All about suspension

Posted by: Cal on 13/12/2013

Category: Tyre Information

Many of us know the basics of how our cars operate and how to maintain them, but the inner workings of motor vehicles can leave some of us scratching our heads.

Start your motor vehicle education off with this in-depth look into your car's suspension system.

What it does

Your car's suspension essentially absorbs friction from the road before it travels up to affect the body of your vehicle. In essence, it allows car tyres to travel along the road easily by maximising friction between tyre and surface, as well as providing steering stability.

If all roads were flat and without imperfections, we wouldn't need suspension in our cars. However, roads everywhere are filled with potholes, bumps and other irregularities that drivers must navigate on a daily basis.

Driving over imperfections applies force to the wheels, causing them to move up and down. Without a suspension system, all of this energy would be transferred to the body of the car, moving it in the same direction. This could cause all or some of the wheels to leave the ground before slamming back down onto the road, which would understandably be both uncomfortable and dangerous.

The suspension system simply absorbs the wheels' energy, leaving the body of the car (and therefore its passengers) undisturbed as the wheels travel over irregularities. It also allows vehicles to turn corners without rolling over as it shifts the centre of gravity so the car can maintain balance.

What are the components?

The key components of a car's suspension include springs, shock absorbers, struts and anti-sway bars.

Springs can come in four varieties, but the most common type is coil. These springs consist of heavy-duty torsion bars wound around an axis. They compress and expand, absorbing the motion of the vehicle's wheels.

Shock absorbers control spring motion to slow down and reduce vibrations by turning kinetic energy into heat energy that is dissipated through hydraulic fluid. Modern shock absorbers are velocity-sensitive, enabling them to adjust to different road conditions and control unwanted motions that occur in cars.

Struts are shock absorbers mounted inside coil springs, which provide structural support for the vehicle's suspension. Shock absorbers cannot support vehicle weight like struts.

Anti-sway bars are used with shock absorbers to give a moving car stability. A bar consists of a metal rod that spans the axle and joins each side together, transferring movement so it's even on both sides of the car.