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All cars are steered by turning the front wheels in the required direction and allowing the rear wheels to follow. There would be several disadvantages in trying to steer a car by its rear wheels, the main one being that the car would be directionally unstable.
On a bicycle, the steering is controlled directly by the handlebars. But in a car, the driver would not be strong enough to control the front wheels if they were connected directly to the steering wheel. So the steering must include a gearbox, and sometimes power assistance, to multiply the driver’s effort.
Major requirements in any steering mechanism are that it should be precise and easy to handle, and that the front wheels should have a tendency to return to the straight-ahead position after a turn. The steering must not ‘kick back’ from road shocks, although there must be some degree of reaction, or ‘feedback’, from the road to the driver.
The steering column encloses and supports the steering shaft and some cars have an adjustable steering column. The top part — with the steering wheel — can be moved up and down in telescopic fashion and, in some cases, can be tilted at an angle to suit the driver’s height and driving position.
Considerable research has been carried out in recent years to safeguard the driver against injuries inflicted by the steering wheel (or column) when the car is involved in a front-end collision. The steering column can be designed to collapse on impact. The tubular column is made of an ‘expanded-metal’ grid so that, although strong in twist, it collapses and absorbs energy if compressed lengthwise.
While the steering wheel in older cars was ‘dished’ and provided with a large boss and wide spokes to spread the load of impact over the driver’s chest, modern steering wheels are made from soft polyurethane material.
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