What is suspension?
When you think of the performance of your car, do you think of torque, horsepower, and zero-to-100 acceleration?
Have you ever thought that all that power and acceleration is useless if you can’t control the car? That’s why your suspension system is crucial. In simple terms, the suspension in your car is designed to maximise the friction between your car's tyres and the surface of the road. Your suspension provides you with steering stability, improved braking response, better handling and passenger comfort.
Of course, if all roads were perfectly flat with no potholes, grooves or distortions you wouldn’t need suspension. But roads are far from perfect even when freshly laid.
This means your vehicle needs suspension to ensure its wheels remain in contact with the road.
When engineers look at vehicle dynamics they consider two key perspectives:
- The Ride - how smooth a car is on a bumpy road
- Handling - how a car safely brakes, corners and accelerates
Whilst these two characteristics are primary, there are three secondary principles engineers consider. These are:
- Road Holding - the degree to which tyres remain in contact with the road
- Road Isolation - the vehicle's ability to absorb shocks
- Cornering - handing to minimise body roll and weight transfer
Your car's suspension addresses ride, handling, holding, isolation and cornering issues.
The suspension is part of the chassis which is positioned underneath the body of the vehicle. The chassis includes the following:
- The Frame - a structural support that holds the car’s engine
- The Suspension System - this supports weight, absorbs shocks and helps tyres to remain in contact with the road
- The Steering System - this guides and directs the vehicle
- The Wheels and Tyres - these grip the road
There are three main components of the suspension system. These are the springs, shock absorbers and anti-sway bars. All three components must be in good working order for your car to drive safely on the road.
What are shock absorbers?
A shock absorber is a mechanical device that absorbs the shock impulses that travel through a moving car's wheels from the road surface. By dampening these bumps, the comfort of your journey is greatly enhanced. Without shock absorbers, you would feel every imperfection on the road when driving.
Shock absorbers work in conjunction with springs. Springs store the energy and shock absorbers dissipate the energy. It's the combination of springs and shock absorbers that contribute to the ride comfort of your car.
Not all shock absorbers are created equal. Shocks are chosen according to the loaded and unloaded weight of the vehicle and its intended purpose. A large four wheel drive vehicle will require different shock absorbers to a small family hatchback.
As the quality and performance of vehicles has improved, so has the quality and performance of shock absorbers. Many types of shock absorbers are now available.
All shock absorbers have moving parts so they will eventually wear out. However you use your vehicle – whether it's for quiet, around-town driving or rough road outback adventures – you should have your shock absorbers checked every 20,000 km.
A specialist mechanic will be able to check your shock absorbers and recommend the right ones for your vehicle and driving requirements.
How do shock absorbers work?
Shock absorbers are, simply put, small oil pumps. There is a piston inside each shock absorber which forces oil through tiny holes as the piston moves. Because the holes only allow a small amount of fluid through, the piston is slowed which in turn slows down or 'damps' spring and suspension movement.
So shock absorbers provide resistance to the movement of the springs. The energy used to compress the spring is dissipated into heat by the shocks. This conversion of kinetic energy is what helps create a comfortable ride for you and your passengers. The rocks and rolls are absorbed by the shock absorbers meaning your car drives and handles with greater reliability and comfort.
if you allow your shock absorbers to become old and ineffective, this will result in a degrading of the ride comfort and handling performance of your vehicle. You will also be at greater risk of having an accident because your ability to manoeuvre your vehicle quickly or on rough terrain will be considerably reduced.
How long do shock absorbers last?
You should have your shock absorbers checked about every 20,000 km and replaced every 80,000-100,000 km. Your specialist mechanic will be able to check and recommend the right shock absorbers for your vehicle.
Many Monroe shock absorbers are covered by a three-year/60,000 km warranty, so there's a benchmark to start from!
What are the signs of worn Shock Absorbers?
Stopping – At 50 km/h, just one worn shock absorber can increase your stopping distance by up to 2 metres.
Steering – Worn shock absorbers can cause your tyres to lose contact with the road, dramatically affecting steering.
Stability – Worn shock absorbers cause excessive sway around corners, making the car a lot less stable.
Worn shock absorbers can add as much as 20% to your stopping distance! That's the sort of fault that can be fatal and requires immediate attention.
Nose-diving and swerving
If the bonnet of your car dips when you brake or slow down, or your vehicle swerves while braking, you may have a shock absorber problem.
Uncomfortable steering wheel vibration could mean worn shock absorbers.
If your car veers in side winds, particularly when the wind isn't so strong, you could have shock absorber problems.
Shake, rattle & roll
Notice that your car 'rocks and rolls' over bumps, railway crossings or uneven surfaces? Not hugging the bends? Time to get those shock absorbers checked!
Uneven tyre wear
If your tyres are wearing unevenly, particularly if there are bald patches, odds are it's your shock absorbers.