Suspension and Steering (part 2)

Wheel Alignment

Wheel alignment should be checked whenever new tires are installed, suspension components installed, when the vehicle has encountered a major road hazard or curb and any time unusual tire wear patterns appear.
Wheel Alignment is the Measurement of complex suspension angles and the adjustment of a variety of suspension components. It is a suspension tuning tool which greatly influences the vehicle's handling and tire wear.

Wheel alignment consists of adjusting the angles of the wheels so that they are parallel to each other and perpendicular to the ground, thus maximizing tire life and ensures straight and true tracking along a straight and level road.

The primary static suspension angles that need to be measured and adjusted are caster, camber, toe and thrust angle. 

Camber is the angle of the wheel, measured in degrees, if the top of the wheel is tilted out then the camber is positive, if it's tilted in, then the camber is negative.

Caster is the angle of the steering pivot, measured in degrees.

Toe in and out

      

Steering Axis Inclination (SAI) is the measurement in degrees of the steering pivot line when viewed from the front of the vehicle. On a SHORT-LONG ARM (SLA) SUSPENSION the line runs through the upper and lower ball joints.

Thrust angle is the direction that the rear wheels are pointing in relation to the center line of the vehicle.

Steering box

Shock Absorbers

In a vehicle, shock absorbers reduce the effect of travelling over rough ground, leading to improved ride quality and increase in comfort. While shock absorbers serve the purpose of limiting excessive suspension movement, their intended sole purpose is to dampen spring oscillations. Shock absorbers use oil and gasses to absorb excess energy from the springs. Spring rates are chosen by the manufacturer based on the weight of the vehicle, loaded and unloaded.

Steering Safety

For safety reasons all modern cars feature a collapsible steering column (energy absorbing steering column) which will collapse in the event of a heavy frontal impact to avoid excessive injuries to the driver. Air bags are also generally fitted as standard. Non-collapsible steering columns fitted to older vehicles 

Wheel Bearing