As far as I have been able to figure out, once you determine the backspacing, the offset is irrelevant when it comes to inside clearance. The backspace is the distance from the backside of the hub to the back lip of the wheel. The offset and backspace are directly related except offset is used to determine the distance off center the front of the flange is with respect to the center line of the wheel. The more positive the offset, the more inset the wheel will sit in the fender well and vise versa...Therefore the larger the backspace the more positive the offset will be.
I could be confused, but I'm sure someone will jump in if I have it wrong...
Last edited by Slider78; 06-09-2011 at 08:48 PM.