collapse called the angle of inclination of the plane of the wheel 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 contact patch of the treads with the road surface and allows you to compensate for changes in suspension geometry that occur during cornering and when the car is moving on uneven road surfaces.
Convergence (convergence) called 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 by preventing 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). Violation of the adjustment of convergence leads to accelerated wear of the tire tread due to their slippage on the road surface.
coasting called angle of longitudinal inclination of the kingpin/axle of rotation of the wheel, i.e., the angle of deviation of a given axis from the vertical in the plane of the rim. If the pivot/kingpin is tilted back, the coast is said to be positive, and vice versa.
Note. By analogy, the angle of the transverse inclination of the axis of rotation of the wheel is the angle of deviation of an imaginary kingpin from the vertical in a plane perpendicular to the plane of symmetry of the car.
Value limit angles of rotation of the front wheels car should be lowered while increasing the size of the latter. The distance from the edge of the tire of the wheel turned to the stop to the trailing arm of the suspension must be about 2 cm, otherwise an appropriate adjustment is necessary (see Section Checking and adjusting the limit angles of rotation of the front wheels).
A general check of the suspension geometry is carried out on a special stand in a specialized workshop.
Conditions for checking wheel alignment
Checking the installation angles of the car requires a specially equipped overpass. Before starting the test, make sure that the following conditions are met:
- The air pressure in the tires corresponds to the nominal;
- The front wheels are mounted straight;
- The car is not loaded, the fuel tank is full;
- Elements of the car's suspension are upset with force;
- The steering gear is correctly adjusted;
- Backlash in the tie rod ends and suspension ball joints do not go beyond the permissible limits;
- The tread depth of tires mounted on wheels of the same axle is the same.