What is the minimum advised wheel width to run a 245/305 sticky street tire? There is a set of used Forgelines locally but I believe they may be 8.5 fronts and only 11 or 11.5 rears for some reason. They were off a 997.1 GT3 with old rain H20 Hoosiers on them. I'm thinking about picking them up as a second set of track wheels to run street tires and drive to the track on when i don't want to deal with transporting my Pirelli DH set.

Will a 11.5 cut it for a 305 or are these too narrow?

 

These are 305's on my 11.5 Champion Motorsport rears. The rears on my avatar pic are 11's. Both look fine to me.

Some have indicated that the factory 12's stretch out the sidewall noticeably depending on the tire brand,

 

Thanks, that fitment looks ok. The tire is a little bit wide but nothing crazy. Do you notice any slop in the rear end when cornering hard?

 

For street wheels, those widths are fine.
For track wheels, no.
I would run at least the OEM width on the track

 

I think they will be fine for street or track. I have a set of 8.5 and 11 wheels that i mounted Michelin pilot super sports for use as a true street tire. The Michelin only comes in a max with of 295, so I have 245 and 295 widths. It's fine. It definitely has more tendency towards over steer, but I usually back off the rear sway bar setting when those wheels are on. I was lazy and left them on for a local autocross, and still was 3rd on index, out of probably 80 people. I haven't tracked on them, but I definitely would if I needed to for some reason. I don't think an average driver can tell the difference between an 11.5 and a 12, in fact none of the 200 treadwear tires I'm familiar with suggest going up to a 12" wheel. Everything maxes out at 11.5, so technically the 305 is stretched on a 12" wheel. I think the over stretch is part of why I never really liked the RE71r on this car.

To the OP: if you go to tirerack.com and find tires by brand, you can see all the specs of each tire you're considering. You can find the true measured dimensions, and what width wheel they were measured on. You can actually search around and see which brands run a little wide or narrow. I don't think you will see any tires on there that will say you actually need a 12" wheel to meet manufacturer recommendations.

 

Zero slop when cornering. Here is a 11x19 with a brand new 305/30R19

I use a 10mm spacer with these. My GT3 is street only, no track or auto-x, those days were back in the '80's in a 911E and a Formula Vee

 

95% of the 996gt3 track crowd run 305/315 rear tires on 11" wide rear wheels. Never heard a problem on that side, not sure why these wouldn't be better.

 

Thanks guys what about the 245 on a 8.5?

 

You make a good point, there aren't many 305/18 street tires. Most only go up to 295. Wonder if it's better to run a 235 front to balance out a 295.

 

I think you could go either way, and it really depends on the tire. The pilot super sports i have don't seem to have any adverse effects of running a 245 on an 8.5" wheel. But if you're looking at the Yokohama 200 tw I'd probably be shopping for a 225 front, because they run a little big and they do NOT want to be pinched on the wheel, at all. Fast time trials guys are running the yok 225 on a 9" wheel. If you end up with a little too much grip, its easy to bring in a little more sway bar to balance out the car. I've been trying different tire and sway bar combinations on this car for 2 seasons now, and I find that there's always something new to learn.

Best bet is to research the tires you are considering, and see if the specific model of tire works best with narrow or wide wheels.

 

No problem at all Cosmos. Have tracked 255 NT01 on a 8.5 for years with no adverse effects. Again, 245/305 is the most widely used track tire size on a 996gt3 and they are stock 8.5/11" wheels.

You are good to go!

 

Wow never heard of anyone using a 225 on the front of a GT3. I thought the fast guys try and cram as much tire on the front, up to a 275. I wouldn't think that it's possible to have too much grip on a 225 front. I can notice a lack of grip even going from a 245 down to a 235 on the Pirelli DH.

 

^^225 on a 9" wheel

^225 on a 9" wheel

^^left 225 BFG on a 9" wheel - right 205 yok on a 9" wheel

^^Outer edge wear on a yokohama after only 45 autocross runs.

If you are trying to make the best out of a streetable alignment, you need to keep those outer edges supported with the wheel. My car only has about 2.7 degrees of front camber because I put several thousand street miles on every year. So I haven't found the benefit of putting huge tires on a small wheel, at least partially because I'm not willing to put a track only alignment on the car.

 

Those yokos aren't known for durability. I'm running -4 front and -3.2 rear so plenty of camber and I rarely drive my car on the street.

What wheel is that by the way? Looks great

 

I honestly don't know about the wheels, those are pictures I captured from an SCCA forum. I agree with -4 camber in the front you don't have much motivation to keep the tires small.... other than the fact that you might not be able to find larger than 295 for the rear. I probably wouldn't try to stuff 265s on the front and end up with 265/295. I doubt you'd have any trouble with a 245