Introduced in the 1950's, power steering became standard issue by the 1970's. As the driver turns the steering wheel, the input is amplified into rotating the steering column - magnifying driver steering input, facilitating precision cornering requiring less force. The benefit of power steering is especially evident while manoeuvring at low speed. If you ever drive a vehicle without power steering, the distinction is very immediate and very obvious.

Mechanical Systems

Mechanical power steering systems use a pulley driven hydraulic pump powered by the engine to send fluid to power a pair of hydraulic cylinders, which use actuators to control the extension/retraction movement.

Electronic Systems

Electronic power steering systems are becoming more widespread, also described as drive-by-wire owing to the lack of mechanical structure. These electronic systems are becoming so advanced some have built in artificial feedback to replicate the prevailing road conditions. A torque sensor will quantify the steering input and transmit signal to the electric control unit (ECU), which amalgamates with input signals from the electronic stability control (ESC) anti-lock braking system (ABS). In turn the electric motor is powered with the force deemed appropriate by the ECU which enacts the reduction gear to convert the rotational momentum.

Which should I choose?

Electronic power steering systems will increase fuel efficiency as they negate the need for a pump, which draws power away from the engine. They also represent a weight saving over mechanical systems, making them suitable for track use. However, some feel electronic systems do not provide the direct, uninterrupted track/road surface feedback central to the drivers visceral experience and can be dull or uneventful. This mechanical versus electronic (or analogue v digital) debate is set to continue unabated.