Types of suspension: adaptive suspension explained

You may not have given much thought to your car’s suspension, but it plays an important role in making your car comfortable and safe. Suspension systems usually consist of a series of springs, shock absorbers and linkages that optimise the comfort and handling of your car. 

The suspension soaks up bumps in the road to minimise jarring for the occupants and stop the car from being thrown off course if it hits a pothole. It also helps to keep the tyres in contact with the road to ensure the car retains grip at higher speeds and when cornering.

This is why engineering and fine-tuning a car’s suspension system is a complex balancing act to achieve the best compromise between compliance and grip. It’s also what sportier models are often firmer; here, more emphasis is placed on grip and stability than delivering a supple ride over broken tarmac.

There are two main types of suspension: dependent and independent, but you only really need to know about independent suspension because this is the type fitted to all modern cars; only commercial vehicles and HGVs have dependent set-ups. 

A dependent suspension system acts on the left and right wheels of the car at the same time, while an independent suspension system controls the forces on all four wheels independently. 

What’s in a car suspension system? 

Springs 

Most modern car suspension systems have a spring above each wheel, which absorbs energy when the wheel hits a bump. 

Shock absorbers

Again, there’s one of these for each wheel, and they either sit close to the coil spring or inside it – in which case they’re known as struts. The most common strut suspension is the MacPherson strut, which is widely used on the front ends of many different cars. It’s named after its inventor, Earl MacPherson. 

Shock absorbers contain a piston and hydraulic fluid that help the car recover from hitting a pothole by releasing the energy that goes into the spring in a controlled way. When the car hits a pothole the piston is pushed into the fluid, forcing it in one direction, then, when the fluid changes direction it slowly goes back to its original position while the piston releases gently. 

Anti-roll bar

This is usually a metal bar that connects the right and left wheels of your car in the lower part of the suspension. It enhances the car’s overall stability and reduces body roll during cornering. 

When your car turns, the weight shifts to one side, causing the body to roll or lean towards that side; the anti-roll bar works against this by transferring some of the suspension movement from one side of your car to the other. It helps the car maintain contact with the road and improves grip and handling.

What is adaptive suspension? 

Adaptive suspension takes the technology a step further by introducing electronic shock absorbers or damper controls that enable the driver to select different settings. These are usually oriented towards comfort, normal and sportiness and, each provides a different blend of comfort and handling. Typically comfort will provide the smoothest ride and sport will have a harsher ride but better handling.  

There are three types of adaptive suspension: valve-actuated, electromagnetic and air suspension. 

Valve-actuated suspension

The most common is valve-actuated adaptive suspension. This uses an electronically-controlled valve inside the shock absorber to control the amount of fluid flowing through the piston; restricting it makes the suspension firmer and opening it up softens it up. Many Volkswagen models, including the Tiguan, Touran and T-Roc have this type of suspension, and the brand name for it is Dynamic Chassis Control. 

Electromagnetic suspension

Instead of conventional damper oil, vehicles fitted with this type of suspension have shock absorbers filled with magnetorheological fluid, which can change its viscosity by sending a metallic charge through the liquid. 

When you select a firmer setting for the suspension, a magnetic charge passes through the shock absorber increasing the density of the metallic particles in the fluid and creates more resistance on the piston. If you pick a softer ride setting the magnetic charge drops, reducing the load on the piston. 

This type of system is fitted to many Audi models including the previous generation A3, R8 and TT, on which it’s called Magnetic Ride Control.

Air suspension

Cars with this type of suspension have shock absorbers, but use airbags instead of springs. This is the most versatile type of adaptive suspension because both the resistance in the shock absorber and the pressure in the airbag can be electronically controlled. 

As well as varying the firmness of the suspension, it can often raise or lower the ride height, which is why it’s standard on top-spec versions of many premium SUV models, such as the Audi Q6 e-tron, BMW iX, Land Rover Defender and Range Rover. 

Other types of adaptive suspension

Citroen has long been an innovator when it comes to suspension, perhaps most notably the hydropneumatic self-levelling suspension of the 1950s DS.  

The latest Citroen DS 9 luxury saloon comes with Active Scan Suspension, which uses a camera at the top of the windscreen to scan the road in front and prime the suspension for upcoming imperfections. It works well at motorway speeds, but isn’t as effective on urban streets. 

The Polestar 2 luxury electric saloon can be had with Öhlins adjustable shock absorbers, which have three settings: Nominal, Track and Comfort. While they do make the car feel more agile through corners, they need to be adjusted manually, by getting under the car and twisting a dial on the shock absorber. Many owners will ask their local Polestar dealer to do it.

Adaptive suspension vs air suspension, which is best? 

The main advantage of air suspension over other types of adaptive suspension is that it offers the most glassy ride over poor quality roads and potholes. It also has the advantage that you can lower or raise the car’s body shell at the touch of a button, making it easier to get into a tall SUV or load heavy items into the boot. 

The downside is the cost, because air suspension isn’t available on many mainstream cars, so you may have to opt for a premium model to get it. Even then, it’s often an expensive optional extra on lower spec models. 

Should I buy a car with adaptive suspension? 

If you often cover long distances, or are particularly bothered by the instructions caused by uneven road surfaces, it’s worth finding a model with adaptive suspension. Similarly, it’s a feature that’s popular with drivers of sports cars and performance cars because the sport setting improves grip and handling, but still allows for a softer ride on long-distance drives. 

However, not all adaptive suspension systems provide a significant change in ride and handling, so if you’re unsure about whether or not you will benefit from it, it’s worth having a test drive in a car fitted with it before you buy. Our car reviews cover this in detail.

Which models come with adaptive suspension? 

Most car brands offer adaptive suspension on many of the models in their line-up, although it may be a cost option on lower spec versions. Confusingly, many car makers use different names for their adaptive suspension systems. For example, BMW’s is called Adaptive M Suspension, Ford’s is called Continuously Controlled Damping and Mercedes has Active Body Control. 

How can you tell if your car’s suspension is broken? 

If your car’s suspension system is broken or worn, the tell-tale signs include jarring when driving over potholes, the car pulling to one side, or one corner of the bodywork sitting lower than the rest. To test your car's suspension, press down on a front wing - if the car bounces back gently it's fine, but if it continues to bounce up and down or makes any nasty clunking noises, it's best to get the suspension checked out. 

When a shock absorber begins to wear out, fluid can leak from it making it less effective. This affects the car’s ride and handling, and accelerates tyre wear. You may notice oil leaks on your driveway or under the car.

About the report author

Claire Evans has been a motoring journalist for more than 30 years, much of that time spent specialising in consumer issues. She was a troubleshooting advice columnist for Carweek magazine in the 1990s, helping car owners with faulty cars get the right level of reparation from car makers.

She also spent six years working on motoring content for Which?, and it is here she oversaw the running of the charity's annual used car reliability survey.

Claire launched the What Car? Reliability Survey in 2017, and since then has helped thousands of buyers choose the most reliable new cars and SUVs, as well as the most dependable used cars. The survey data is also shared with car makers, who use it to find out more about issues with models and the areas where they could look provide better customer service.

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