30
Sep 2011
Winter tyres: the debate
There are a number of issues in the motor industry that seem on a perennial loop in the sense that they surface, are discussed, inspire angry and then disappear for a while, only to resurface at a later date.
There’s the ongoing speed camera debate, EVs versus hydrogen/alt-fuels and then there’s winter tyres one – a favourite that surfaces in September every year.
Tyre manufacturers and car-makers like to start pushing winter tyres and their benefits in cold weather with cold weather approaching, especially with colder winters of late, with a particular focus on braking distances and all-round performance in colder weather.
But drivers frequently counter that winter tyres are little more than an unnecessary choice in the UK and represent a cash cow for tyre manufacturers.
Last year, demand for winter tyres far outstripped supply and there are ever-more frequent calls to make winter tyre fitment compulsory in the UK – as it is in parts of continental Europe.
With another harsh winter predicted and at least one premium tyre manufacturer ramping up its production of winter tyres from 350,000 to half a million this winter; car-makers and safety organisations pushing winter tyres and harsher winters now, seemingly, the norm, we’ve weighed up both sides of the argument.
So, low-temperature life-savers or pointless pocket-liners? Find out below whether winter tyres are worth the effort, and expense.
Winter tyre conditions
Despite looking the same – namely black and round – winter tyres are quite different to summer tyres in terms of compound, tread and design. They’re optimised for operation in temperatures of seven degrees Celsius and below.
The majority of motorists associate winter tyres with snow and ice, however winter tyres outperform summer tyres in any conditions below that seven degree figure.
So whether on dry roads, damp roads, icy or snow covered roads, winter tyres should cope better than summer tyres if it’s cold enough (less than seven degrees Celsius).
Winter tyres: supporting statistics
According to tests by Continental, a car travelling at 20mph on icy roads, with winter tyres, will come to a halt 11m before the same car travelling at the same speed but on summer tyres.
On snow covered roads a car with winter tyres, travelling at 30mph has a braking distance of 35m whereas the same car, travelling at the same speed but on summer tyres will stop eight metres further down the road.
With winter tyres, it is perhaps obvious that they will operate better in stereotypical winter climes; however on wet roads and winter tyres at 62mph a car’s braking distance is 65.7m at five degrees Celsius; on summer tyres that distance is increased by 4.8m.
What Car? has also found that cars shod in winter tyres and travelling on sheet ice at 12mph stopped after 12.5m - some 6.5 metres shorter than the same car in the same conditions on standard tyres.
What’s the difference between winter and summer tyres?
Winter tyres are as different to summer tyres as black pieces of rubber can be and the differences cover three basic areas: compound, tread and sipes.
In terms of compound, they contain a higher proportion of natural rubber than summer tyres, which means they are softer and more flexible in lower temperatures.
Summer tyres will begin to stiffen and harden at seven degrees Celsius, meaning that rather than key into the road surface, they will ride along the top of the bumps and grooves of the road. A winter tyres is softer and more flexible so will key into the roads surface giving more grip.
Tread pattern is also different on winter tyres because it is much wider than on summer tyres. That means it picks up snow as the tyre comes into contact with it, pressing it into the grooves. That may sound counterintuitive but it actually increases grip because there is a lot of traction between snow and snow.
The final difference is an abundance of sipes – slits in the tyres rubber – that provide more points for the winter tyre to bite into the winter road surface and thus provide more traction and control.
Why not use winter tyres all year round?
The problem with winter tyres is that they do not perform as well as summer tyres in temperatures of seven degrees Celsius and above.
How well do they work in warmer conditions?
While winter tyres will work in warmer conditions, they’ll bring with them a number of drawbacks as the weather gets hotter.
Their strength in winter is based on their ability to remain soft and flexible in cold conditions however the flipside is that in warm weather, these tyres become even softer and will wear out even quicker as the temperature rises.
In the UK, where weather is about as predictable as a teenagers mood swings, that puts motorists immediately on the back foot and out of pocket because tyres will need to be replaced sooner and will impact on fuel economy in the same way under inflated tyres do.
Why don’t more drivers use winter tyres?
The statistics provide an overwhelming argument for winter tyre use, however an alarmingly small number of UK motorists fit them during winter months.
That’s because relatively few motorists are aware that winter tyres exist or aware at the difference they could make in wintry driving conditions. That’s changing due to tyre safety month and a number of manufacturers and tyre makers who are investing a lot of time and money into increasing exposure for winter tyres.
That’s borne from the advantages they bring in cold weather but there will always be the money making argument to counter that point.
Wear, tear and practicality
As well as a lack of education, motorists are also put off winter tyres because of price, with one set of tyres a year proving costly enough for some.
There is also a concern that winter tyres, because they are softer, will wear out faster than summer tyres however there is little evidence to support this theory if winter tyres are used in the correct conditions.
Tyre makers direct winter tyre users to change them as soon as the bad weather has gone because winter tyres perform poorly in warmer weather and impact on fuel economy.
However, if used in appropriate temperatures, there is little evidence to suggest that they will wear out quicker than summer tyres.
Tyre manufacturers also like to point out that whilst your winter tyres are in use, your summer tyres are in storage and vice versa. That means that only one set is being worn at a time as opposed to the same set being worn down all year round. That in itself throws up another issue of storage space.
Tyres aren’t small and there are four of them which can automatically rule some motorists out because they do not have the space for them.
Winter tyre pricing
A new set of winter tyres can cost anywhere between £200 and £600, but if that proves too expensive there are a range of alternatives for motorists.
In recent years, snow socks have become increasingly popular because they are cheap and require little effort to be fitted.
They are wrapped around the tyre and provide more grip than standard tyres because of their composition. They can be bought for around £50.
Either way, winter tyre provision is more expensive than not having winter tyres at all and there’s less fuss in terms of fitment, too.
Why are winter tyres more expensive than summer tyres?
Price is perhaps the biggest bugbear when it comes to winter tyres and one of the main reasons critics believe they are little more than a cash cow.
According to Continental, there is no escaping the inflated costs of winter tyres until they become more popular and are produced in similar volumes to summer tyres.
Tim Bailey, head of safety at Continental, said that summer tyres are far cheaper, per tyre, because they’re produced in much lower volumes than regular tyres.
“We produce winter tyres in much lower volumes than summer tyres – so there aren’t the economies of scale with producing winter tyres. As a result they’re more expensive for us to produce."
Another reason winter tyres are more expensive is because of their compound which is more advanced than summer tyres.
As mentioned, winter tyres use more natural rubber than summer tyres to remain flexible and soft in cold temperatures. Natural rubber is more expensive than synthetic alternatives, according to Bailey, driving the price of winter tyres up.
Will winter tyres invalidate my warranty?
There have been stories in the recent past of winter tyre fitment invalidating insurance policies, however as long as they are the correct size and type for your car, there should be no issue with insurers because they will not be deemed as a modification.
The Society of Motor Manufacturers and Traders (SMMT) exploded this myth last year in the following statement:
“SMMT has clarified that the fitment of winter tyres does not constitute a modification that will affect premiums.
"SMMT is recommending motorists use winter tyres to improve grip and overall stopping distances during harsh winter driving conditions and is urging drivers to seek further advice from their local franchised dealer."
There are also a number of myths surrounding winter tyres and how they can damage road surfaces, thanks mainly to Transport Secretary, Phillip Hammond, who supported the claim last year.
Hammond was lambasted for his comments by a number of organisations, but it was Stuart Jackson, chairman at Tyresafe, who led the way, saying: “Mr Hammond’s comments show a complete lack of understanding about modern winter tyres which are the ideal solution to the type of weather we are currently experiencing."
Should they be compulsory?
As mentioned, winter tyres are being championed by an increasing number of groups, brands and manufacturers who agree that they offer increased grip and traction in most winter weather conditions.
Seat is the latest manufacturer to back the cause with Nigel Griggs, head of aftersales in the UK, stating:
"The value of winter tyres really cannot be overestimated. Research from one tyre manufacturer suggests drivers may be as much as six times more likely to have an accident in the winter than the summer, so waiting for the first snowfall before making the switch could be a major false economy."
Ford, Saab and Mercedes Benz are also firm backers of winter tyres, along with the majority of volume manufacturers, and they have been joined by a growing number of industry figures who have urged the UK government to make winter tyres compulsory as winter sets in.
Last year, What Car? carried out a number of tests with winter tyres and then editor, Steve Fowler, concluded: “If climate change is going to bring us much colder winters, we believe the government should look at making a tyre change compulsory in winter, as it is in most other countries."
Despite a growing call to arms for compulsory winter tyre fitment, the UK government has remained unmoved in terms of legislation with Transport Secretary, Hammond saying that winter tyres were not “appropriate" in the UK given the short amount of time that snow and harsh winter conditions are around.
The government’s reluctance to make winter tyres compulsory has also fuelled the argument that they are nothing but a marketing ploy because, if they were genuinely safer, surely UK motorists would be forced to fit them?
Should I buy winter tyres?
According to Continental tyres, drivers are six times more likely to be involved in an accident in winter than in summer months.
There are also a range of figures which show that braking distances are significantly reduced in temperatures below seven degrees Celsius on winter tyres.
In 2010, the mean winter time temperature in the UK was 1.6 degree Celsius, according to the Met Office and between 1 December and the end of February, temperatures never exceeded seven degrees Celsius.
However in autumn 2010 between the 1 September and the 30 November, temperatures averaged 8.9 degrees Celsius leaving motorists in a tricky situation when it comes to winter tyres.
Their advantages are obvious in suitable weather conditions and if tyres are changed in accordance with temperatures they are the obvious choices in terms of safety.
If, however, they are used inflexibly for a set period of time, motorists could see drawbacks in terms of wear and tear, fuel economy and performance in warmer conditions.