... and changing camber and generating cross weight

The steering geometry in combination with the actual steering angle influences the actual camber of the front tires. Due to the additional camber, the performance of the tires changes.

Steering kinematics are specified as a function of the axle ride height. The several parameters are specified by 5 ride height points. LapSim subsequently calculates a 2nd order equation based on these 5 points. The results of this equation are plotted as a line in the graphs.

Figure showing side view of the front axle of a vehicle with the caster and caster trail highlighted

Caster angle and trail

The caster angle is the angle along which the wheel turns, looking from the side to the vehicle. The caster angle in combination with the kingpin angle will increase the negative camber of the outside wheel and reduce the positive camber of the inside wheel due to steering input.

Figure showing the front view of the front axle with the kingpin inclination

Kingpin inclination

The kingpin angle is the angle of the steering axis looking from the front to the vehicle. Together with the caster angle, it generates extra camber while steering.

And secondly in combination with the steering trail, it causes a vertical movement of the tire, creating a load transfer. This principle is used in go-karts to the extreme.

Adjusting by drag and drop

Screenshot of the LapSim GUI showing a graph with the 3 steering parameters

The variables can be edited by pushing the left mouse button and drag the parameter to its new position. By clicking in the figure one can select a certain ride height position. The ride height points have to be edited in the edit boxes.

If the middle ride height position is selected, a change in a parameter will lead to a shift of the complete characteristic by the same amount.