LVDell

The R6 245/315 combo is the cat's meow!

Leigh2

Dell do you run the 245/35 or the 245/40?

LVDell

I rec'd the 245/35. Less sidewall roll and better clearance inside the wheel well. The 245/40 rubs the wheel well liner more.

P.J.S.

i can feel my self being pulled in that direction...

Yargk

I feel bigger is better from race winning cars. i.e. cargraphic's car and NJ-GTs autocross car. Doesn't NJ-GT like 10s and 12s? I'm very open to your comments about this not being the right path but your statements are always confusing to me. I feel like they should always be followed by "...."

It is not a proper fit...

why? is it slower? ... ummm what's not proper about it if it only results in a once in a blue moon rub on the fender which is easily fixed (rubbing on the inside would be a different matter). Your comment about weight makes sense, but has nothing to do with fit. Furthermore, needless weight is definitely a bad thing, but I know examples of other much less powerful cars benefiting more from just another half inch of wheel width than losing 5 pounds of rotating unsprung mass. (18 pound 7.5 vs. 13 pound 7 inch rims on a 167 hp 325is autocross car so the weight added is a much larger percentage of the wheel weight than on a GT3 yet the car was considerably faster and better planted with the wider rims)

I respect someone saying "for me I think the fit is too tight and I would prefer to have less weight," that's perfectly reasonable, maybe I might even make the same decision on one of my own cars. However, comments like not worth it, no benefit, and improper fit seem a bit misleading. Especially when engineered examples seem to prove the exact opposite.

BTW I'm not trying to flame so please take my post as respectful discussion.

LVDell

Keith, we must be talking about two totally different cars then. The GT3 is not made nor designed to run a 12" wheel. The street version is a 11" wheel and IIRC the Cup is a 10.5" wheel. As far as comparing it to the auto-x setup makes no sense as they are two totally different perspectives and one I cannot comment on. Rad (NJ-GT) is a very skilled auto-x driver and give you better info so I won't speak to that but think about how much heat you have to get into the wider tire. It is much more difficult and will never allow you to get the optimal temp....thus less grip. The game on the track is all about "dialing" in your car. Going wider is not better. However, wider is relative to your start point. Further, look at the manufacturer's rec'd on what size wheel is OPTIMAL for the tire in question. Going too wide on a wheel puts you in a situation where sidewall roll comes into play. To fully exploit a contact patch you need to have the optimal wheel size. The different size tires will have the same contact patch on the same wheel so why not go with the optimal size?

I can't type anymore, it's 645am and I still need my coffee before I hit the road to VIR

ps. I set my fastest lap time in a street GT3 at VIR (2:04) with the smallest tire combo on my 9"/11" wheels. The tires I ran were 230/650 Front 280/650 rear

Yargk

Have fun at VIR

LVDell

Thanks Keith. Have a great weekend

BTW, Did my rambling non-caffeine post make any sense?

KOAN

FWIW, CCW is recommending 9"/12" for GT3s. My guess is they make more wheels for GT3s than most other companies, and the price difference is minimal. I wonder what their reasoning is?

AllanJ

...that's for the 7-GT3 AFAIK. For the 6-GT3 they do 9"/11" (I have two sets).

Cheers,

KOAN

I recently ordered a set for my 6GT3 and asked their advice, and they recommended 9"/12", despite my persistent questioning of it. They said it was their experience that it worked better, and offered to take them back if they didn't fit. I have plenty of room, but have yet to try all of the tire sizes mentioned here.

Leigh2

I just ordered a set of HRE C20 wheels for my 6GT3 and HRE said the widest they would recommend for the rear was 11.5. I stayed with 9/11.0 to avoid any issues even though there does appear to be lots of room for 0.5" on either side of the wheel. The offset would have to be perfect! Please report back when you get the wheels. What are you going to run for tires?

KOAN

I'll run Nitto NT 01 245/315 and and R6s 245/315...I threw on an old set of PS2s (315 in rear) and there is plenty of room on those, but I don't know how the tire brands compare in actual size.

mooty

ccw does 11", 11.5" and 12" for 996GT3.
they ask you what tires you want to run. if you want mpsc, usually you be on 295, thus 11" is optimal. if you run R888, you would be on 315 or wider, then 12" would be needed. 12" does fit without fender rolling.

Yargk

Yeah, it all makes sense. All the stuff you said is true. With race tires wider is not always optimal because you might not get enough heat into them, however I have not heard that this is an issue on the GT3 since it's so heavy. The 996 is designed for 11s, but it's also designed for 8.5s in the front, yet people find success with 9s. Race car setup is a subtle and complicated thing and there might be many reasons for choosing a particular rim size, however I don't see any solid evidence that these reasons actually apply to the 996 GT3. In general the grip vs. normal force/tire area is not linear so you do get more grip from wider tires (same reason a lighter car has more grip). So assuming it fits and none of the reasons for not doing 12s applies, to be convinced that 12 is sub optimal I'd have to see a solid example of this. ie equal cars running both. Cargraphic seems to think 9.5s and 12s are pretty optimal (they won with this setup once with a 996 gt3 and once with a 997 GT3) so that's my evidence so far. Quite possibly there is someone out there who tried 12s and got slower or didn't like the feel, but until then, I don't see any of the reasons against 12s being a proof against them in and of itself.