A track buddy is running 19 inch wheels on his turbo and wants to try slicks. His wheels are 8.5" Front and 11" Rear. He has a JRZ suspension so he has enough stiffness to use them. he asked about sizes that fit because other guys have had issues with ABS due to too large a difference in rolling diameter front to rear. Anyone tried this? BTW, as far as I know, you are not supposed to run 19 inch wheels on a 996TT but, that's what he bought!

Thanks

 

U can run any diameter you want as long as the circumference of all 4 tires is the same or at leats within 3%, the problem is not with the ABS, the problem will be the 4wd system. If the front tires have a smaller circumference they will spin faster than the rears and melt the front diff.
hope it helps

 

HIs question was whether he could run the same tires as the 997.1 GT3. Damned if I know

By the way too big a diameter difference does mess up ABS too.

 

there are so many 996TTs out there running 235/35/19 fronts and 315/25/19 rears it's not even funny.

That is the safe size to go with.

 

Hi Bob-

No issues with those GT3 sizes, I don't know what size slick / brand choices he'll have, however. I run (and have for some time) slicks on the 996 TT in 18 and have too few choices for my liking. Who knows... maybe he'll have more options with 19.

HD

 

I have the manual for my 2005 Turbo S. 18-inch wheels were standard and Porsche says 19-inchers are optional. As long as the tires meet requirements, the bigger wheels are OK.

 

I just ordered 235 35 19s and 325 25 19s PS2s. Not too many tire choices. I did not see any slicks in that size during my search.

 

Sorry, meant 315 25 19 in the back. 25.2 rolling circumference verus 25 on stock 18 tires.