I tried searching but didnt come up with anything. But im interested in a wheel thats a 17x7.5 Et30. Would this fit my car? i tried calculating this out by knowing that a 17x8 ET35 would fit, which by my calcs would stick out 1mm more than the 17x7.5 et30...and it makes sense to me on paper...But im no wheel engineer so i figured i would ask :)

I would say without modification to the fender lips it is going to rub. You could always run narrow tires and more negative camber to limit the rubbing. You can also roll the fender lips.

Thanks for the reply Jim,
Ive been doing some calculations to try to figure this out. but im no expert so im hoping you can tell me if this sounds right. Originally i was looking at a 17x8 ET35 wheel. And now with the above mentioned 17x7.5 ET30 wheel.

Now offset is measured from the center line of the wheel right? So if i were to have a 17x7.5 ET35 (like the 17x8), then that would mean the 8" would have about 1/4" extra to each side of the wheel from the 17x7.5 right? And that 1/4" equates to about 6mm.

So if thats correct, then that means a 7.5" with that extra 6mm (or a 29mm offset) would stick out as far as the 8" et35 right? And in a low offset situation the only concern would be how far it stuck out and how close it got to the fender lip like you mentioned correct?

Sorry for the long post, or if its hard to follow. i was just hoping i could run my "theory" by an expert, as i am not one:stickoutt

Thanks again for the help

You are correct. The lower offset is not going to hurt the car. It is only going to make the wheels and tires stick out further toward the fender.

a 17x7.5 et 30 has 65.25mm from the mounting pad to the outside lip of the wheels. for referance a 17x8.5 et 41 (stock m3 wheel) has 66.95mm from back pad to outside face of the wheel. so you will be 1.5 mm farther inboard of a factory 17x8.5 wheel. these will fit all day long with absolutely no modification to any fender.

i run 17x7.5f and 17x8.5r with et 31 al around and i had to slightly roll the rears a little (not much at all)