"Suspension," when discussing cars, refers to the use of front and
rear springs to suspend a vehicle's "sprung" weight. The springs used
on today's cars and trucks are constructed in a variety of types,
shapes, sizes, rates, and capacities. Types include leaf springs,
coil springs, air springs, and torsion bars. These are used in sets
of four for each vehicle, or they may be paired off in various
combinations and are attached by several different mounting
techniques. The suspension system also includes shocks and/or struts,
and sway bars.
Back in the earliest days of automobile development, when most of the
car's weight (including the engine) was on the rear axle, steering
was a simple matter of turning a tiller that pivoted the entire front
axle. When the engine was moved to the front of the car, complex
steering systems had to evolve. The modern automobile has come a long
way since the days when "being self-propelled" was enough to satisfy
the car owner. Improvements in suspension and steering, increased
strength and durability of components, and advances in tire design
and construction have made large contributions to riding comfort and
to safe driving.
Cadillac allegedly produced the first American car to use a steering
wheel instead of a tiller.
Two of the most common steering mechanisms are the "rack and pinion"
and the standard (or recirculating-ball) systems, that can be either
manual or assisted by power. The rack and pinion was designed for
sports cars and requires too much driver muscle at low speeds to be
very useful in larger, heavier cars. However, power steering makes a
heavy car respond easily to the steering wheel, whether at highway
speeds or inching into a narrow parking place, and it is normal
equipment for large automobiles.
The suspension system has two basic functions, to keep the car's
wheels in firm contact with the road and to provide a comfortable
ride for the passengers. A lot of the system's work is done by the
springs. Under normal conditions, the springs support the body of the
car evenly by compressing and rebounding with every up-and-down
movement. This up-and-down movement, however, causes bouncing and
swaying after each bump and is very uncomfortable to the passenger.
These undesirable effects are reduced by the shock absorbers.