Protocav

Has anyone ever run the 245/325 combo on the narrowbody, Non-RS GT3? I am not worried about the widths, but more concerned about the larger diameter. I expect a slight increase in grip, but wonder about any disadvantages...???

Any thoughts?

ghst868

I'm currently running 245/325 on my 997.2 GT3. So far I have had no rubbing or any other issues.
The speedometer will read slightly lower (1.8%) and the diameter ratio is somewhere around 0.97 which is still within the acceptable range.

Some people say that running this set up on NB, increases understeer. However, I haven't experienced any of that, I would say this set up has improved the handling of the car ( I went from 235/305 Michelin SS to 245/325 Michelin SC).

paver

I went to a 245/40/18 NT01 and it does rub. According to manufacturer spec's this tire is only .05" diameter greater than a stock size MPSS.

Protocav

I wonder if the increase in grip was more from the tire compound?

That's good info, my car is lowered 7mm as well so that could be an issue.

ghst868

Most likely. I would say with the 245/325 set up the car is still balanced.

My car is also slightly lowered but I don't rub. I think its because I run 2.5 degrees of camber front and rear.

mdrums

You rub where?...liner or fender edge? If it's just the liner and you have adjustable thrust bushing in your lower control arms that is a easy fix on the next alignment.

paver

where the green arrow is and also very slightly at the top of the wheel arch

Protocav

looks like you might have the front RS wheel as well...no?

Serge944

Run the 245 front only. Why put a taller, heavier 325 on the drive wheels?

pvdw

Staying in right ratio, added rake, larger tyre with more grip
TO OP : Posted a thread on 245/325 tyres on NB recently

Very happy with results so far

Mvez

Just mounted my 305-35-18 NT01's, and they are perfect. Same width as old 335-30-18 RA1, but slightly taller.

The NT01 245/305 combo is now THE tire combo to run for all 997 GT3's, including both gen RS's.

paver

Actually the wheel in the pic is stock(narrow body). The one that rubbed was NT01 on OZ challenge 8.5x18. The offset on the OZ is 50(i believe) vs 53 for stock, so Im not sure how much that matters. My camber in front is -2.5.

Protocav

Do you have a pic of that fitment, by chance?

Thank you all for the responses.

Mvez

I'll try to snap one this evening, I just had them mounted up. They fit virtually identical to my 245/305 RA1's on 9"/12" CCW wheels (RS fitment), -3F/-2R camber.

My 245 RA1's always slightly rubbed the liner at full lock, no difference now, but I don't care about that, doesn't affect anything.

997gt3north

Official Spec Tires


Stage 1 (Arrive & Drive - Spec)
245/35/19, 325/30/19 MPSS

Stage 1b (Arrive & Drive - Gold)
245/35/19, 325/30/19 Trofeo R


Stage 2 (DE Cup - Spec)
245/35/18, 305/30/18 - NT01s

Stage 2b (DE Cup - Gold)
255/35/18, 335/30,18 - R6s

Stage 2c (DE Cup - Platinum)
265/35/19, 345/30/19 - R6s


Stage 3 (DE Cheater - Spec)
24 / 28 - Michelin Slicks

Stage 3b (DE Cheater - Gold)
25 / 30 - Michelin Slicks


Stage 4 (DE Insanity - Wide body Spec)
270/330 - Michelin Slicks