Wheel Offset & Backspacing Diagram - Centerline and Hub Mounting Surface Explained

This document is a labeled cross-section diagram of an automotive wheel, illustrating the key dimensional reference points used to describe wheel fitment. The diagram shows a wheel rim in profile (cut vertically through its center), with four labeled elements: the 'Centerline' (marked with a red vertical line through the middle of the rim width), the 'Offset' (indicated as the distance between the centerline and the hub mounting surface), the 'hub mounting surface' (pointed out in green at the flat pad where the wheel bolts to the hub), and 'Backspacing' (shown in magenta at the bottom, measuring from the hub mounting surface to the inboard rim edge). A reader can learn how these measurements relate to one another: offset is measured from the wheel's centerline to the mounting surface, while backspacing is measured from the mounting surface to the back lip of the rim. The diagram contains no text beyond these four labels — there are no part numbers, vehicle years, models, or specifications. It appears to be a generic educational illustration applicable to any vehicle's wheels, uploaded as part of a set of wheel offset and backspacing reference images.