Pic. 25.1. Camber angles, longitudinal inclination of the axis of rotation of the wheel about convergence
A minus B = C (collapse in degrees)
D = longitudinal inclination of the axis of rotation of the ear (expressed in degrees)
E minus F = convergence (measured in millimeters)
G = convergence (expressed in degrees)
Adjusting the wheel alignment angles is a very precise procedure, the quality of which requires special, rather bulky and expensive equipment. Therefore, it is recommended to entrust this work to the mechanics of properly equipped service stations. Below, for a general understanding, definitions are given for each of the wheel alignment angles of the car, the knowledge of which will facilitate the communication of the car owner with the car service personnel.
Convergence is the amount of convergence of the front edges of the wheels to each other. The purpose of having a toe is to ensure that the wheels oscillate correctly. With zero convergence, the distance between the front edges of the wheels is equal to the distance between their rear edges. In fact, the convergence is only a few millimeters. The front wheel toe-in is adjusted by adjusting the effective length of the steering rods (changing the position of the tips on the steering rods). Rear wheel toe adjustment is done either with threaded adjusters on the rear wishbones or with cams at the inner ends of the arms (depending on the modal year). Incorrect toe adjustment leads to accelerated wear or improper wear of tire treads due to their slippage on the road surface.
Camber is the angle of inclination of the plane of the wheels relative to the vertical, when viewed from the front or rear of the car. If the upper edges of the wheels are tilted outward, the camber is called positive, if inward - negative. Camber angle is measured in degrees. The correct camber adjustment determines the size and position of the tread contact patch with the roadway and allows you to compensate for changes in suspension geometry when cornering and when the car is driving on uneven road surfaces.
Pitch is the angle of inclination of the wheel axis from the vertical. If the axis of rotation is tilted backwards, the pitch is called positive. If forward - negative. Too little caster can cause yaw in the front end of the vehicle, while too much caster can cause increased steering effort.