964RS_NGT

I asked a question about the 996 "lightweight" 5-spoke rims the other week and despite me having reservations, my friend eventually bought them cheep for track day events. Question now is tyre size...
His car is a 997.1 C2 with OEM, non-PASM sports suspension (-20 mm vs base C2 / -10 mm vs PASM cars). A proper alignment should get him close to -1/-1.5 camber front/rear.
Rims are 8x18 ET50 front and 10x18 ET65 rear. Will be using 17 mm spacers in the rear and have 5 mm avaliable for the front if needed.

Obviously there aren't that many combinations... Stock size of 235/40 and 265/40, don't think so. What do you think of 245/35 front, 275/35 rear? This gets a diameter diff under the required 4% (3.3).
I believe 996's uses 285's on 10" rims, but that will push diam diff to 4.3%, a tad too much perhaps.

Any opinions appreciated!

RonCT

Sounds like the sizes I was looking at for my Boxster at 245 up front and 275/40 (note: NOT 275/35) with a 26" rear tire diameter. Nitto makes the NT01 in 245/40 and 275/40, so that might be your best bet. Really have to question why anyone would run a 10" rear wheel on a 997 though...

My opinion has always been and remains that I am uncomfortable using a typical 25" rear diameter tire when the car and its systems are designed around 25" front and 26.3" rear. At 26.5" rear for the NT01 275/40 I believe it's close enough.

cbzzoom

C2 base model is 10" rears right ?

Check out Nugget's tire calculator :

http://macnugget.org/cars/tirecalc

245/275 should be fine on 8/10

RonCT

Well, I think the 09+ C2 comes with 10.5" rears and 265 tires, but it's a narrow body 997, which points to 11", 11.5" or even 12" rears. No need for over 11, which will take 295 or 305 rears. I always found the 245/305 combo to be a great balance. Just mounted my 2nd to last set of RA1s and wonder what I'll switch to when they are gone.