If it is not possible to check all settings, then it is imperative to check the camber and toe of the front wheels.
Wheel alignment
As a rule, the front wheels should have a positive convergence, since when driving in a straight line they scatter a little to the sides, due to play in the bearings and suspension of the wheels, in the hinges of the swing arms. Positive wheel alignment compensates for this. For positive toe-in, the distance between the front points of the wheel, measured at the level of the center of the wheel, must be less than the distance between the rear points. However, in the front-wheel drive OPEL KADETT, rear-directed forces tend to bring the front parts of the wheels together. For this reason, the OPEL KADETT must be set to negative toe, those front wheels at center height in the front must be spread apart more than in the rear.
Camber and lateral inclination of the axis of rotation of the wheel
Camber and lateral tilt of the wheel axis reduce the effect of road shocks on steering and ensures minimal friction when cornering. Camber is the angle at which the plane of the wheel deviates from the vertical axis. Thus, the wheels are located obliquely. Depending on the position, they speak of positive and negative camber. With positive camber, the lower parts of the wheels are closer than the upper ones.
The transverse inclination of the axis of rotation of the wheel is the angle between the axis of rotation of the steering knuckle and the vertical plane at the point where the wheel touches the road.
Due to the camber and lateral inclination of the axis of rotation, the points of contact of the wheels of the road are located closer to the vertical axis of the steering knuckle and, therefore, the so-called running-in shoulder is smaller. The smaller the break-in shoulder, the easier the control. Also, road impacts act on steering rods much less.
The OPEL KADETT has a negative break-in arm. Thanks to this, higher directional stability is achieved with the same effect of the brakes on the front wheel.
Longitudinal inclination of the axis of rotation of the wheel (run-out)
Coasting significantly affects the rectilinear movement of the car. Too little overrun causes the vehicle to become unstable on bad roads and in crosswinds. In addition, it is difficult to return the steering wheel to the middle position. The runout is set by design due to the tilt of the steering knuckles and is not adjustable, however, must be checked after the repair of the front suspension (performed in the workshop).
Adjustment
It is advisable to measure the parameters using an optical device for checking the installation of wheels, which works autonomously. The following conditions must be met for each measurement.
- Set tire pressure
- Accurate horizontal position
- Vehicle with its own weight (with spare wheel and, if possible, with a half-filled fuel tank)
- No unacceptable steering wheel play
- No unacceptable play in the wheel suspension
- Rock the car several times
- Flawless rim flange
- Both front seats are loaded with a mass of 70 kg each
- Uniform and flawless tread pattern
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