A return to the way a racing car should look, with slick racing tires, will bring new excitement and challenges to everyone in F1.
A reporter once asked 1980 World Champion Alan Jones whether his tires played an important part in his race that day. Jones replied “Oh, absolutely. You see, they keep the wheels from touching the ground.”
In the early sixties teams realized that by removing the grooves from a tire a car will have more grip on the road surface due to the expanded area of the tire making contact with the road. All teams ran with slick tires up to the 1998 season when that rule was changed. Since then teams have raced on grooved tires.
Normal road tires found on cars today has an average lifetime of about 37500 – 50000 mi. The tires found on F1 cars are designed to last less than about one race distance (188mi).
Regulations state that dry tires must have four grooves in them of at least 2.5 mm. They can also not be wider than 355 mm and 380 mm at the front and rear respectively and 660 mm in external diameter. Of course F1 tires have to be able to withstand up to 4g lateral loadings and 5g longitudinal loadings.
The three main ingredients in F1 tires are carbon, sulphur and oil. The more oil there is in a tire the softer it will be. To keep the pressure inside the tire as long as possible teams fill them with a special, nitrogen-rich air mixture, designed to minimize variations.
Intermediate tires, which can be used in slightly damp to wet track conditions must be able to function properly in a drying track to displace any water on the track but not deteriorate to quickly that would necessitate an early stop, but also be competitive enough in wet conditions.
Wet tires are used in full wet conditions with continuous rain and tires normally last longer and have the ability to displace the maximum amount of water thru the multiple grooves cut into the tire.
The harder tire is more durable but gives less grip as apposed to the softer tire that gives more grip but is less durable.
Softer tires have a painted white stripe in the second groove for the fans to differentiate on which tire a driver is currently driving. Both the hard and the soft compound must be used during a race unless wet or intermediate tires are used during the race, in which case the rule no longer applies.
In 2005 the FIA rules stipulated that tires were to last one full race distance and as a result a harder compound was used. However after several disastrous failures as well as a spectacular and dangerous tire failure by Kimi Räikkönen at the Nurburgring that year, the rules were changed to allow for tire changes.
Another reason that the rules were changed was due to the dramatic 2005 United States Grand Prix. On the Friday, Ralf Schumacher crashed heavily in Turn 13. The unusual design of turn 13, being a banked turned put a greater than usual lateral load on the tires. Michelin announced that they would not permit their teams to race on Michelin's tires because in their opinion the tires that they supplied to them were unsafe and as a result only the Bridgestone teams took part in the race.
Since the start of the 2007 Formula One season Bridgestone have been the sole manufacturers and have introduced four compounds of tire, two of which will be made available at each race.
Regulation changes for 2009 have called for a return to slick tires and a ban on the use of tire blankets to pre-heat the tires.
