Abstract: An improved wheel alignment system and method is disclosed. This invention is a kinetic alignment system combining a geometric wheel aligner which measures toe angle with reference to the sidewall of a tire, and a dynamic wheel aligner which measures toe and camber angles with reference to the tread of the tire in order to rapidly and simultaneously measure both the position of a vehicle's wheel and the roll of the tire associated with the wheel. The geometric aligner of this invention includes (a) an improved pivot assembly that reduces scrub and the corresponding false position readings that otherwise result from the scuffing of the geometric apparatus across the sidewall of the tire when the wheel's plane of rotation changes, and (b) an improved striker assembly so as better to strike the sidewall of a tire at the tire's center line and, where the exact center line is missed, to self-correct for the unbalanced tire forces resulting from the missed strike.

Abstract: Apparatus and method are provided for use in determining information relating to the plane of rotation of an object, particularly a vehicle wheel. The apparatus includes a probe that is maintained at the same contact point relative to the wheel during the rotation of the wheel. The position of the probe is monitored and position-related data is analyzed by a processing system. The processing system implements a least squares method for defining the plane of rotation utilizing a number of the position-related data points, which were obtained during rotation of the wheel. In one embodiment, the probe is connected to a pivotable wobble plate for use in maintaining a predetermined position of the probe relative to the wheel during rotation thereof. A carriage assembly also acts to maintain the predetermined position of the probe. In another embodiment, instead of a carriage assembly, rotatable arms and counter-weight are employed so that the probe moves as a direct result of rotation of the wheel.