As the title says, I would like to know if it’s possible to run 315/35 ZR 20’s all around on a 957 Cayenne Turbo with the Brembo GT 405 mm brake upgrade in the fronts. Based on the search I have done, it looks like 275/40-20 front and 315/35-20 rear tire combo has been used, but I would rather have 315/35’s all around.

Is it possible to run 20x11 wheels with 315/35-20’s all around without having the front tires rub against the inner front fenders during full turn?

I can have custom fender flares done in 6 to 8 cm. Would the fronts and rears work without rubbing with 30, 35 or 40 offset and fender flares? How much would they stick out?

I can tell you that a 295-35-21 on a stock gts wheel rubs the inner fender @ loading level and full lock. There is a ton of traction here but not so much that when it finally lets go your too far gone. I've had the CTT drifting at well over 100 and its a very predictable ride.

After doing some high speed turns with PCM on and off, I think the first reaction of the 957 CTT is to understeer. Then, you could turn that into a nice controllable oversteer by feathering the gas (after you get the front back into facing the apex).

I have 275/40 - 20 tires on all corners. So I would like to bypass the 295/40 - 20 option and jump directly to 315/35 - 20 option.

What I'm trying to figure out is how much offset I would need to make 20x11 wheels with 315/35's work in the front and rear? 30, 35 or 40? Anybody running 315/35's?

I'm very close to pulling the trigger on a set of 20x10.5 wheels in 40 offset with 315/35 - 20 tires all around.

Do you think 40 offset all around would work without any rubbing problems, especially the fronts during full turn?

Which wheels are you considering? Be sure to verify that they will clear the brake calipers in front.

I'm getting pricing from couple manufacturers. I think I have the offsets figured out and I believe 20" wheels will clear the Brembo GT 405 mm Big Brake Kit. I remember seeing a thread here about a 957 CTT with Brembo GT 405 mm Front and 380 mm Rear Big Brake upgrade. I don't remember what size wheels were on that car. Maybe somebody with big brake upgrade can chime in.

Can't wait to see the end result. What wheels you going with? Just got to be careful of the dish of the rim. Have the manufacturer and/or retailer guarantee that they will clear your brake calipers.

Why the 315 35 20? I would go with a 295 40 20 on a 20x11 fwiw...

The reason for choosing 315/35 - 20's over 295/40 - 20's is simply due to having not many performance tire options in 295/40 - 20 size. In the 295 size you are basically limited to Pirelli P Zero Rosso or Yokohama Advan Sport as performance tires and I'm not a fan of both these tires.

Also, having 315's all around on a 4x4 500-700 HP SUV will minimize the understeer and make the 2.5 ton SUV handle like a go-cart in dry and wet conditions.

I'm still talking with the wheel manufacturer. Not easy to get oversized parts over 10,000 miles.

Based on this diagram, the 20" wheels should clear the Brembo GT 405 mm Big Brake calipers.

I'm not good at posting pictures. So here is the link.

http://www.racetechnologies.com/imag...32E57FF864.pdf

I'd be very careful assuming the 405 Brembo package will clear 20" wheels. Most wheel "barrels" will taper smaller to the outer edge of the rim and cause interference with the calipers. I'd suggest you contact Brembo directly (their US distributor is in California) and see what they tell you. Either that or provide your wheel manufacturer with the Brembo drawing and obtain a written representation that the 20" wheel they produce will fit or you're not responsible for paying. Can't wait to see the outcome.

I have the caliper cross section diagram from Brembo USA. That's all Brembo can provide me. I know what you are talking about the wheels tapering or making an indent at the outer edge but I think I should be ok. Getting a written representation from the wheel provider for a wheel that is going to be mounted on a car 10,000 miles away is impossible.

As far as I know, the Ceramic Brakes offered on 957 and 958 Cayenne Turbo and Turbo S are larger than 400 mm. Do they clear 20" wheels? Anybody with Ceramic Brakes on 20" wheels?

They are 410mm at the front on the 958 Turbo, and Porsche says that you need a minimum of a 20" wheel to clear them.

That's exactly what I'm saying. 20" wheels should clear the Brembo GT 405 mm brake kit.

Looking at the Brembo diagram, the calipers have 231.4 mm radius. That's 46.28 cm diameter, which is 18.22 in. Basically on a 20" wheel, the Brembo GT 405 mm caliper will yield approx 0.89 in between the caliper and the inner wheel. It would be a tight fit but it should work, especially on 1 piece 20" wheels.

Hopefully, in couple weeks I would have pictures of this tight setup.

Should be awesome. Looking forward to pictures. HRE supplying the wheels?

My fingers are crossed for you, especially being that far from the wheel provider. The rear shouldn't be an issue, but the front's offset needs to be SPOT ON to clear that caliper. Can't wait for pics, you'd better post them up!