michiganpat
Well-Known Member
an easy way to convert offset to backspace is: the advertised wheel width is the inside dimension from bead seat to bead seat. the actual outside to outside dimension (if you measure it with a tape measure) is typically 1" wider. offset is the distance from the center of the rim. positive is towards the outer face, negative towards the inner. backspace will be outside to outside width of wheel divided by 2, then add the offset. so a +6.35mm wheel (.25") on a 7" width (8" wide overall) will be (8/2)+.25=4.25". a +6.35mm offset on a 5.5" wheel will only be 3.5" backspace, but the same offset on an 8" wheel is 4.75" backspace.
