As I recall, my 12A wheels had about 40mm backspacing. I'm looking to run 225/45 tires, so would 25-30mm 15x7s work out? I was thinking of 8" wheels and 15mm backspacing, but it seems like it'd be too much tire. I'm looking at ordering a set of Diamonds in 15x7 4x4.5 and just want to work out backspacing. Would 25mm backspacing sound right?

 

Critoris,
I think you may be talking about two differnt things (back spacing and offset). My 12A first gen has wheels with a 12 mm offset and a 4 " (101.6 mm). I think that when you order the wheels you will want a 3.5" or 4" offset.

Another issue is bolt pattern. The 12A first gen has the strange 4 by 110mm wheel spacing. It is not the same as 4 by 4", 4 by 4 1/4", or 4 by 4 1/2". Folks will try to sell you a 4 by 4 1/4" and tell you it is the same. It is not, it is 108mm and you have to kind of squezze it on. And, if your wheels are not hub centric it will not self-center.

I know from experince. I bought a set of 4 by 4 1/4" (108mm) rims. I saw a photos of a first gen with them on, so I thought I was safe. Nope, they just do not work.

If Diamond are going to make you the wheels get the 4 by 110mm with a 4" back space.

Good luck to you!

 

I've got SE spindles and rear axles. That's why I'm starting from scratch, per se. Will a 4" backspace leave room against the struts for 225 tires?

 

if you have gsl-se suspension f&r you will need more backspacing than non gsl-se cars. A 15x7 wheel with only 4" of backspacing with 225 tires will clear the struts with ease, but they will stick out like a **** on the fender side and probably rub.

 

I was looking at my rear susp and I think a 4 1/2 - 5" backspacing will work in the rears.

 

it's more like 5 3/8" - 5 5/8"

a 1/2" (~13mm) inch makes a big difference