I'm not sure about your measurement. Here's a cool sketch from TireRack.



Rim width = 7.5 inches
Doesn't matter exactly where you measured, as long as it's EXACTLY the same place inside vs. outside. You could lay the tire down on the floor; lay a straightedge (carpenter's level?) across the top of the tire sidewalls, & measure between spokes, from the straightedge to the floor.

Back-spacing = 6.0 inches
From mounting surface, to the same place you measured the total width. Say the wheel is laying down on the floor, you measure from the mounting surface to the floor.

So rim center is at 3.75" from the inside & the mounting surface is 6.0" from the inside.
Offset = (6.0 - 3.75) = 2.25" = 57mm

 

Thanks, so would these rims work after all? Do you know anything about general exclaim UHP ZR Rated brand tires? I found a set brand new for cheap. They are 225/40/18.

I was thinking about taking one of the stock rims off this weekend and mount the aftermarket rim. The rim has no tire, but what should i be looking for, as far as fitment? Should i mount on the front or rear, when testing.

 

Generally the front is where clearance can be a problem. Your measured offset is too large (if you measured it correctly) so you can look for the inboard side of the rim rubbing against the brake or against the uppper control arm.

If you had a tire mounted, you would look for the tire sidewall rubbing against the shock/spring. Maybe you can judge the position of the tire??? But that's kinda shaky guesswork if the tire is not actually mounted.

With a tire, you would also look for the tire rubbing against the plastic inner fender liner, at any extreme position of steering or suspension travel.

 

This One Member!

 

thanks for your help. One last question, im concerned because i might have wasted money on the rims, but would the stamp on the inner rim that says ET: 4l5 suggest the offset is 45mm, and probably my measurments are off. the rims came off a mercedes. If it is a 45, would this fit. Better yet i will clean the inner wheel tonight, and take a picture of it , and post the picture. That will probably help you and me.

 

The ET 45 stamp sounds like the offset. I don't understand the slash mark unless it's just a defect in the casting or something silly like that.

Look at the TireRack drawing & notice the measurement is to the inside surfaces of the rim, where the bead of the tire sits. That's not easy to measure against, and there's lots of rims where the EXTERNAL shape/thickness of the rim beads don't match (inboard vs. outboard).

 

So i did a quick 5 minute cleaning, and took pics of the underside of the rim.