The tire contact patch is offset from the center of the wheel at hub height when we add camber to a wheel. The chart shows how far offset the contact patch center is related to the wheel center at hub height. This is important to know when stringing a car at hub height which is a common practice. If we string along the rear tire bulge to the front tire, the front tire-to-string should be a gap equal to the chart offsets. If the rear and front wheels have camber, then subtract the rear offset from the front offset and make your front tire gap that dimension.