gray635

I just bought a very nice set of refinished Cup 1 wheels from a fellow Rennlister. The Dunlop Star Spec Z1s that came on the wheels are good for a few thousand more miles but I'm starting to think about replacements.

Current sizes are: 235/40/17 front and 265/40/17 rear. Are these the preferred tire sizes for these wheels or does the board have other suggestions? Thanks for any help!

Vandit

Cup 1s come in widths from 7-9", what's the width on your set?

Jaye Bass

235 sounds like a lot of tire for 7" wheel width.

Earlydays

The factory spec is 205/50 and 255/40 for 17"; though lots of people run 225/45 on the front.

TrackdayRSA.

Are you looking for tires for road or track use?

gray635

Chris:

Street - no track. While I would be interested in any suggestions regarding tires, my real question goes to the optimum size.

Rears are 9". Can't read width and offset on the fronts due to refinish/powercoat and don't feel like pulling a wheel to confirm but I'm pretty sure they are 8".

BGLeduc

This has been discussed on Rennlist ad nauseum.

If they are replicas, the fronts may be 7 1/2. My road wheels are 17" Mille Miglia Cup 1 replicas which came in 7 1/2 and 9. That is based on what came on the Carrera RS.

As Earlydays said, 205/255 are the factory recommendations for those size wheels on a non-turbo, narrow body C2. I run those on the street, and even with a 7mm front spacer, I still get a little rubbing at full lock on the inner wheel well.

If you are not going to track the car, there is no reason to go beyond 205/255, as that is what Porsche considers "optimum".

FYI, there is a Porsche Tech Service Bulletin #4440. The one I have is dated 5/2003. That is where I found the preceding information. All the approved fitments for all 964's are covered; turbo and non-turbo.

Brian

gray635

Guys:

Thanks for the good info.

HalV

I run 225/45s on the front and 255/40s on the rear. My Cup 1s are OEM 7"F and 9"R widths.

Opo

+1 ^^^^^^^^^^

gray635

^^^^^ That's the way I was leaning. Many thanks for the confirmation! My friends at the Tire Rack will be glad to hear from me again.

tokoro

can i use 275/40-17 for turbo look? is it better that is wider?

Slow RSA

I know you're talking about doing a street tire, but my car allows for 245/17 front, 275/17 rear using 8" front wheels (formerly on the rear of my car) and 9" turbo wheels on the rear. Tires are Hoosier R6, and i use a small spacer in the rear (6mm or so). You may need to roll your fenders/quarters, though.

tokoro

just what i wanted to know!!!
best regards