22.0 Collapse. The transverse tilt of the kingpin. Longitudinal inclination of the kingpin
Optimum driving dynamics and the lowest tire wear can only be achieved with perfect wheel alignment. With increased and uneven tire wear, as well as with insufficient stability while driving (poor directional stability when driving in a straight line, as well as poor handling when cornering) it is necessary to contact the workshop for optical measurement of the car.
It is not possible to measure a vehicle without an appropriate measurement setup, so only a description of the basic concepts regarding the determination of parameters is given here.
Convergence. collapse. The transverse tilt of the kingpin. Longitudinal inclination of the kingpin
Toe is called the lateral distance between the wheels. Positive toe means that the wheels, when measured at wheel center level, are slightly closer together in front than in the rear. Negative wheel alignment means that the front wheels are further apart at the front than at the rear. For RENAULT MEGANE and SCENIC vehicles, the front drive wheels have a negative toe angle of -10°± 10° (-1mm±1mm) and when moving, they tend to move inward.
Toe-in and camber reduce the stress generated by impacts caused by uneven road surfaces on the steering and reduce cornering friction.
Camber is the angle at which the plane of the wheel deviates from the vertical. Thus, the front wheels are inclined and, for example, with negative camber at the point of contact, the wheels with the ground are further apart than at the top.
Kingpin pitch is the angle between the pivot axis of the steering knuckle and a vertical line passing through the wheel reference point as viewed along the vehicle.
Kingpin pitch is the angle between the swing axis of the steering knuckle and a vertical line passing through the point of contact between the wheel and the roadway as viewed across the vehicle.
The longitudinal inclination of the kingpin significantly affects the stability of the front wheels when driving in a straight line. Too small a longitudinal angle of inclination of the kingpin contributes to the deviation of the wheels from the direction of movement on bad roads or with crosswinds and, in addition, it is difficult to return the steering mechanism to the middle position after making a turn.
Camber and caster are not adjustable. The convergence of the rear wheels is also not adjustable. If, during the measurement, the indicated wheel alignment angles exceed the nominal ones, as well as tolerances, then the reason for this lies in the wear or damage of the suspension parts.
Adjustment Conditions:
- Properly adjusted steering.
- Lack of play of tie rod ends and ball bearings, as well as hub bearings.
- Tire pressure must comply with the prescribed PJW
- The car must have the curb weight of the vehicle: unloaded, spare wheel, jack, full fuel tank.
- Previously, the car must be subjected to a strong draft.
- Properly adjusted steering.
- Runout of rims should not exceed 1.2 mm. Balance the wheels on the stand.