a. The Scrub radius is the distance in front view between the king pin axis and the centre of the contact patch of the wheel, where both would theoretically touch the road.

b. 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.

c. 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.

d. 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.

e. Understeer and Oversteer are vehicle dynamics terms used to describe the sensitivity of a vehicle to steering. Simply put, oversteer is what occurs when a car turns (steers) by more than (over) the amount commanded by the driver. Conversely, understeer is what occurs when a car steers less than (under) the amount commanded by the driver.