u/rubbish777

I ordered a set of 4 18x10.5 rims with +20 offset to have a square set up on my s550 mustang. I am on stock suspension and height. I know it will have poke which is what im going for but need help on tire size that won't rub too much.

Ex: 275/40/18r ?

Any help is greatly appreciated as im new to this stuff.

Thanks!! :)