how does a car's suspension work?

Despite being one of the least exciting aspects of our cars, suspensions serve an important purpose in our beloved motors. Roads are rarely (if ever) totally flat, so we need measures in place to restore stability and balance to the lower chassis.

When buying a new car, the type of suspension it has, or the quality of it, may not be very high on your list of priorities. However, it’s important to remember that without a strong suspension, your speed and flashiness is wasted.

To help demystify this topic, we’ll run through their parts, why we have them, how they work and the types of suspension available today.

what is a suspension in a car?

In short, the suspension’s main job is to smoothen out the riding experience, restore balance to the car and increase the level of friction between the tyres and tarmac.

Rather than just one component, the suspension is composed of multiple parts. Your car’s tyres, air pressure, shock absorbers and springs all come together to form the suspension, with the bulk of the work taking place between each row of wheels.

how do car suspensions work?

Suspensions work off a basic engineering principle of evenly distributing force across your car’s lower chassis. As tyres turn and encounter rough terrain, they can start to violently vibrate in unpredictable ways. The suspension’s job is to smoothen out those vibrations, making the driver feel as though they are in one continuous stream of motion.

It doesn’t always work out that way; suspensions can only prevent so much. However, they are an absolute necessity for cars both old and new.

suspension parts list

While all kinds of suspensions are different, there are a few parts they all have in common:

damper (shock absorber)

Dampers, or shock absorbers, are a set of pump-like devices that help control sudden impact and movements of the car’s suspension. Sitting closest to the car’s wheel, the dampers absorb kinetic energy from the wheel and convert it into energy. Because of this, dampers are filled with oil to dissipate the heat away from your car.

coils (springs)

Coils, or springs, have a similar job to dampers in the sense that they absorb sudden shocks of motion depending on the vehicle load. These are usually found wrapped around dampers, but they do play a bit more of a specific role in the suspension. Coils are mostly there to ensure your car doesn’t topple over when weight is shifted from one side to the other.

ball joint

In a suspension, the ball joint is what sits between the wheels and the main suspension. Despite their small size, their job is equally as important as the rest of the system. Their domed top helps ensure smooth movement across the entire suspension, much like the bones that make up human shoulders. 

knuckle arm

The knuckle arm completes the connection between the wheels and the suspension. It contains the main wheel hub and sits atop the ball joint. The knuckle is the very last part of the entire steering mechanism, and thus usually completes the suspension system.

types of suspension

With so many different types of car available today, all in varying sizes and physical strength, there are now several types of suspension in cars to choose from:

multi-link

Muti-link suspensions are characterised by their having multiple points connecting the car frame and wheel assembly. These suspensions are usually more robust than they need to be, which is why they’re usually found on off-road vehicles. The multi-link system is often excluded to the rear wheels, as these are usually what restore balance in the event of a sharp turn or jolt of speed.

rigid axle

Rigid axle suspensions are one of the most simple designs on the market. This is due to them being one of the first types found on road cars, dating back to when popularity for such vehicles was beginning to rise. As their name implies, rigid axle suspensions connect wheels via a single, solid shaft that does not adjust flexibly.

If one wheel encounters a bump or moves in an irregular way, the other side moves along with it. This can cause a loss of traction. However, rigid axle suspensions do offer greater degrees of horizontal wheel travel - a particular benefit enjoyed by pick-up trucks or other heavy-lifting vehicles.

independent

In an independent suspension system, each wheel is attached to the vehicle frame via a series of control arms, which allow it to move up and down. The control arms are connected to the frame at one end and the wheel hub at the other, allowing the wheel to pivot as it moves.

macPherson suspension

A Macpherson suspension is another type of independent suspension. Its strut accomplishes the same goals as a steering rod, thanks to a combination of the shock absorber and spring, while also featuring a control arm underneath. The strut is attached to the vehicle's frame at the top and to the wheel hub at the bottom. This allows the wheel to freely move around while the body stays still.

The lower control arm helps to guide the wheel as it moves and maintains its camber (angle) in relation to the road. As the wheel hits a bump, the strut compresses and the control arm pivots, absorbing the impact.

The name is derived from the inventor of the system, Earle S. MacPherson, a mechanical engineer at Chevrolet in 1945.

leaf springs

Leaf spring suspensions are commonly found in heavy-duty vehicles like trucks and lorries. They offer a stiff suspension thanks to an assortment of flat metal springs (leaf springs).

In a rigid leaf spring suspension system, the leaf springs are attached to the vehicle's frame at one end and the axles at the other. As the vehicle moves, the leaf springs compress and expand, allowing the wheels to move up and down. This helps them absorb impacts without disturbing the ride experience.

The leaf springs are designed to be rigid, meaning they do not flex or bend, which provides a stiff and stable ride.

trailing arms

Trailing arm suspensions are usually found on rear-wheel drive cars. They operate via a pair of control arms (trailing arms). These arms support the weight of the vehicle, allowing the wheels to articulate as they encounter bumps in the road.

double wishbone

Double wishbone suspensions are one of two types of suspension usually found on high performance vehicles like rally cars and sport trims.

Double wishbone suspensions are named as such due to the control arms resemblance to wishbones. They are attached to the car’s frame and wheel hubs on opposing ends. This double joint allows the wheels to move vertically as the vehicle moves along a road, reducing the likelihood of jumps and bumps while on a journey.

air

Air suspensions are the most advanced type of suspension, doing away with traditional control arm mechanisms to connect the wheel and frame. Instead, air suspensions use bags filled with air (bellows) in between each part of the control arms to complete the connection. While driving, these air bags compress and expand in a much smoother way than a mechanical mechanism.

Air suspensions are also usually able to be adjusted on the fly by the driver. If you’ve ever driven next to a truck and heard a sudden gush of air when the driver comes to a full stop, that’s the sound of an air suspension.

find used cars with modern suspensions today

A car's suspension system plays a crucial role in the handling, stability, and comfort of a vehicle. Understanding how a suspension works and the different types of systems available can be helpful when shopping for used cars, as it can provide insight into the overall performance and condition of the vehicle.

Whether you're looking for a sports car with a double wishbone suspension or a luxury vehicle with an air suspension, you might be able to find it at findandfundmycar.com.