Wheel offset and backspacing can be a little confusing but are absolutely crucial when ensuring proper fitment of aftermarket or replacement custom wheels.
In order to determine wheel offset, you first need to establish two locations on the wheel. The CENTER-LINE and the MOUNTING FACE. The center-line is the line running around and through the barrel of the wheel, marking the center of the wheel’s width. The mounting face, or axle pad is the flat surface on the back side of the wheel’s plate, which mounts to the vehicle’s brake rotors when the wheel is mounted on the vehicle. The distance between these two locations is measured in millimeters and is referred to as the wheel offset.