How Your Car's Suspension Works
A simple guide to how car suspension works, and how to spot common problems.
What does car suspension do?
A car's suspension system absorbs the bumps, holes and imperfections found on every road, ensuring a smoother ride for passengers and improving the car's ability to safely accelerate, brake and corner. Because the suspension plays such an important role in the handling of a car, its components are considered critical safety features.
What are the components of car suspension?
The frame, steering, tyres and wheels all play their part in providing the overall stability and suspension of a vehicle, but the actual suspension essentially comprises springs and dampers.
The most common kind of spring is a coil spring. Most cars have four coil springs, one at each corner of the car, which compress and expand to absorb any vertical movement in the wheels.
Although springs are great at absorbing energy, they're not so good at dissipating it. This is where dampers come in - they dampen the motion through the spring so that the car doesn't keep bouncing.
The two common types of damper on modern vehicles are shock absorbers and struts.
Shock absorbers dissipate the energy in the spring through hydraulic fluid.
Struts are basically a shock absorber in a coil spring - they support the vehicle's weight as well as dampening the energy in the spring.
How to recognise common suspension problems
The traditional 'bounce test' which tests a vehicle's suspension was (somewhat controversially) removed from the MOT test in 2014, so it's more important than ever for drivers to watch out for signs of problems with their suspension.
It's often difficult to spot problems, but one tell-tale sign is if one corner of the car is lower than the others when parked on flat ground. This would be due to one of the springs sagging or breaking. If one of your springs is wearing out you might also notice a knocking sound as you drive, or poor handling when cornering.
When shock absorbers wear out you'll notice that the car feels more bouncy as you drive over bumps, and the fluid held in the shock absorbers may start to leak. Worn shock absorbers can increase your stopping distance by up to 20%, so driving with them can be very dangerous.
If you think there may be a problem with your suspension, or would simply like peace of mind, you can book a Free Suspension Check at any one of our autocentres.