What are shock absorbers?
Shock absorbers have two key roles: soaking up and smoothing out bumps on the road surface and ensuring that the vehicle’s tyres retain a constant contact with the surface. There are a few different types of shock absorbers, but all do essentially the same thing, and each type depends on the suspension setup of the vehicle.
What do shock absorbers do on a car?
Inside the
shock absorber there's a piston that moves inside a tube that is filled with oil. As the piston moves, the oil is forced through tiny holes and valves within the piston, precisely controlling the amount of resistance. They help to regulate the rate at which the suspension moves as it absorbs and rebounds from bumps in the road. This action can cover a spectrum from large potholes to small ripples along the surface.
Where are shock absorbers on a car?
You’ll usually find your shock absorbers mounted in and around the main suspension components of your vehicle. These will look like a long vertical tube and will either be positioned vertically or diagonally close to the suspension spring.
How often should shock absorbers be replaced?
The lifespan of a shock absorber can vary slightly between manufacturers, and the severity of the roads upon which it has been subject to will also have an effect on its functionality. As a general rule, most modern shock absorbers should be at least checked every 30,000 kilometres and replaced every 80,000km. As this can be a labour intensive job, depending on the vehicle, it can be more cost effective to replace a set each time. Doing this will ensure more even wear over the lifespan of the units, too.
Click here if you need new shock absorbers for your car
Tell-tale signs that your shock absorbers need replacing can include loud knocks or rattles when going over bumps. Another sign is uneven wear on your tyres, which can be caused by the tyres not having an even amount of contact with the road surface.
What causes shock absorbers to leak?
In most cases, shock absorbers fail due to simple wear and tear, but the types of surfaces that the vehicle drives on can also have an effect. For example, if the surface is particularly bad with lots of severe potholes then this could reduce the lifespan of the parts. Over time the seals can become weakened or tear causing the fluid inside to begin to leak out. As this fluid leaks out, the ability of the shock to absorb energy and function correctly diminishes. One way to identify a failing unit is the presence of a damp or wet area around the shock absorber, which can be easier to spot when the unit is dirty. However, these seals can also see their lifespan reduced if they are constantly subject to adverse conditions like grit, sand or mud. Small particles of dirt can make their way into the seals and accelerate the wear process, so it’s a good idea to clean in and around the wheel arches regularly.
Are shock absorbers covered under warranty?
It is rare for a car manufacturer to include shock absorbers as part of its warranty cover as these are commonly considered to be a ‘wear and tear’ item. Shock absorbers can be subject to especially rough abuse over a short period. If a shock absorber were to fail on a relatively new vehicle with little mileage and no signs of ill-treatment, a car manufacturer might consider replacing the item as a goodwill gesture. However, this would be a rare occurrence.
What shock absorbers do I need?
If you are just replacing your worn shocks like for like, then you need to ensure that you are choosing the correct type that is the recommended unit for your make and model of car. These parts can vary whether your car is a hatchback or estate, or perhaps a performance version, such as a Volkswagen Golf GTI. One other thing to remember when ordering replacements is that these items are also side-specific, meaning the left unit is not always identical to the right unit, so make sure you are selecting the correct ones.
How to choose shock absorbers
Choosing which shock absorbers to fit on your car depends firstly on the type of car that it is and then what your normal driving consists of concerning surfaces and loads. For example, if it is your everyday car that you commute in, then sticking strictly to the manufacturer’s recommended units is best and should result is a comfortable ride. However, if you have a track car that you use primarily on a circuit, then you may wish to have upgraded units fitted that allow for greater adjustability and may be stiffer thus giving a more performance-orientated feel. These may also require further changes to the rest of the suspension setup.
Which shock absorbers are best?
Generally speaking, choosing well-known brands and sticking to the shock absorbers that the manufacturer recommends for your vehicle is the best course of action to take. As some car models get older, parts like shock absorbers can also sometimes be made by spurious parts suppliers. These can often be made to the same design and will work in the same way. But you must also be wary to avoid buying cheaper imitation parts that may not always adhere to the same manufacturing standards.
How to adjust shock absorbers
Not all shock absorbers are adjustable; more often it is aftermarket units or those fitted to more performance-orientated vehicles that offer any adjustment. If you do decide to adjust them, it is first a good idea to record the settings of the units before you make any changes; that way if you aren’t happy, it is easy to revert to their original position.
There are two parameters of adjustment, compression and rebound. Compression determines how quickly the shock moves to absorb the impact, or to phrase it another way, how stiff it will feel. The rebound is, as you may guess, how quickly the shock absorber returns to its uncompressed state. A faster rate of rebound can make it feel springier, but this isn’t always the ideal solution. On the other hand, a slower rebound may have adverse effects if there is a secondary bump in quick succession, as the absorber is still partially compressed thus reducing its ability to soak up the impact. If you do choose to adjust your shock absorbers, doing so in minor increments until you find your ideal setting is usually the best course of action to take.
Shock absorber FAQ's
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