GHSilver01

I just bought a 2001 996tt and want to change the wheels from the 18" turbo twists to a larger wheel (19 or 20). My local tire guy says a larger wheel may hurt the AWD setup even if I stay as close as possible to the stock outside tire diameter - is any of that true ?

nzskater

No, it will be fine.

tguaturbo

I had a 996tt with 19" HRE's. I think the rear series needs to go to a 25 instead of 30. That may have been because I went a tad bit wider than stock. If memory serves me right the rear was a 315/25/19 and front was 235/30/19. In any case all I was told was to make sure the rolling diameter was as closet to the stock as possible to avoid issues with the front or rear differentials.

dprantl

This is the 997TT forum BTW. While differing tire diameters front/rear don't make much difference on a 997TT, they do make a difference on a 996TT due to the more rudimentary AWD system used on the 996TT. You want the diameter of the front wheel/tire combo to be slightly *larger* than the rear wheel/tire combo. This means that the rear wheels will be providing power to the front wheels. In the reverse case, the front wheels will be dragging the rear wheels down. If you can stick to the correct ratios, the AWD system should be fine. In my former 996TT I ran 315/25-19 and 235/30-19 which was close enough and worked fine. When I first got the car, it had 305/30-19 and 235/30-19 which was sub-optimal.

Dan

pfbz

Quoting this because it bears repeating... The "close to stock diameter ratio" really isn't quite right with the 996 turbo. You really need to follow the advice above.

18" vs 19" wheels, assuming correct tire diameters and wheel offsets, then becomes a matter of preference. Many feel the 18" has a notably better feel on the 996 Turbos than 19", but you'll find plenty of others that disagree...

( More 996 Turbo advice in the 997 Turbo forum)

MIKe30

atcbi5

thxbuff2001

I use soap and water.