differences in clearance

[fast400]

I'm scratching my head...I installed Foose 18"x9" rears. On the passenger side clearance is great, but on the driver side it looks like the outer lip could maybe touch if I hit a bump in the road.
Why would there be a difference?? The axle is centered as far a I can see.

[DynoDon]

You don't say what kind of car or anything with much detail, but I'll take a stab in the dark based on experience in my shop. Older American cars were built to a looser tolerance than modern cars. It is not uncommon to find quarter panels that very by a 1/4" or so from side to side. Additionally I have seen rear ends o leaf spring cars that were off by that same quarter. start adding up different tolerances and you can see why you might have rubbing problems. I would start by Measuring the rear end, not just looking at it and thinking it is even from side to side. Loosen the U Bolts and adjust as necessary