I have a 91 Camaro RS with the factory 16" rims. I am looking at a new set of rims, but they have a different backspace offset and bolt pattern (I know, why bother right, but I really like the look).

My factory rims I believe have a backspace of 4.75 up front and 5.25 in the back. If my math is right, that makes the offset .5 up front, and 1" in the back.

The new rims are only 7" wide not 8" like the factory ones. The offset is 47mm, which based on my math would make the Backspace 5.6"

In order to keep the factory look outside, I would think my main concern would be the distance from the mounting plate and the front of the rim. SO, long story even longer...

For spacers/adapters I would need 5x4.75 to 5x115, and I would need the front ones to be 1.85" and the rear ones to be 1.35"...

Am I even close??

 

Oh, figured I would give the last of the info of how I figured it.

I basically found the Backspace numbers for my Factory rims, AND the rims I want. I took that number and subtracted it from the total rim width (8-4.75=3.25). I called that new number my frontspace (if anyone knows the real term for it let me know so I can feel less like a fool). Then I did the same for my new rims. (7-5.6=1.4)

now that I had these numbers I just calculated the difference between old rim and new rim. (3.25-1.4=1.85) so I found there was 1.85" more space between the mounting plate and the front of the factory rim, than the new rim would have, meaning a 1.85" spacer would correct that?? am I at least on the right track? lol

 

Its a bit off. Factory wheels are zero offset or 4.5" of backspacing front and +16mm offset or 5.125 backspacing rear. Keep in mind that wheels are about 1" wider than advertised because of how they are measured.

 

OH, ok. So I would want to use (8-4.5=3.5) and (7-5.6=1.4) so a spacer of 2.1" up front?

 

oops, below is the link

http://www.tacreationsusa.com/camaro_wheels.htm

 

Ok I think I got it.

Old rim:
16x8 0 offset up front, and 16mm in back

New Rim:
17x7 47mm Offset all 4.

SO in order to make the face of the rim land in the same spot as the factory ones after mounting, I would need the below.

2.35" spacers up front
1.72 in back.

Is that more accurate? Also, is a 2.35" spacer safe? I mean really it just puts the rim back to the factory mounting spot right?