Formula One Slick Tire Temperatures, Pressures
The Shape of Bridgestone's F1 Slick Tires is Critical for Grip
Mar 27, 2009
The technology behind a Formula One race tire is amongst some of the most complex within the entire sport. Just consider for a moment what a tire has to go through. At 200 miles per hour a rear tire will change shape approximately 40 times per second, (from a circle to almost a ‘D’ shape as it flattens against the track). The days when tires were considered round black things on each corner of the car are long gone.
There are three disciplines connected to tire technology. First is the chemist who formulated the construction and type of rubber for any given race tire. Second, the tire engineer whose job it is to ensure the car’s tire performance is optimized. And finally, the race engineer whose job it is to work with the tire engineers to analyze recommended changes; the engineer must ensure that optimizing tire grip will not adversely affect other performance areas.
Tire Temperature Monitors
For many years F1 team engineers and tire engineers relied on using a tire probe to check the internal temperature of the tires after the car returned from a track session. Today a series of sophisticated sensors inside the wheels monitors the tire temperature and pressure as the car goes around a race track. This new technology gives engineers a more detailed understanding of what the tires are doing dynamically compared with the old system of relying on the retained heat when the car returned to the pits.
Trying to optimize tire performance is a very difficult business. Not only must the engineers commit to a suspension and aero package before the race, they must also anticipate the weather conditions. For instance, if the engineers decided that the race was going to be run in hot dry conditions, and it changed mid way through to cold and damp conditions, the car would loose overall performance as the race unfolded.
Tire Testing
Although Bridgestone has been the sole supplier to all F1 teams since 2007, there are still compound options available to the engineers at each race. The engineers will strive to have the best tire, suspension, and aerodynamic package for any given track session and will have tested as many tire options as possible during the winter break.
Of primary concern to the engineers is the available grip a tire will generate. This grip will be affected by any number of parameters including: the weather, driver’s style, aerodynamic down-force etc. However, adjusting the pressure and camber angle will have a significant effect on the tire’s performance.
Importance of Pressure Settings
If the tire pressure is too high, the tire will have a raised center section – causing the car to slide (less contact rubber for grip) and promoting a build up of heat in the center. If the pressures are too low, the outer edges of the tires will overheat, again causing a lack of grip.
The angle at which the wheels and tires are set is called the camber angle. If the top of a tire leans toward the car, the tire’s temperature will increase on the inner edge (a setting known as negative camber). Conversely, if the top of a tire leans away from the car (positive camber), the outer edge will get hotter. In general, the engineers will be looking to have an even temperature spread across the entire tread.
Slicks Make a Return
Back in F1 for the 2009 season are slick tires. These tires are devoid of any discernable grooves and as such ensure the maximum amount of rubber is in contact with the track for a given size. Although there are no grooves cut into the rubber, slick tires have small round holes strategically placed across their tread to enable engineers to check the available rubber depth.
Generally it is easy to predict the change in lap times from one type of tire to another. Grooved tires to slicks, for instance. But with so many changes to other parts of the cars for the 2009 season, it is hard to predict what any one parameter will do to the car's overall performance. By the end of the Australian Grand Prix on Sunday night, fans and race engineers alike will know a lot more about the performance of the tires and cars.
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