Chris07GT

I want to upgrade my wheels/tires pretty soon. I haven't decided on rims yet (I really like the Shelby CS69). My question is more about sizes. What (if any) suspension changes do I need to make if I go to the 18's? Same question for the 20's. I also really like the idea of staggered sizes. What's the largest tire I can put on the rear without having any sticking out of the wheelwell?

F1Fan

Hi Chris07GT,

How do you drive? Does your car have a modified handling oriented suspension? How much lower than stock is the chassis ride height set? Are you only after looks or is handling important to you too? What about ride quality? Would you trade handling for ride?

No changes are required for any well designed wheel upgrade using wheels with the proper offset for the car. 18" wheels and tires will out perform and ride better than 20" wheels and tires of comperable quality. If you had custom 2 or 3 piece wheels made for the S197GT and ran a Watt's Link on the rear axle you could squeeze up to an 11" wide wheel under the wheelwells but there are no suitably sized tires larger than a 285/40x18.

Staggered wheel and tire sizes are a problem for handling performance and a waste of friction and tire drag for a N/A motored car. A staggered wheel and tire combo looks good but can cause massive understeer which the car already has plenty of. Stick with equal size tires all around for best handling results unless you have 450RWHP+ adn are a world class driver, you just can't take advantage of the larger tires without a lot of power and suspension specifically tuned for a staggered whee and tire combo.

HTH!