Backspacing

A wheel dimension measured from the hub mounting surface to the inner sidewall of the tire, usually measured in Inches. It determines how much tire you can fit without rubbing on the inner fender. It does not define how the wheel will line up with the bodywork of the car. For that, you must calculate "frontspacing", by subtracting backspacing from the wheel width, and match it up with your oem frontspacing.