Determination of chassis parameters

Optimum vehicle dynamics and minimal tire wear can only be achieved with perfect wheel alignment. With increased and uneven tire wear, as well as with poor driving stability - with poor stabilization in straight-line movement and poor steering performance when cornering - you need to contact a service station for optical determination of the running gear parameters.

Chassis measurements can only be carried out using a suitable measuring system. Therefore, I limit myself here to a description of the main parameters determined during measurements.

Toe and camber / transverse and longitudinal inclination of the kingpin axis (wheel axis)

Wheel toe-in is the difference between the distances measured in front and behind the steered wheels at the height of their axis of rotation. With positive wheel alignment, the distance between the wheels in front is less than the distance in the rear. With negative toe-in, on the contrary, the smaller distance between the wheels will be at the rear.

FORD SCORPIO	Positive wheel alignment of the front axle
	Control value, mm	Adjustment value, mm
By 8/94	+4.5 to -0.5	2.0±1.0
From 9/94	+3.0 to +1.0	2.0±1.0

Camber and lateral tilt of the kingpin axle reduce the transmission of shock loads from the road side to the steering and maintain minimal friction of the wheels on the road when cornering.

Camber is the inclination of the plane of the front wheel relative to the vertical plane (the figure shows a positive camber with the wheel plane tilted at an angle α).


The transverse inclination of the kingpin axis is characterized by the angle β between the kingpin axis and the vertical passing through the point of contact of the tire with the road, when viewed in the direction of the vehicle.

The longitudinal inclination of the kingpin axis is characterized by the angle between the axis of the kingpin and the vertical passing through the point of contact of the tire with the road, when viewed in a direction perpendicular to the direction of the vehicle. The longitudinal inclination of the kingpin has a proportional effect on the straightness of the movement of the front wheels. A slight longitudinal inclination of the kingpin causes a deviation from a straight-line movement on a bad road or with a side wind, and also forces the steering to not fully return to the neutral position after a turn.



Prerequisites for checking the running gear parameters:

• Steering is properly adjusted.
• No unacceptable gaps in tie rod joints and suspension ball joints, rims and tires in perfect condition.
• Tire pressure correctly adjusted
• The car must be unloaded, the spare wheel and the onboard jack are in the places intended for them. The car itself must be empty.
• Vehicle suspensions are heavily pre-loaded and then unloaded.