[Citrusbb]

Will the use of 35 profile tires instead of 30 series cause a computer problem on a 2020 2SS 1LE? If so, is it an easy fix by GM?

[arpad_m]

No, it works even on a non-1LE SS, I have that exact configuration (285/35/20 front, 305/35/20 rear) by somewhat of a coincidence. Everything is fine with the ECM/TCM, and the setup looks awesome.

Clearancewise, however, you'll be cutting it very-very close: there is some slight rubbing in the front at full left lock, and unless gm changed main body wiring harness routing for 2020, you will need to relocate this harness in the driver side rear wheel well to avoid constant rubbing in the rear (see this thread: https://www.camaro6.com/forums/showthread.php?t=485975).

[Citrusbb]

Originally Posted by arpad_m

No, it works even on a non-1LE SS, I have that exact configuration (285/35/20 front, 305/35/20 rear) by somewhat of a coincidence. Everything is fine with the ECM/TCM, and the setup looks awesome.

Clearancewise, however, you'll be cutting it very-very close: there is some slight rubbing in the front at full left lock, and unless gm changed main body wiring harness routing for 2020, you will need to relocate this harness in the driver side rear wheel well to avoid constant rubbing in the rear (see this thread: https://www.camaro6.com/forums/showthread.php?t=485975).

Thanks! I really like having a little more rubber between the wheel and the road. My 2015 1LE had 35 series, and I don’t understand why GM decided that 30 was better. Your answer really helps, thanks much. Maybe we’ll meet one day at a track near you.

[BrandanK]

For what it is worth, I have heard that the Michelins tend to run a little smaller than some other 35 series tires, so the clearance is better with those than some other brands.

[Msquared]

Originally Posted by Citrusbb

Thanks! I really like having a little more rubber between the wheel and the road. My 2015 1LE had 35 series, and I don’t understand why GM decided that 30 was better. Your answer really helps, thanks much. Maybe we’ll meet one day at a track near you.

GM went with 30s because a 305/35/20 is a huge/tall/heavy tire and it will hurt your performance. Unless you're going offroad and need extra ground clearance there is not a good reason to go with taller tires than stock. If you're really that concerned about having more sidewall, then you should step down to 19" wheels and run 35-series tires on those. You'll keep a similar overall diameter but gain sidewall height.

[arpad_m]

Originally Posted by Msquared

GM went with 30s because a 305/35/20 is a huge/tall/heavy tire and it will hurt your performance. Unless you're going offroad and need extra ground clearance there is not a good reason to go with taller tires than stock. If you're really that concerned about having more sidewall, then you should step down to 19" wheels and run 35-series tires on those. You'll keep a similar overall diameter but gain sidewall height.

PS4S 305/35/20 and 305/30/20 weigh almost the same (1 lb difference), and the 285/35/20 weighs 2 lbs more than the 285/30/20, making the total weight penalty 6 lbs for the 35 aspect ratio, not ideal but hardly a dealbreaker IMO. The ride is a bit nicer, too

That said, I'll most likely revert to the 30 series when these wear out, wheel well clearance is too narrow for my long term taste.

[Msquared]

Originally Posted by arpad_m

PS4S 305/35/20 and 305/30/20 weigh almost the same (1 lb difference), and the 285/35/20 weighs 2 lbs more than the 285/30/20, making the total weight penalty 6 lbs for the 35 aspect ratio, not ideal but hardly a dealbreaker IMO. The ride is a bit nicer, too

That extra mass is also further out on a longer radius due to the bigger diameter, so it's a bigger penalty than most would think. But still, that's the least of the problems. The raised roll centers and CG are bigger issues, the taller tire makes for a longer effective gear ratio, and the clearance is questionable, especially in back.