Variable Ratio Steering With variable ratio steering, as the steering moves away from the straight-ahead position, the ratio, and therefore, the mechanical advantage, increases progressively. . The steering box gear ratio increases output torque, reducing the effort the driver must apply. . Power Steering Power steering systems produce assistance that reduce the driver's effort. They are of most benefit during slow cornering and when parking. . When a load is applied to the steering system, the torsion bar twists, causing relative movement of the inner and outer members of the rotary valve.
Assistance progressively rises as the torsion bar twist increases. .
Power Steering Pumps Power steering pumps have a flow-control valve to vary fluid flow and system pressures. A pressure relief valve prevents excessive pressures developing when the steering is on full-lock. A flexible joint connects the steering column to the input shaft of the steering box. It allows alignment of the steering column with the steering box. Linkages A panhard rod can restrict lateral movement of the rear axle during cornering.