What did they change on the GT3 to allow 11" width rear wheels?

I know the widebodies come from the factory with 11" rear wheels (and the TT and C4S have 295 rear tires), whereas the narrowbodies with 18's have 10" rear wheels and have 285 width rear tires. The GT3 comes with the 11" wide rear wheels, and 295 width tires. What exactly did they do that will allow those to fit there? Can I fit the wider rear wheel on my C2 without major modification?

I found that with my 18" by 10" BBS wheels and 285/30-18 tires, I still have plenty of room left. I run 15mm spacers to bring the wheels out to the edge so it wouldn't surprise me if you could just bolt on 18 by 11" and 295s without doing anything.

From what I have heard, the factory had to roll the fenders.

I don't believe any rolling went on. I looked at a new GT3 this past weekend and the inner roll of the rear fender still had that same 90 degree bend and lip. I'm telling you, there's tons of room as long as you get the offset right on the wheels. I've also seen 996TT wheels and tires on a narrow-body 996 with no spacers.

From the GT3 Summer Tires and Wheels TSB -- dated 3-28-03 The key here is the offset of the wheels!

Nice, I was looking for something a little wider in the back. I was just hoping to avoid using spacers, and it sounds feasible.

Thanks for the specifications there Loren. Do you happen to know what the offset for the 18" wheels on the C2 are? I can't find that anywhere in the search archives.

FWIW, the 11" rear wheels with the 63 mm offset will fit a narrow body 996 without modifications. Porsche offers the Sport Techno wheel in this size as an option.

18" Carrera Wheel: 8" x 18" - ET50 10" x 18" - ET65 18" Turbo Look II Wheels: 8" x 18" - ET50 10" x 18" - ET65 18" Sport Classic Wheels: 8" x 18" - ET52 10" x 18" - ET65 18" Sport Design Wheels: 8"x 18" - ET52 10" x 18" - ET65

stock996 turbo wheels in 11" do not fit the offset is wrong and they stick out.

Anybody know the weights on the new GT3 wheels?

For what it's worth, I race a 99 996 C2 with 11 inch rear wheels and 305/30/18 Hoosiers. The car is very low, the fenders are rolled and I have much more camber than you would use on the street but they can be made to fit. For a street application, 10.5 inch rears with 285s seem like a much better choice.

i just saw & ordered a GT3 a week ago. the fenders are infact rolled all the way around the car.

hmm...we seem to have a major amount of conflicting data here. The only thing that still leads me to believe that the fenders infact aren't rolled is that Porsche has the Techno Wheels in the exact same size and offset as the GT3 wheels as an option for the C2, C2 Cab, and C4 Cab. I doubt Porsche rolls the fenders at the factory of the cars that specifically order the Techno wheels.

I hardly think Porsche is going to roll fenders on their cars to make wheels fit.

All GT3 street cars have all 4 fenders rolled as the GT3 cup cars do. This is because of the 235/295 tire combination in conjunction with much lower ride height than stock(with ability to go approximately 10-15mm lower than delivered. The standard 996 has the front fenders rolled, but the rear(at least on all early generations) is NOT rolled. If the lip is rolled, it makes approximately a curved 30-45 degree angle in the inner/upward direction. If not rolled, it has a 90 degree angle from the outer portion of the fender with a "sharp" inside edge. Porsche likely presumes that the standard 996 (which the techno wheels can be used on) will be running at stock ride height. At a low height, and a non rolled rear fender lip, clearance with the 11 inch wheel and the 295 tire may be an issue.

Thanks Lynn for clarifying that. Right after I posted and left for work I realized that the GT3 fenders might be rolled due to the lower height than the standard 996 models. As I use the M030 suspension I don't believe there is any need to worry about an 11" wheel with the proper offset such as the Techno wheel to rub with a 295 width rear tire. Lynn, do you know why Porsche rolled the front wheel well? I don't see much of a reason with the narrow 8" wheels they stick up there. Was it because they expected people to increase the width of the front wheels/tires for the track?

The fender lips are rolled in the front because when the front wheels are turned and the car is cornering, if there was a sharp edge present, it might cause damage to the tire. If one was going around a right turn, the wheels are obviously turned to the right, and hence the outer edge of the left front tire(which has now moved out from the fender area) would come in close proximity to the fender as that fender is now lowered under the force and load of going around a corner. Even in the race car, it still often rubs because of very low ride heights on turning. Porsche designed the car with specific wheels and tire combinations. Although they know that different wheels are often used, they would not roll the fenders as a precaution for this possibility.

I see. Thank you