into a corner of the boot, or corner of the garden shed in summer, so there are no major storage isssues.
Snow chains are more effective, but have several drawbacks. First, check that your vehicle can be fitted with them! Chains increase the width of the tyre and may foul the suspension, the brake, or the wheel arch on a turn. The owner’s handbook or a dealer will be able to tell you if chains can be fitted. Chains can also be quite a chore to fit and anyone buying them should practice fitting them before the bad weather sets in, or at least try fitting them at home as soon as they’re purchased, to understand what’s involved before trying to get them on in a blizzard. A clear road surface will be damaged by snow chains, so you mustn’t fit them until there is a blanket of snow and you must stop as soon as the snow has gone and remove them. It is an offence to use chains or studs when they will damage the road surface, which is why studded tyres are no longer generally available – removing the chains when the snow clears is a lot simpler than changing all the wheels. You can get away with fitting chains to the driving wheels only, but this should be an emergency measure; if you know that you will be driving for some distance, or regularly on snow, fit chains to all wheels. Expect to pay around £50 for a set of economy chains to carry in the boot for emergencies, up to a couple of hundred pounds for a heavy duty set suitable for regular use.
Snow socks, on the other hand, are slightly cheaper to buy – typically about £40 upwards – they are much easier to fit and will give sufficient grip for most snowy conditions in the UK. They do not damage roads, although they will wear out very quickly if driven for any distance on tarmac, so should be removed as soon as it is safe to do so.
If you venture abroad with your car for skiing holidays, you will be familiar with signs telling you that chains must be used and there is a legal requirement that you carry them, even if there’s no snow. In this case, chains means chains and although many local may use socks, you should still carry chains to avoid the possibility of a fine.
Both chains and socks should be washed as soon as is practical after use to get rid of dirt and salt that will otherwise corrode or degrade them, and they are both a nightmare to fit for the first time in a blizzard, so do study the instructions and practice fitting them in the dry.


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