I'm not opposed to pie cutting the the 1/4 to open up the wheelwell, but do not want to go as far as I did on the old 1/4 panels, as I want to reinstall the original wheeelwell moldings, and rocker panel moldings. I'm thinking the radial will not grow like the bias ply slicks, and it shouldn't be as much of a problem if it's tight. I want the wheelwell filled with tire.
The radials definitely don't grow and distort as much as the bias ply tires do - I have the 295/65's on mine and it's within about a pinky's width of clearance to the leading edge of the wheelwell trim and I've never had issues with it rubbing.
