The angles of the front wheels determine the geometry of the position of the latter relative to the suspension of the car and the road surface. Violation of the adjustment of this geometry leads to a decrease in the controllability of the car and an increase in the rate of tire wear. The number of angles of installation of the front wheels of the car to be controlled includes camber, run-out (the angle of the longitudinal inclination of the axis of rotation of the wheel) and convergence. Only one of the parameters is subject to adjustment - convergence, moreover, both the front and rear wheels of the car. The camber and runout of the front wheels should be checked on a regular basis to assess the amount of wear on the suspension and steering components.
Adjusting the wheel alignment angles is one of the procedures requiring special measurement accuracy, for the high-quality implementation of which it is necessary to have special, rather bulky and expensive equipment. It would be best to entrust this work to professional car service mechanics. Below, for a general understanding, are the definitions of each of the controlled car wheel alignment angles, the knowledge of which will facilitate the communication of the car owner with the car service personnel.
Convergence is the amount of convergence to each other of the front edges of the wheels of the car. Such a violation of the parallelism of the wheels allows minimizing tread wear due to skidding when making turns. At zero convergence, the distance between the front edges of the wheels is equal to the distance between their rear edges. Normal convergence is usually less than a fraction of an inch (1 inch = 2.54 cm). Adjustment of the convergence of the front wheels is carried out by adjusting the length of the steering rods by changing the position of their tips. To adjust the rear wheel toe-in, a special adjustment cam bolt is provided, screwed into the inner end of the rear suspension control arm. Violation of the adjustment of convergence leads to accelerated wear of the tire tread due to their slippage on the road surface.
Camber is the angle of inclination of the plane of the wheels relative to the vertical. If the wheels are tilted with their upper edges outward, the camber is called positive, and vice versa. Camber is measured in degrees. The correct camber adjustment determines the size and position of the tread contact patch with the road and allows you to compensate for changes in suspension geometry during cornering and when driving on uneven road surfaces. On the considered models of cars, the possibility of adjusting the camber is not provided.
Runout is the angle of deviation from the vertical of the axis of rotation of the wheel in the plane of the latter. If the axis of rotation is tilted back, the coast is called positive, vice versa. Adjustment of the run-out of the front wheels is carried out by selecting distance washers placed under the push rods of the suspension.