How Stuff Works

Classic car steering

Wondering how something as simple as a steering wheel could possibly feature as a part the How Stuff Works series? Then read on, as beyond the basic function of the component, a lot of technology has gone into their design over the years.

Early cars took their lead from a nautical direction, using a tiller. The system worked to a basic degree, allowing one hand free with which to signal and gesticulate. However, this was not ideal from the aspects of control and safety, so things progressed towards a wheel, arguably also nautical, but without handles radiating from the rim.

The wheel encouraged two-handed control, giving drivers a firmer grasp of the situation – car cockpits began to take on the classic appearance that we know and love today.

At first, heavy cast wheels with wooden rims were common, but gradually, with the migration of steering control from the horizontal towards a more vertical plane, and the re-siting of dials and gauges within the driver’s eyeline, the need for a slender, yet strong solution became necessary.

Cast centre bosses became almost ubiquitous and with the advent of Bakelite-covered, steel wire spokes and rims in the 1920s, the scene was set for the following half-century. Sporting models were often fitted with lightweight steel or aluminium spokes, with riveted wooden rims, adding a touch of luxury.

As safety and ergonomics began to become areas of concern, thought was given to placing some controls at the centre of the wheel. Earlier cars had ignition advance/retard and throttle controls mounted on a nonrevolving centre boss. The clever bit was the feeding of control rods down the middle of the rotating column, through a tube clamped at the base of the steering box and out to their respective connections.

Gradually, electrical items, such as horn push and indicator controls, found their way to the central mounts, with wiring routed through the central tube, but unarticulated steering columns were on their way out, once again as a factor of rising safety concerns. While indicators migrated to column stalks, there was no better place for a horn push than the centre of the steering wheel and so sprung carbon contacts were held against a copper ring, attached to the now emergent column control binnacles. This allowed jointed steering columns to be developed, giving greater flexibility when designing directional control systems and offering increased options in steering position adjustment.

Padded rims, at first leatherclad, emerged in post-war years and this soft-feel was eventually economically translated into the plastic-clad moulded foam wheels of the Seventies onwards. These also offered improved driver protection in the event of an impact.

From the Nineties onwards, steering wheel centres cleverly concealed supplemental restraint system (SRS) airbags, designed to inflate in the event of a collision. It also accommodated numerous additional electronic controls, the latter enabled by development of the technology first put into use for the humble horn push on jointed steering columns.

Although the wheel itself has remained a constant feature and takes little explanation, it is all of that innovation that has allowed it to develop into part of the ergonomic environment that we drivers enjoy today.

’Innovation has led to the ergonomic environment we all enjoy in cars today’