Getting to grips with the right tyres for winter weather

The challenge of driving safely in winter conditions tests more than our driving skills – our tyres take the greatest strain. MICHAEL McALEER went to Rally School Ireland to see BMW test the theory behind the science of winter driving

WE’RE BOTH in identical cars, side by side doing 120 km/h heading up the motorway on a typically wet winter’s day. The only difference is my tyres have worn to 3mm of tread, and yours to 1.6mm. We both jump hard on the brakes at the same time. When I come to a stop, what speed are you still doing? 80km/h. Don’t take your tyres for granted.

In reality most of us did until last winter. In the midst of the last great snowfall, debate raged during the “big freeze” between stranded motorists who blamed their cars, and others dismissed those stuck in snow as being below-par drivers. The truth lies somewhere in between.

BMW, however, are being pro-active. Many of its drivers bore the brunt of the mocking from other motorists – and its dealers the ire of customers.

So it has teamed up with Rally School Ireland in Monaghan to offer a half-day course in winter driving tips. The course is open to all motorists who don’t want to repeat last winter’s mistakes and have a better chance in the slippery stuff.

The school is best known for offering exhilarating rally day experiences, with a fleet of top-level race cars. For the winter school, however, there’s a pair of BMW 316 diesels and a duo of 520d BMWs. One of each model is shod on regular summer tyres, the other on winter ones.

First some qualifiers: no matter how good you are, you’re not going to get a car on low-tread tyres up a snow-clad bank unless you carry it up yourself. Also, a set of winter tyres will not turn your Toyota Yaris into a Land Cruiser. But for the sort of conditions motorists encounter in the estates and side roads of Ireland they will probably give you enough grip to carry on slowly without ending up in either the ditch or the side of someone else’s car.

Regular – or summer – tyres are created from a rubber and silica compound that hardens at lower temperatures. Below 7 degrees centigrade the tyre’s compound hardens so the rubber doesn’t mould into the road: what you have is effectively a solid rubber slick.

David Smyth, owner of the rally school, says that considering the average annual temperatures here we should be fitting winter tyres from October to March.

The benefits of winter tyres don’t end at a balmy 7 degrees however. “There are still big benefits, even at 10 degrees. I personally would suggest, that for people who don’t do big mileage and who don’t drive the car hard with heavy braking, there’s a good case for having winter tyres on all year.”

Admittedly this doesn’t fit with the advice of tyre manufacturers, but Smyth is adamant that in the testing the Rally School has done on tyre grip over the years, the benefits of winter tyres on wet roads are clearly evident.

To prove his point we take to the track. It’s 11 degrees outside but the water-sprayer has been out to wet the track. A small hill road clad in special slippery plastic mimics the snow-covered off-ramp many were stuck on last winter. On the regular tyres we slip and slide, fighting for grip in the same way that many motorists struggled up slip roads during the “big freeze”. Plenty of sound and fury, but going nowhere. On winter tyres, we still slip a little and the electronic traction systems work hard, but we get up the hill.

From here it’s onto a long straight at 60km/h, hitting the wet plastic as we would a sudden icy stretch. Then we slam on the brakes. On regular tyres we slide at least four car lengths more than on winter treads. According to Smyth, at temperatures below 7 degrees there’s a 20 per cent improvement in braking distances in the wet and 10 per cent in the dry.

“If you fit winter tyres you will be able to travel like people in the rest of Europe do in far worse circumstances,” he says. “For me it’s just common sense. All the systems that save you, from stability control to ABS, they all depend on your contact with the road. Winter tyres give you the grip to allow the systems to do their job.”

On most modern cars, with dynamic control systems, the only signal you get is a flashing yellow light on the dashboard. Onboard safety controls such as dynamic stability control and traction control save lives every day, often unbeknownst to the motorist behind the wheel.

“The problem is that people take these systems for granted, or simply don’t know what they do,” says Smyth. That can make motorists complacent. On snow such complacency can be deadly.

During the course you get the chance to test all the various systems fitted to modern cars in a safe environment, learn what it’s like without them, and their limitations. The only thing you’re going to dent is your ego. It’s better to learn how to cope with understeer and oversteer in this environment than on the public road. As I slip and slide my way around the track, a mantra that kept me out of the ditch last Christmas comes to mind: “feet of a ballet dancer, hands of a surgeon.”

In reality I have the feet of a clog dancer and the hands of a meat-cleaving butcher, but at least I know my failings now and what I need to aim for: delicate, gentle movements in steering and throttle are key, along with decent contact to the road.