for some reason all wagons bodies are slightly shifted to the left maike clearance on the pass side rear tighter that the driver's side. I had a set of 15x8 with 4 in back space and 255s and ran them on 4 different wagons. Every one would rub on a right hand turn anywhere over about 3mph.
I went down to 235 tire and under spirited driving (ahem) it would rub on right turns. Swapped to a stock SS rims which had more backspace and the problem went away.
You can roll the lip on the pass side for clearance (easy way) or as mentioned, re-center the body for that 1/2 inch difference (big PITA).