What's the widest front tire that you can fit on a 997.1 NB GT3 without modifying the bodywork? I have about -4 camber in the front 8.5 caster and currently run a 245/645/18 Pirelli DH. I got some 260/660/18 Hankook C51 slicks wondering if they will fit in the front without rubbing on a 18x8.5 wheel.

 

Depends on your front wheel offset, but I routinely autocross 275/35/18 up front on OEM like wheels and aggressive autocross camber. It only rubs when close to full steering lock which really only occurs when I park and am not careful

 

The front tub and fenders are the same on a NB or WB. I run a 275/645-18 on an 18x10 without any rubbing at a front ride height of 100mm. It's on a 996 but the front wheel carriers are the same as on a 7.1GT3. I would imagine 997 fenders are basically identical to 996 ones. I use steering angle limiters on the steering rack to prevent rubbing on the inside at full lock.

 

Here are my wheel specs. I don't have any issues with 245/645/18 but the 260/660/18 is taller and wider so it may not fit well on the narrow wheel and may hit the fender/suspension. I do have a lot of negative camber in the front so that should help.

OZ Racing Challenge front wheels 18x8.5 ET50
OZ Racing Challenge rear wheels 18x12 ET63

 

The widest you can go on a 8.5 wheel is a 245 at best. A 245 should use a 9. Fitting a wide tire on a skinny wheel never works. The only way to do it right is to get a proper width and offset wheel.

 

Yep I was running a 245 on a 9 wheel but cracked a CCW and they were being a pain in the *** to replace it so I switched to OZ and those are only 8.5. I guess i'll stick with the 245, haven't had any issues so far.

 

Adding some experience running both 245 and 265 Pirelli DH slicks on 997.2 GT3 NB. (OZ Wheels 18 x 9 , 18 x 12 ) For the rears both 305 and 315’s, as you should look for proper balance front to rear..therefore ran 245 F 305 R. Then two sets of 265 F 315 R.

Observations, better turn in grip, better braking and faster track times with wider tires, My first set of 265’s they fit perfectly with no rubbing at all.. now for the mystery, the second set of identical tires rubbed in hard cornering on the inside fender.. I swapped them side to side to see if anything would change, but again they rubbed in both sides of the car. The rubbing was eating into the inner fender liner. Even spoke to the Pirelli tire engineers who couldn’t explain the mystery of the same size tires being different sizes. other than raising my ride height.

Ive gone back to the 245/305 set up, which works perfectly with likely less stress on the car..

hope this helps

 

Thanks this info is very helpful. What was the 265 size, 265/645? I picked up the a set of 260/660/18 and 300/680/18's, that's going to lean towards a lot more oversteer but it's worth an experiment. I hope it doesn't rub once mounted.

 

Should have included the complete tire size for you..
front 265 645 18
Rear 315 680 18

be careful of tire height front and rear,

I’ve switched back to 245 645 18, 305 680 18.. zero rubbing,

good luck.

 

No worries, I could see a 265/645 fitting, I think the 660 is going to be too tall but we'll see. 245/305 is a pretty common known size. I prefer the 680 rear to the 660, more effective sidewall and more forgiving.