Foam Tire Size
 

I'm new to carpet racing and it looks like the local "fast guys" have cut about half the foam off of a new set of tires. Seems to me that it really helps the cars handling. What is a good starting size to true them down to?

I usually start mine about 59mm.

For club racing and practice I cut my tires to 57.5mm, at big races I start them at 56.5mm. You can run them down to 54.5-55mm

55mm is minimum for ROAR rules though. Depending upon your setup, running below 55.5mm may upset or even enhance the cars handling as well.

Most drivers start anywhere from 60mm down to 56.5mm (again, depending upon setup, budget and race importance). On carpet, anything above 60mm usually results in traction rolling.

for big races i true my tires down to 59mm and then run them till there at 58 and then i put a set of 59mm back on.

For club races, i just toss a new set on, and run them till 55mm or till the chunk

I start mine at 59mm for club races and then run them to about 57mm and save them for big races.