Steering Geometry Concepts

Wheel alignment: the front wheels are slightly closer together at the front than at the rear (roll towards each other). This evens out the friction between the wheel and the road, which tends to push the left wheel to the left and the right wheel to the right. The convergence does not allow beating of wheels and erasing of tires. In a corner, the wheel inner to it turns more to support steering movement and steering forces than the wheel outer to the corner - wheel toe turns into divergence, (the rear of the wheels is closer than the front).

Camber: vertical tilt of the wheels. Reduces the impact of the road on steering parts, reduces the force applied to turn the wheels, and the friction of the wheels on the road. The front wheels of the Focus have a positive camber - at the top in the wheel arch they are moved apart a little more than at the bottom near the ground.

Cross slope: tilt of the steering axis of rotation vertically. If you draw an imaginary line from this axis to the ground and measure the distance to the center line through the wheel (wheel bearing center), you get the turning radius of the steering. The turning radius should be as small as possible in order to reduce the forces opposing the steering. The lateral inclination of the wheels together with the longitudinal inclination contribute to the fact that the car rises slightly when the wheels are turned. When the steering wheel is released, the wheels themselves are set to the middle position (stabilizing moment).


Longitudinal slope: distance (in the direction of travel) between an imaginary line extended from the steering axis to the ground and the center of the tire bearing surface. Due to the longitudinal inclination, the wheels are pulled together (not moving). The tightened wheels themselves tend to become in a position of rectilinear movement and steadily adhere to it (effect of a trolley-tray with a tea set).