Shock absorbers are essential for passenger comfort and vehicle handling, but their importance can easily be overlooked. Worn, failing, or mismatched shock absorbers severely compromise the braking and handling performance of a vehicle and put vehicle occupants and other road users at risk.
Sometimes called dampers, shock absorbers are perhaps the hardest working components of a vehicle's suspension system. They are designed to control the movement of a vehicle's springs to ensure that the tyres maintain contact with the road surface. Without the 'damping' action of good shock absorbers, the springs will allow the wheels to bounce - like a basketball - when contacting undulations in the road.
A bouncing ball spends much of its time in the air. This is also true of a bouncing tyre. Logically however, tyres must be held firmly in contact with the road for safe braking and cornering. Faulty shockers can cause a vehicle to run suddenly and unexpectedly wide should it strike undulations or broken bitumen mid-corner. Faulty shockers can also cause wheels to skitter on the road surface when braking and can dramatically increase braking distances.
In this way, the condition of a vehicle's shock absorbers are crucial to its safe operation and the safety of its occupants.
A shock absorber is an oil-filled tube that contains a piston. It resists the movement of the suspension springs by restricting the flow of oil inside it through a number of control valves. The oil prohibits the free movement of the piston, preventing uncontrolled suspension movement.
Some shock absorbers contain a high-pressure gas instead of oil, and are generally more expensive but can offer better performance.
The front suspension system in many newer vehicles is designed with a built-in shock absorber - called a 'MacPherson Strut' - which has the benefit of making the suspension more compact and lighter in weight.
Shockers generally wear out gradually, and, with gradual change, things affecting the performance of a car can pass unnoticed. Some drivers may not be aware that their shockers are not up to scratch. That's why it's important to have the suspension system checked regularly during servicing by a TACC Accredited Repairer.
You can however do some simple checks yourself to get some indication of the condition of the shockers.
Often, suspension problems are indicated through the steering system. If the steering wheel shakes excessively after hitting a bump or pothole when driving, or if the car seems unstable over rough or unsealed roads, the shock absorbers could be worn.
The reaction of a vehicle when braking can also point to worn shock absorbers. Sometimes the vehicle will 'nosedive' excessively, where the front of the vehicle dips under braking, if the shockers need replacing. The vehicle will take a greater distance to stop, and may swerve to one side if the brakes are applied suddenly.
If you suspect there is a problem with your vehicle's shock absorbers, check the tyres. Uneven wear or bald patches are a good indication that something is wrong.
Also look at the side of the shock absorber tube. If there is any oil leaking, the shock absorber will be unable to perform effectively.
The type of shock absorber best-suited to your vehicle depends on the conditions you predominantly drive in (whether, for example, you drive predominantly on highways or over rough roads), the load your vehicle carries or tows, the type of vehicle and your budget.
There are a variety of shock absorbers available on the market, and a TACC Accredited Repairer or a TACC Accredited Steering and Suspension Specialist can advise you on the most suitable type for your vehicle.
Issued by TACC, the Tasmnian Automobile Chamber of Commerce.