What Are Shock Absorbers?
Ellie Dyer-Brown, 19 days ago
5 min read
- Suspension
- How it works
FixMyCar explains what shock absorbers are and what they do.
Shock absorbers (also known as shocks or dampers) are a crucial part of a car’s suspension system, responsible for reducing the impact of potholes and other bumps in the road. This guide explains how they work, how long they last and what happens when they wear out.
Contents
How long do shock absorbers last?
Symptoms of faulty shock absorbers
What do shock absorbers do?
Shock absorbers have two main roles. They:
Control the movement of the suspension to lessen the impact of bumps in the road.
Keep the tyres in contact with the ground at all times.
By doing this, they also reduce tyre wear and improve a car’s handling.
How do shock absorbers work?
Shock absorbers are cylindrical, hydraulic components that work like pumps. They take the suspension's kinetic (movement) energy and convert it into thermal (heat) energy, which is dispersed into the atmosphere through heat exchange.
In each shock absorber, a piston is attached to a piston rod, working against the hydraulic fluid in the pressure tube. The fluid is forced through tiny holes into the piston when the suspension moves up and down. Because these holes are so small, they slow the flow of the liquid, which in turn slows down the spring and suspension movement, making jolts from the road less harsh.
Types of shock absorbers
All shock absorbers do the same thing, but there are different types to suit different systems. Telescopic shocks are found in conventional suspension systems. They consist of an oil-filled cylinder and are relatively cheap to replace.
Below are some variations of hydraulic shocks.
Monotube shocks
These shock absorbers contain a single tube that houses the fluid, piston and gas. They contain more oil and have a larger piston than twin-tube shocks, which allows for improved heat dissipation and a more controlled damping effect.
Because they use high-pressure gas, they often provide a stiffer ride and are more expensive to produce.
Twin-tube shocks
As the name suggests, twin-tube shocks use two cylinders. The inner one contains the piston and shaft, while the other acts as a fluid reservoir and contains low-pressure gas to absorb vibrations. A valve controls the liquid’s movement between the cylinders.
Twin-tube shocks are more affordable than their single-tube counterparts, but they are more prone to oil foaming, which reduces their effectiveness.
Remote reservoir shocks
Remote reservoir shock absorbers are typically found in high-performance and off-road vehicles. They have an advanced design featuring an external reservoir and hose that connects the main cylinder to the oil tank. This increases the shock’s oil capacity, which allows it to dissipate heat more effectively.
How long do shock absorbers last?
Many factors can influence the lifespan of shock absorbers, including your driving style and the types of roads you use, which makes it difficult to estimate how long they will last accurately. Many manufacturers say you will get five to ten years from them before they need replacing.
Symptoms of faulty shock absorbers
It’s usually easy to tell when your shock absorbers are worn out because you will notice symptoms such as:
Uneven tyre wear - bald patches may appear on some parts of your tyres.
A bumpy ride - your car may bounce more after hitting a speed bump or pothole.
Nose diving - when you brake, the front of your vehicle might dip, often caused by fluid leaking from the shocks.
Tilting to one side - you might notice this even when your car is stationary.
A visible leak - shock absorbers often leak fluid when they’re worn out.
Increased stopping distance - your vehicle will be less responsive when you brake if the shocks are worn. Here are five other brake problems you shouldn’t ignore.
How many shock absorbers does a car have?
Each wheel on a car has either a shock absorber or a strut, so there are four in total. You can find out how struts are different in our guide to suspension.
How much are shock absorbers?
Shocks can cost anywhere between £40 and £200 each. It depends on the make and model of your vehicle, the type of shock absorber you need, and the quality of the part.
Shock absorber replacement cost
According to FixMyCar’s data, the average price of replacing a front shock absorber is £347.77, and replacing the rear shocks costs £277.42.
Why shock absorbers should be replaced in pairs
When your front right shock absorber goes, you should replace the left one simultaneously, even if it hasn’t sustained the same level of wear. There’s an important reason for this. For your suspension system to work efficiently, pairs of shocks must be in roughly equivalent working condition.
Pairing a new shock with an older one will likely create uneven damping across the axle, putting the new part under more pressure and leading to premature wear.
Worried about the condition of your shocks? Whether you want to get your suspension system checked or book a shock absorber repair, FixMyCar can help you find the right garage at the right price.
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Written by Ellie
Ellie is FixMyCar's Content Writer. She has over three years of experience writing about cars and regularly collaborates with automotive experts to provide trustworthy advice for drivers that is easy understand. Her work has been featured in Yahoo! Finance, iNews, The Daily Express and The Sun. She has a BA in English literature and an MA in creative writing from Durham University. Outside of work, Ellie follows F1 and eagerly awaits Ferrari's next era of dominance in the sport. She drives a Suzuki Swift.