[SCRAPPYDO]

Okay, aside from weight and cost of tires, is there any reason why 18" rims/tires would be inherently bad for autocross. Assuming I am fine with buying new 18's often, I cant see any reason why the reduced sidewall would hurt. Less tire squirm is a good thing (up to a point)

Just asking. I have had great luck autocrossing my RE070's, but I recently bought new rims 18x8.5 and will either run RE01's or RT-615's on them in a 235/40/18.

The overall package is 1-2 lbs lighter per corner than my OEM set up.

[thunderbird]

simple answer, no. It seems bigger tires are better for autocross. I think its about the energy that gets absorbed into the surface. the more surface area, the cooler the tire stays. I think the biggest limitation on our cars is the size of tires we can put on. I just put 265/35R18s on 18x9 rim. C4 corvettes have three or four inches inches of clearance and I'll be lucky to get an inch of clearance. Some people successfully put 275/35R17s on the stock rim on '05+ cars and stock suspension. You can easily put a 245 wide tire on the stock rim and the STU class allows up to 245 widths.

It will be hard to do better than the RE070s though for tires.