[jamesb]

Seems like the majority of drivers in the regular GT500 forums are dragsters and want big phat tires, but I'm interested in road racing. I see the shelby terlingua car with 20" razors and skinny tires. Porsches seem to go for skinny little tires too.

I understand that 18" wheels have less rotational inertia than 20" wheels, assuming they have same weight. Another issue is tire availability - 18" has the best availability, but corvettes have 19" so there are more racing tires available now. Thicker tires are good for hooking. Are thinner tires better for cornering? What are the issues?

Be grateful for your opinions on the matter, and any links explaining the engineering/physics/experience behind the various options.

Thanks!

James

[joetroberts]

jamesb, on Jul 9 2009, 02:11 PM, said:

Seems like the majority of drivers in the regular GT500 forums are dragsters and want big phat tires, but I'm interested in road racing. I see the shelby terlingua car with 20" razors and skinny tires. Porsches seem to go for skinny little tires too.

I understand that 18" wheels have less rotational inertia than 20" wheels, assuming they have same weight. Another issue is tire availability - 18" has the best availability, but corvettes have 19" so there are more racing tires available now. Thicker tires are good for hooking. Are thinner tires better for cornering? What are the issues?

Be grateful for your opinions on the matter, and any links explaining the engineering/physics/experience behind the various options.

Thanks!

James

I run PDX event on the east coast with my Shelby GT. My plans are to stay with 18" wheels, but to increase the width to 9 1/2" to 10" just like the ford FR500 racer. per my instructor, wider and lower is better, more tire in contact with the road the better. Griggs racing use a 10" wide tire on front & rear. Contact your local SCCA club for additional info.

good luck, you can check out my video on the form.
Joe

This post has been edited by joetroberts: 09 July 2009 - 05:25 PM