You can. I used to run 15x7's on the back and 14's on the front when I had the black Rallys on the back. The Halibrand clone front wheels are skinny 15x4 1/2, the rears are 15x7. Front tires are 165 80 15 and the rears are 235 70 15. I have 255 60/15's on 15x7 rally's on mu swinger. I need to try them on my 66 someday just to see how they fit.
