Less risks after new regulations

After a year of abstinence in Formula One, when a set of tyres had to last for both qualifying and the race and a change was only permitted in an emergency, drivers can now make the most of their tyres' performance again.

In 2006, Formula 1 tyres are still a crucial factor in deciding between victory and defeat; performing with magical prowess while subjected to extreme loads.

By returning to the old tyre regulations - and so more frequent pit stops - Formula 1 has not only become more interesting but also safer. Now, the drivers are no longer tempted to continue driving on worn or damaged tyres and, in the worst-case scenario, risking an accident simply to avoid losing time with an unscheduled tyre change. But the new regulation is not carte blanche for the drivers.

"It's true that we can drive a bit more aggressively again," says Mark Webber, WilliamsF1 driver, "but, of course, we still have to make sure that we last the distance with the tyres."

The first thing the teams must sort out - before worrying about race strategy - is their tyres. Given the range that is permitted by the tyre clauses in the Formula 1 regulations, they are really spoiled for choice.

For a grand prix weekend, no fewer than seven sets of dry weather tyres are available for drivers, plus four sets of wet weather tyres and three sets of so-called monsoon tyres, which guarantee the necessary safety, even if the track is waterlogged by a sudden downpour.

Bridgestone will produce about 60,000 tyres for their teams this year, and bring 1,200 tyres to the track for every grand prix.

Choosing the right tyres is an art in itself. Picking the wrong type can ruin a driver's chances completely. During free practice, they have to find out which tyre compound is required on a particular track, and which best suits the car.

In contrast to everyday traffic, the tyres in Formula 1 are subjected to extreme pressure. The cars accelerate from 0 to 100km/h in 2.6 seconds. The rear tyres have to give the 700HP car enough grip on the tarmac to ensure the wheels do not spin when accelerating.

The front tyres, on the other hand, do all the hard work during braking. Statistically, given full braking from 200km/h, a Formula 1 car comes to rest within 55 metres, and the resulting braking forces apply a staggering 2.5 tonnes to the tyres in a longitudinal direction.

The load is even higher in corners, where the tyres have to withstand lateral acceleration forces equivalent to about 2.2 tonnes with centrifugal forces of up to 3.2G.

Downforce

Even when driving in a straight line, unbelievable forces are applied to the tyres by the downforce generated by the wings. When racing at 320km/h, the wings press the car down with a load of 1.6 tonnes at the rear and 1.1 tonnes at the front.

The downforce from the wings is so great that, in theory, a Formula 1 car, with a medium wing setting could drive upside down on the ceiling at a speed above just 150km/h.

The rubber compound of a Formula 1 tyre works optimally in a range from 70 to 95°C. If the tyres are cooler, they cannot develop enough grip and if they become hotter, they wear out too quickly.

In the worst-case scenario, they develop blisters, which could lead to the tyre bursting. To prevent that, the tyres are subjected to strict quality checks at the factory.

It was also a novelty in Formula 1 history when Michelin advised its teams during the 2005 USA GP to withdraw from the start for safety reasons. With just six cars, the race was disappointing for viewers in sporting terms, but also proof that the motto "safety first" stands above all other interests in Formula 1.

The 2006 USA GP will be held on Sunday in Indianapolis.