Steering Geometry 1

1. As per the parametric study done in SolidWorks, the caster angle is +5.38 degrees.

2. The Mechanical trail is +9.41 mm

3. Kingpin inclination angle is +10.01 degrees.

4. The scrub radius from tire-road contact point is +32.35mm

5. The kingpin lateral offset is 84 mm (2D if you look from the front view). In 3D, it is 85.77 mm to the wheel centre.

6. Given, Fy = 2000N; Nt = 25mm; from the parametric study mechanical trail Mt = 9.41mm

So, FY*(Nt+Mt) = restoring moment
2000*(25+9.41) = 68,820 Nmm = 68.82 Nm

This is the restoring moment of the wheel.

Shortening, the upper arm length will shift the upper arm ball joint point towards the +ve Y-axis and result in a higher Kingpin inclination angle which will generate a negative scrub radius. A negative scrub radius is preferable in FWD cars to reduce torque steer.

Please refer to the CAD file attached to cross-check the values.