An exact check of the wheel alignment can only be carried out on a suitable measuring stand. Therefore, this chapter describes only the basic concepts, as well as the procedure for adjusting the toe-in.
Basic concepts
Wheel alignment
Convergence is the difference in distance between the side surfaces of the front wheels in front and behind. The front wheels must be toe-in because the forward deflection and rolling resistance cause the wheels to lean slightly outward due to play in the wheel bearings, suspension and tie-rod joints. The convergence compensates for this deviation. To set the toe-in, the front wheels are adjusted in such a way that the distance measured between the wheels at the middle of their height is less at the front than at the rear, i.e. the front wheels are somewhat closer to each other.
Camber and lateral inclination of the axle of the wheels
Camber and lateral tilt of the wheels reduce steering shock caused by uneven road surfaces and minimize tire friction when driving in a curve.
Camber is the angle at which the plane of the wheel deviates from the vertical. Thus, the front wheels are mounted obliquely and at the point of contact with the ground are closer to each other than from above.
The lateral inclination of the wheels is the angle between the axis of the steering knuckle and a vertical line drawn through the point where the tire touches the ground, looking in the direction of the longitudinal axis of the vehicle.
Due to the camber angles and the inclination of the axis of rotation of the wheels, the points of contact of the wheels with the road are close to the axis of rotation of the steering knuckles. As a result, small values of the running-in shoulder are maintained. The smaller this value. the less effort is required to turn the wheels. In addition, the steering is significantly less affected by bumps due to road irregularities.
In Opel Vectra/Calibra cars, the break-in arm is negative. This maintains maximum directional stability in the event of uneven braking of the front wheels.
Longitudinal inclination of an axis of a rotary fist
The longitudinal inclination of the axis of the steering knuckle largely affects the stability when driving. Too little lean causes the vehicle to pull to the side on poor road surfaces and crosswinds, and makes it difficult to return the steering wheel to the straight ahead position when exiting a corner. The inclination of the axis of the steering knuckle is set constructively, by means of a certain angle of its rotation, and is not regulated. The value of this angle, however, must be checked after repair of the front suspension or front axle beam (performed in the workshop).
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