most prominent advantage lies in the large space between the left and right wheels together with no camber angle of the body, and a sunken rear wheel of the swing arm suspension to balance the vehicle body. 3. Specifications of wheel alignment parameters If the wheels enjoy good geometric alignment, the fuel economic efficiency and tire service life will be improved. (1) Kingpin caster angle: It refers to the angle between the highest point of the wheel steering center and the vertical direction in the view at the side of the vehicle, as shown in Fig. 2-3. The caster angle is positive (+), while the front rake angle is negative.
The retroversion of the kingpin will influence the control on the direction of the steering mechanism, but not on the wear and tear of the wheels. In case of a larger positive kingpin caster angle of a wheel than that of other wheels, this wheel will drive towards the center line of the vehicle and the vehicle will move forwards towards the side with a smaller positive kingpin caster angle. Fig. 2-3 (2) Wheel camber angle: Extroversion is viewed from the front of the vehicle. It refers to the angle of the wheel off the vertical direction as shown in Fig. 2-4. If the top point of the angle is towards outside, the camber angle is positive (+); while towards inside, it is negative (-).
Extroversion will not only influence the control on the direction, but also the wear and tear of the wheels. An excessive extroversion will result in a worn wheel and cause the vehicle to move towards the largest camber angle or to one side. Fig. 2-4 (3) Toe-in of wheel: It refers to that the weel moves inward off the geometric center line/thrust line. 106