Re: back space not sure
The confusion seemed to stem from years ago when it was measured from the mounting bead. eg. It used to be a 8" wheel with 4" BS was zero offset.
With the advent of aluminum wheels & positive offsets there was a lot more problems with wheel interference to adjacent suspension components. Now wheels are based on offset with respect to the tire centerline vs. mounting face. The backspace is the rear dimension with a straight edge acoss the rear of the wheel. This is typically approx 1/2" more than the bead dimension. The same 8" wheel w/ zero offset would have roughly a 4.5" backspace.
Last edited by Lonnie P; Feb 27th, 11 at 08:35 AM.