I have Racing Hart C4s 9X19 front with offset of 26 and 10.5X19 Rear with a 22 offset. Tires are 245/35 front and 275/35 Rear. Heres the issue: Over deep bumps there is a rubbing sound in the Right Rear area only. I dont know if the hatch back version of the Z has the Gas Fill line routed thru the inside of the fender well [the roadster does] or not, but that is my best guess. I have taken off the wheel and looked for any rub marks with no success. No damage to the tire or rim or underbody are evident. Any ideas? (my next step is to tape white paper under the fender well and hit a few deep bumps as a touch indicator).

 

It's your offset on the rear. You are rubbing the inside of the fender well. This has been posted several times that to run 10.5s you have to roll the rear fenders.

You should have gone with something around a +38 on the rear for it not to rub.

 

Just out of curiosity, why only the right rear? And no signs of rub on the tire or fender flap? (that was the first place I looked).

What is the "No Rub" rim width / offset? or can you run 10.5 with the recommended +38 (another Inch + inward on the tire, right?)