Bridgestone Feature - Tyre Warmers

Think of a cold winter's night. You stare at your bed - it's going to be freezing under the sheets and you can't face slipping under the duvet. Eventually you do and there are five minutes of skittish unpleasantness as you try to generate warmth.

Now think of the same winter's night, but this time your bed is wrapped in a warm electric blanket. Suddenly you cannot wait to jump in and enjoy its warmth.

The same analogy can be applied to Formula One tyres. Without prior heating, Bridgestone's tyres would take several laps to reach their optimum operating temperatures - several skittish, slippery laps that would inevitably end in the gravel trap, and with zero Championship points.

Cold conditions, be they in bed or on the racetrack, are not good. That's why all of Bridgestone's F1 teams pre-heat their tyres in custom-made tyre warmers. These warmers work like electric blankets and heat the rubber to between 80-100ºC. This not only ensures optimum grip levels from the moment the car leaves the pit lane, but optimises tyre pressures as well.

"On stone cold tyres," says Toyota star Jarno Trulli, "the car would be very difficult to drive. If you went at anything like close to racing speed, you'd be straight off the circuit."

Mike Drury of the company MA Horne first introduced electric tyre warmers in 1985. Teams had tried various methods to pre-heat their tyres prior to then, including wrapping them in black bin liners, but it was Drury who introduced the first bespoke 240-volt blanket.

He now supplies the majority of F1 teams, including Bridgestone-shod Ferrari, WilliamsF1, MF1 Racing and Super Aguri F1, and has a large presence in other categories of motorsport.

While the principle of the blanket has remained largely unaltered over the years, the product has evolved. It now heats the sidewall and internal rim of the tyre as well as the tread area, and the cords used to tighten the blankets are made of Kevlar to stop them burning.

"The teams realise how much of a difference tyre pressures make to the handling of the car," says Mark Drury, son of company founder Mike.

"We developed our product to cover a larger area of the tyre in an effort to speed up the process of getting the pressures up to operating temperatures."

As a rule, it takes approximately one-and-a-half to two hours to heat up the tread area of the tyre and for the pressures to reach their optimum levels. The tyres are then put on the car with the tyre blankets still attached, except at a pit stop, when the blankets are removed 15 seconds before the car arrives in the pit lane.

The blankets cost approximately £2200 per set, and with the teams needing between 36 and 40 sets each, they are a costly - but vital - feature of the F1 pit lane.

And they are set for further development as teams experiment using carbon sheets inside their blankets in an effort to get a more even spread of heat across the tyre. However, the blankets are at least durable - Ferrari still uses the blankets that Drury made for them in 1996.

"We don't need to send an engineer to races," says Drury, "because we never have any problems with our blankets." Perhaps he should expand into bed blankets as well.