427V8

So why does NASCAR use 15" wheels?
Are they just trying to slow the cars down?

Or are they better with the racing tires?

MikeC

I think the cars were just designed with 15" rubber in mind so they would have to redesign the suspension for 17" rims with low profile rubber . There probably is some regulation about tire diameter though.

SmokedTires

My "guess" is that it's probably in the rule book that 15's are used. Nascar is nothing like it was intended when they took "stock" cars installed some safty equipment and went racing, hence "stock car racing" . Now these cars are soooo regulated so one brand doesn't have a big advantage over another (ex. there is no such thing as a 2 door Taurus but they're racing them).

Also the they're racing on race compound slicks not DOT tires. The tire manufactures have alot of $$$ in the design of these new tires & are designed for this application.

The advantage of 17's is their road feel and reaction on the road. We're not driving in ovals in the real world. Many manufactures engineers are seeing the benefits of low profile tires on the street and the tire manufactures are following.