tyre side walls

[e gaines]

why are tyre side walls taller on a f1 car, then champcar lemans cars

[manchild]

why are tyre side walls taller on a f1 car, then champcar lemans cars

Because of FIA regulations which limit rim diameter on 13 inches.

12.4.4 Wheel bead diameter must lie between 328 and 332mm

[e gaines]

thanks Manchild, but because its a rule is there a saftey reason why they run tall side walls,or just because its a rule.

[manchild]

Actually I think its because of the safety but nothing related to tall side walls but to diameter of brake discs. If wheel bead would be bigger than brake discs would be much bigger and threfore brakes much more efficient which leads to higher top speeds and later braking which is obviously more dangerous than having less efficent brakes, lower top speeds and sooner braking as it is nowdays.

[e gaines]

once again thanks,i knew to post here. for the right answer

[Rob W]

Not to mention the sidewalls act as a major part of the 'suspension' of the car. With lower sidewalls they'd need more suspension travel.

FYI, I only said this because I heard Martin Brindle answer the same question once.

Rob W