if low profile tires handle better why are they not used on Formula 1 or IRL or Champ or Nascar?

Question

High performance street cars all are equiped with low profile tires for better handling, however, all of the major race series' run on tires with rather tall side walls. Does anyone know the reason for this. If you look at the road holding ability of the greatest street cars ever made, none of them even come close to a Formula 1 car. I understand there is a huge weight and aerodynamics difference, but the tires in Formula 1 must be the result of more R & D than any other tire in the world. Thanks

Answer 1

The main reason are rules - plain and simple. Formula 1 has a rule that states wheel diameter is 13". Using a larger diameter would result in being disqaulified, so 13" wheels are used. The wheel limit sizes are largely there as an effort to control speed, since this places some major restrictions on brake size.

Through from a performance perspective, larger wheels are not always better. While a 17" wheel may offer more rigidity and allow for larger brakes than a 16" wheel, an 18" wheel on the same car could actually decrease performance. Wheels tend to weigh more than the tire, so going with ever increasing wheel sizes mean that you are constantly increasing unsprung rotating mass. So maximizing performance becomes a tradeoff of balancing the gains in contact patch and grip, against peformance loss for the gained weight and added momentum of the rotating mass.

On a race car you deal with very lightweight wheels and tires that have very stiff carcasses that are placed on car that range from ultra-light to very light overall weight. On a street car, performance considerations include tire noise and comfort as well as grip, and cost considerations are more prominent. Wheels must be able to withstand things like potholes and will be heavier. The cars on which they are mount are MUCH heavier than their race counterparts. With so much more weight involved, the ratio differences in sprung verses unsprung weight are less sensitive to increases in unsprung weight (meaning that you have to increase more to dramactically effect the ratio), so the potential gains in grip may allow for larger practical sizes than you would want on a similar car if you were racing (though the size that would work best is still probably going to be larger than the rules will allow).

Answer 2

Areas to think about. Presently an increase in tire pressure changes the coil spring rate. It actually make the suspension "think" it has a slightly stiffer spring. The opposite if there is a decrease in nitrogen pressure in the tires. NASCAR and all other types of racing designates wheel size. For instance the NASCAR wheels are 9.5 inches wide with a 5 inch bolt circle. That rule has been carved in stone since hector was a pup. If someone were to change tire section dimensions the cars would drag on the ground. I'm sure Goodyear would not want to open a can of worms. Low profile tires do not dissipate heat well. In racing conditions they'd blister and blow out.

Answer 3

Heat is the name of the game in racing. There is heat from the brakes and heat from the tires contacting the racing surface. The sidewall allows the heat to dissipate somewhat. Also, the teams want some flex to the sidewall. It keeps the car from becoming too tight in the corners.

Answer 4

Name one so called high performance street car that can match an F1's performance.

Answer 5

Inner safety tire , blowout's tend to hurt at 180 mph