GreekPT

I'm leaning towards the RA's on a set of SSR Comp H wheels for HPDE use since they can be left on and driven to the track - as long as it's NOT raining. I was reading some other threads about how it's important to keep your F and R diameters equal or real close to it so AH will work properly.

The RA's front 275/40-17 is 25.7" diam and rear 305/35-18's are 26.4" diam which equals a 2.7% difference/bigger in rear. Will that cause problems? I'm not new to HPDE's but new to the Z06 and I'll be driving with Comp Mode ON.

My first two track days had the rear busting loose and the front sticking quite well so I don't really want to go to 17" rears even though they are way less expensive.

Thoughts??

Thanks,
Phil

freefall

I have no issues running those sizes.

mountainbiker2

I run those tires and have no problems. I run with AH/TC off.

Steve

98Pace6sp

I have the same tires; no issues and I drive on the street with them all the time.

Bob 33

The suggested size of RA1s will work fine on street or track. Except for the low wear rating, they are the best cross-over tires. Why the concern with rain? If they still have some tread, they should be ok in the wet. If going with RA1s, you wont find suitable size 17" rears, so you will be going with either 17/18 or 18/18.

Bob 33

emf

Phil - AFAIK, there needs to be less than a 3.5% delta front to rear, for AH/TC to keep somewhat happy. I've run about a 7-8% delta, and it's annoyed the computers significantly, but not to the point where it caused undo issue.

OTOH, if you don't use the computers, it doesn't really matter.