Providing cold comfort
Thursday, February 16, 2012
Manufacturers urge operators to fit winter tyres to cope with the threat of snow and ice during the season of goodwill. But is it worth it? Steve Banner investigates
The near-hysterical promotion of the alleged virtues of winter tyres by tyre makers over the past few months is simply a cynical marketing gimmick designed to help them shift more rubber, right?
Wrong, insists Roger Sanders, general manager, technical services, UK and Ireland at Continental Tyres, who says it is instead an honest attempt to ensure van drivers who need to be out in snowy and icy conditions get to their destinations without getting stuck and without having an accident.
Winter tyres also perform well in slush, frost and on roads running with chilly winter rain, he points out. “We’re really talking about any situation where the temperature has fallen below 7°C,” he says.
So what are the differences between winter tyres and their conventional stablemates? One key difference concerns the tread rubber that is used, explains Sanders.
“A winter tyre is designed to be more supple at low temperatures so that it can key into the road surface better and give you more grip,” he says.
Winter tyres, such as Continental’s VancoWinter 2, tend to be more heavily siped (the small slits in the tread blocks) than their spring/summer/autumn counterparts. Spreading under braking, sipes create an ice-scraper effect on the road’s surface in a bid to ensure that the vehicle does not start to slither and comes to a halt more quickly. Open tyre shoulders on the VancoWinter 2 along with wide lateral grooves also aid water drainage and help lessen the risk of aquaplaning.
Hit the brakes at 30mph on standard tyres in adverse conditions and your braking distance could increase by up to 31% – 13m – compared with what you should be able to achieve on winter rubber, reckons Continental.
Sanders, however, is eager to explode one myth about winter tyres – that their design, and the tread rubber used, means they wear out more quickly than mainstream varieties. “That may be the case if you use them in the summer, but not if you use them in the winter,” he observes.
Indeed, Continental reckons that its VancoWinter 2 offers as much as 30% extra mileage potential during the winter months when compared with a conventional van tyre. This helps offset any mileage lost during June, July and August.
Some light commercial operators, especially in Scotland and the north of England, may take the view that they would prefer to leave winter tyres on their vehicles all the time – they can be used safely year-round – and accept any wear penalty. That way, they do not have to go to all the bother of changing tyres and wheels the minute the first snowflake appears and are instead instantly ready to do battle with the elements. Nor do they have to worry about where they are going to store all those sets of winter tyres when they are not in use.
Meanwhile, Sanders is anxious to stress that an M+S (mud and snow) marked tyre is not the same as a true winter tyre and does not offer the same level of performance. “The latter can be identified by a pictogram consisting of a snowflake suspended in an outline of alpine mountains,” he says.
One major operator that has opted to equip some of its light commercials with Continental winter tyres is British Gas. It has fitted them to 120 Volkswagen Caddy vans to ensure that help can reach customers in poor weather.
General manager, fleet, Colin Marriott says: “Our engineers say they have been able to complete a normal full day’s work even in the most adverse of conditions.
“When snow blanketed the UK in January 2011, the Continental winter tyres really proved their worth and in some cases the front-wheel drive Caddy outperformed 4x4 vehicles fitted with standard tyres.”
Designed with electric cars in mind, Continental’s low rolling-resistance Conti.eContact will be available as a winter tyre from 2013 onwards. A Conti.eContact suitable for electric vans could be added to the line-up too.
Operators should ensure their tyres are maintained properly. Both standard and winter tyres will perform better if they are inflated to the correct pressure, do not have badly worn/borderline-illegal treads and do not suffer from cuts or suspicious bulges in the sidewall, which is evidence of internal damage.
No matter which season they are designed for, from 1 November 2012 all new tyres sold in Britain and produced after 1 July 2012 will have to be accompanied by labels giving standardised information on rolling resistance, wet grip and noise (see picture below). They will be revised in 2016.
Such labels are likely to prove invaluable to customers says Continental marketing manager, commercial tyres, Tracey Hyem. “If you are looking at rolling resistance, for instance, then a tyre graded Class C could use up to 10% more fuel than one graded Class A,” she points out: worth bearing in mind given the high cost of diesel.