Wheel Offset, Backspace & Bolt Circle Diagram - Wheel Measurement Guide

This document is a labeled cross-section diagram of an automotive wheel (rim), illustrating the standard dimensional terminology used when measuring or selecting wheels. The drawing shows a wheel in section view with callouts identifying: Wheel Offset (the distance between the wheel centerline and the mounting pad), Backspace (measured from the mounting surface to the inboard rim edge), Wheel Centerline (marked with a CL symbol), Bolt Circle Diameter, Wheel Diameter, Wheel Width, and the Mounting Pad. It also distinguishes the two faces of the wheel, labeling the outer face as the 'Street Side' and the inner face as the 'Drum Side.' Additionally, an arrow points to the location on the wheel where the maximum load rating is stamped ('Look for max. load rating here'). A reader can learn from this diagram how the key wheel fitment measurements relate to one another physically — for example, that offset is measured relative to the wheel centerline while backspace is measured from the mounting pad to the back lip — which is essential knowledge for choosing wheels that clear brakes, suspension, and fenders. The diagram is generic and not specific to any make, model, or year of vehicle.