Tyres... vital role in F1 racing

The tyres in Formula One not only contribute to safety, but are now expected to play a part in reducing overall costs as well.

This season, each driver can only make us of one set of tyres for qualifying and the race - which must be employed for optimum efficiency.

"This new regulation shifts some of the responsibility from the pit back to the driver," explains Sam Michael, Technical Director at the BMW Williams F1 team.

Besides cutting down on costs, the regulation officials of the International Automobile Federation (FIA) were specifically looking to cut speeds in Formula One.

Over the past few years, lap times have continued to become faster and faster.

To secure pole position in 2004, for example, Michael Schumacher needed to be almost four seconds faster than Fernando Alonso was in 2003. The reason for this development is not as much about engines and aerodynamics as it is tyres, their substantially improved grip allowing ever-higher cornering speeds.

For now, the new regulations have halted this trend. To survive qualifying and the race, the new tyres - consisting of up to 80 different rubber compounds constructed from a selection of 220 materials - are significantly harder than before.

This results in less grip and therefore lower cornering speeds. This is a very challenging situation for the tyre manufacturers, since they now have to develop tyres that will last not only for one fast qualifying lap but also provide optimum performance over the entire distance of the race.

However, the properties of the tyre are not the only defining factor in terms of wear. The layout and the track surface of the circuit, the temperature of the asphalt, the adjustment options of the car and, of course, the driving style of the individual driver all play important roles... it's an equation with a lot of unknown variables.

Where pressure is concerned, deviations as slight as 0.05 bar are enough to decisively alter a tyre's behaviour. To maintain the pressure at a constant level, even under the most extreme strain, the tyres are not filled with air but with nitrogen.

"In ordinary road traffic, there are also many good reasons to use tyres carefully," Christoph Lauterwasser of the Allianz Centre for Technology (AZT) points out.

"Regularly checking tyre pressure increases safety, reduces wear and cuts fuel consumption - and it does not cost a thing.

"Wrongly adjusted suspension or damaged tyres - due to parking on the kerb, for instance - can substantially diminish a tyre's life.

"Tyres with worn-down tread provide notably less grip on wet or snow-covered surfaces, thus significantly impairing a vehicle's handling."

Even though the drivers no longer have a full palette to choose from, deciding which tyres to use has not really become any easier.

During free practice on Friday, they will have to decide which of the two tyre specifications (soft or hard compound) will best suit the track, the car and the intended strategy.

Once that choice is made, there's no turning back: the tyres may be changed during the race only if there is an obvious defect or if the state of the tyre is judged to be dangerous - so safety still has priority.

Commissioners' role

The teams' compliance with this rule is ensured by the FIA commissioners, who will check every replaced tyre and, should it have been changed without a compelling reason, impose drastic penalties that may even include disqualification.

If a car enters the pits for a tyre change, refuelling is not permitted. Of course, all these rules are open to exceptions: the race commissioners can allow the teams to change their tyres if, for example, cars have driven over debris scattered across the track after a crash. And if it starts to rain, the teams are of course permitted to switch to wetweather tyres with no penalty.

During such a stop, the cars can even be refuelled. Thanks to the new rule, Formula One races are no longer just a series of short sprints from one tyre change to the next.

The drivers now have to be careful and tactical with their tyres - those who are not will sooner or later face serious problems.

Did you know...

¤ A Formula One car takes no more than 4.9 seconds and covers only 140 metres when accelerating from a standstill to 200 km/h.

¤ Full braking from 200 km/h to a standstill, on the other hand, takes only 1.9 seconds and takes place over a distance of only 55 metres.

¤ During these processes, the tyres have to withstand incredible forces. The same is true during cornering where, at a speed of 150 km/h for example, the tyres are subjected to up to 3.2G.