How much more would 20" wheels slow down an S197 compared to 18" wheels? I am all about performance before show, but I have heard that 18" wheels look small on the S197. Is this true? some say that the 18" fill up the wheel well just fine...

 

i think they come stock with 18's, so i would just take a look at a stock one and see whatcha think.

personally im not that big of a fan of big ol rims unless yer totally donking it out, then im down.

 

I put 20's on my 2001 GT. And I noticed a big difference. My car still has ball's just for a stocker, but i did notice a change in the acceleration combo that with auto tranny and its very noticeable. I love the look of 20's tho its not something you see everyday on a mustang. I can correct the problem by findin a programmer that will let me calibrate for the tire and rim size. I tried to have ford program it but the biggest tire size that they had in there program was 19 inch. Have you thought about lowering the car? That will give you that filled out look.

 

By increasing the size of the wheel you are also increasing its rotational mass. This requires more power just to get the wheel moving and keep it moving. How much power is lost between 18" to 20" I'm not sure, and I don't feel like calculating it right now either. But I can assure you there will be a difference, I would stay on the side of performance and not get 20" rims. To reduce the gap between the fender and tire you could always lower your car which also gives a performance advantage in the form of a lower center of gravity.

 

lower it with no bigger than 18" rims if you're a performance nut. 17" or even 15" weld big and littles would be even better. Keep in mind that the width of the wheels and tires affects their weight dramatically. Getting too wide makes them just as heavy as making them too tall. I like 20's on a S197 but I'd stop at 18's nonetheless.

 

I was thinking lowering the car and going with some 18's. That should do the trick...

 

My 2007 GT came with the 17 inch bullitts and I think that 18's might look much better than the stock 17's. I have seen the S197's with the 20's and they look nice though.

 

Thanks for all the feedback

 

I think i might do 18x9.5 Chrome Steeda Ultra Lites. Or just keep the Stock 18" Bullitts when i get mine.

 

Those Steeda wheels look really nice.