Does anyone know what is the widest front tire that will fit without rubbing?

For track wheels, I am getting CCW 18x9's on the front.

Has anyone stuffed a 275 on the front?

Hoosiers new 255/35-18 is not really a 255. I have a set on another car, and they are really 275 to 285s. They just called them 255's for road race homologation. They are wider than most of my 275 street tires.

 

I think Ruf runs a wider tire upfront. There a forum sponsor that might be able to help you out. Also Peter Lee from wheelexperts.com might be able to help you out. I would like to run a wider tire on a 19" rim in the near future. I think the car would handle much better with more width up front.

 

[quote=trompazo;2285387]Does anyone know what is the widest front tire that will fit without rubbing?

For track wheels, I am getting CCW 18x9's on the front.

Has anyone stuffed a 275 on the front?

I have CCW C10's as track wheels Front is 18 X 9.5 and I ran a 275 Hoosier R6 on the front last season. Had to roll the fender wells and there was minimal rubbing on the inner liners with sharp turns such as what you might make in the Paddock area. Caster was around 8. Camber -3.

 

What did you use to get your Camber to -3?

GT3 Cup lower control arms?

 

Yes. With the slicks for this season I've gone to a wider tire and -4.

 

Al, is that on a 996 or 997tt with stock fenders?

If you can go that wide, it kinda makes the wide CF fenders that GMG sells unnecessary.

Are you still AWD? I was told even with the Cup lower arms you are still limited on camber unless you change the diff shafts, or else they will pull out. If you are RWD, then it's irrelevant.

 

My car is a 996 and is still AWD with stock fenders. Only a couple of sessions on the car since the conversion but no problems thus far. Have not changed half shafts. The tire I have on the front now is really a little wider than ideal for a 9.5" wheel but I can't get a larger wheel under the thing. Tire is a Michelin 27/65-18. Had to use that in order for diameters to match with the 30/65 in the rear. I actually gave up a little contact patch size relative to the 335 Hoosiers but there are limited choices in the Michelins for a car like mine. I'm much heavier than a cup car and have a lot of downforce. The 30/65 looks great on my 12.5 W rear wheel.

 

Intresting thread...Anyone know what is max tyres we can fit on stock 19s wheels front and rear...May be 255 front and 315 or 325 rears for track ???

Is there suc tyre combinations...

Also those who use Hoosler for track...which model do you order and why you run them insead of Michelins Pilot CUPs or Toyos or any other brands...I heard they are mcuh cheaper then those brand and that makes sense if you use for track...

How many sessions do they last ???

 

Al, do you know what offset your wheels are in front? I'm looking at moving to a very similar setup before the next time trial season begins - 18x9.5" front wheels with 275s - albeit street tires, not hoosiers. To keep compliant with rules, i'd need to stay between the stock ET50, and ET43 max. Do you happen to know what you're running?

[quote=Al Norton;2286184]

 

[quote=itacud;2303820]Al, do you know what offset your wheels are in front? I'm looking at moving to a very similar setup before the next time trial season begins - 18x9.5" front wheels with 275s - albeit street tires, not hoosiers. To keep compliant with rules, i'd need to stay between the stock ET50, and ET43 max. Do you happen to know what you're running?

I don't know the numbers. Call John at CCW and he can tell you. It should be fresh in his mind bc I just ordered another set of C10's with shiny black anodizing.
I did back down from the 12.5 rear to a 12 not wanting to spend tha additional $ for the cutting and welding that is necessary to produce a 12.5.

 

Still looking for the answer to what size will fit upfront and rear with stock wheel size. I want to order some PS2's hoping someone would know. Thanks

 

You can very safely use a 235/40/18 in front and a 315/30/18 in rear - which are a matching (diameter) set availabe in PS2 Porsche specific N fitment. I haven't actually found a performance improvement on track, however, from using this over the 225/40/18 , 295/30/18 stock sizes due to softer sidewalls. But the extra sidewall of the larger sizes has it's advantages on the street when used with a stiffer suspension. Although a 245/40/18 does fit on the stock 8" front rim, the rear tire of matching diameter, a 335/30/18, is technically too wide for an 11" stock rear wheel. If you're not still using AWD, that won't matter.
http://www.tirerack.com/tires/Spec.j...3YR8SPORTPS2N2

 

Thanks Al, I'll give them a call.

[quote=Al Norton;2303871]

 

Let's be very clear here that you are talking fitments only for a 996. You CANNOT use matching diameter tires on ANY 997, RWD or AWD.

 

I apologize... I just realized the question was asked about a 997. Yes, my answer was 996 specific. Still, it's easy to answer the question of what size PS2 fits a stock wheel - it should be printed on that spec page I included.