a. Caster is the angle of the steering axis from the vertical as viewed from the side and is shown in Fig. Positive caster is defined as the steering axis inclined toward the rear of the vehicle.

b. Camber is the angle of the tire/wheel with respect to the vertical as viewed from the front of the vehicle, as shown in Fig. Camber angles usually are very small, on the order of 1 ". Positive camber is defined as the top of the wheel being tilted away from the vehicle, whereas negative camber tilts the top of the wheel toward the vehicle.

c. Toe is defined as the difference of the distance between the leading edge of the wheels and the distance between the trailing edge of the wheels when viewed from above. Toe-in means the front of the wheels are closer than the rear; toe-out implies the opposite. Figure shows both cases.

d. King Pin axis inclination (a.k.a. Steering Axis Inclination) is the angle from the vertical defined by the centerline passing through the upper and lower ball joints. Usually, the upper ball joint is closer to the vehicle centerline than the lower, as shown in Fig.

e. Combined Angle (a.k.a. Included Angle) is the summation of the camber angle and steering axis inclination. In other words, it is the angle formed in the vertical plane between the wheel centre line and king pin centre line.