US Patent 7185438 Method and apparatus for determining vehicle wheel geometry

The invention is a method of determining the geometry of a wheel of a vehicle and/or the geometry of the associated support or drive structure. In one embodiment, a gauge includes caster and camber vials or an electro-mechanical sensor for outputting caster and camber angle to a display. In use, the gauge is aligned with or referenced to an indicator, such as a slot or marking. In one embodiment, the indicator has a reference position of zero degrees caster angle. The gauge measures the current position of the indicator compared to its reference position. The gauge includes a connecting element for maintaining it in alignment with the indicator, such as a threaded ring which engages the spindle or a magnetic ring engaging a wheel hub.