user 783003

I'd like to move to a slick next season for AutoCross (PCA and SCCA). Looking at TireRack's site, I don't see Hoosier A's in my sizes.

I'm running 205/50-17 in the front and 255/40-17 in the back.

Hoosier has these sizes:
225/40Z-17
225/45Z-17
245/40Z-17
275/40Z-17
295/35Z-17
315/35Z-17
335/35Z-17

Will any of these work on my 7" and 9" rims?

race911

I used to run 225s and 245s on 8 and 9" Cup 1s when racing RSA #1. I just squeezed some old 245s on 7.5 Cup 1 replicas for duty on the yellow 993, so I know they will fit. Not optimal, of course, but sometimes you work with what you've got laying around. Just look at the spec sheet for mounted dimensions and rim sizing.

2002M3Drew

You can run the 225/45/17 and 245/40/17 sizes. The 245 is going to be too much of a squeeze on the 7's. You might get them on to the 7's with a patient and strong tire guy, but they won't sit right, and you'll defeat the purpose of the larger rubber while adding weight. The 275/40 is too much tire and too much stagger for the rear. The 225/245 combo should give you a nice balance (I run those sizes in 16" on my SC).

If you are not set on Hoosiers, you could see if there are some better sizes available in the V710 Kumho. EDIT: Just checked, and the 17" Kumho options are the same, unfortunately.

Earlydays

BFG R1's are available in 225/45 -255/40.
Another thing you might consider is running in a street tire class in the SCCA and also sticking with street tires in PCA and using one of the "hot" street tires like Bridgestone R11's or Yokohama AD08's. I run the Yokohamas and love them, they're not Hoosier A6's, but surprisingly close. I ran "R" tires for 10 years, both Hoosier's and Kumho's and I find the the AD08's to be outstanding and I don't have to haul/change wheels and tires for the events.