How Car Suspension Works

This suspension uses a separate spring and shock absorber.

A suspension suspends and supports the chassis. In addition to holding the car off the ground, the suspension is responsible for controlling body and wheel movement during cornering and over imperfections in the road.

Basic Parts

All suspensions are comprised of 5 basic components: wheels, axle/hub, control arms, springs and shock absorbers.

Major Hardware

The wheel-tire package rides on a central hub or axle, depending on whether the car uses independent suspension (hub) or a solid axle. The hub/axle connects to the chassis via a set of control arms. The control arms dictate the direction that the wheels/axle will move when it goes up or down.

Dynamic Controls

The suspension's main springs sit between one of the control arms and the chassis to bear the weight of the body. Shock absorbers are liquid or gas filled tubes that slow the wheel's movement up and down. Without shock absorbers, the spring and wheel's inertia would cause the spring to overextend and bounce back (oscillate) whenever the wheel encounters a bump, just like a rubber ball hitting a sidewalk.

Struts

Many cars use MacPherson strut suspensions. A strut is a combination upper control arm/coil spring/shock absorber package that helps reduce weight, complexity and cost of manufacture.

References

• Edmunds: uspension Basics I: Shake, Rattle and Roll
• Rover SD1: Suspension Basics
• Cannondale: Suspension Basics