Car Suspension: What is it and How it Works?

If you are thinking about how comfortable your vehicle is, then it is largely attributed to the modern advances in Car Suspension systems.

However, if you think that the shocks of your car body have a simple job, then you might wanna hold that thought.

This is because the car shock absorbers or the suspension systems have other important roles to play in the optimum performance of your vehicle.

Moreover, the job of the car suspension systems is to maximize the friction between the tires and the road surface.

This, in turn, provides the steering stability with good handling.

It also helps to make sure the comfort of passengers as well.

Keep on reading to learn more about how car suspension works and its functions in detail.

Car Suspension System

If the road you are traveling on is perfectly flat, with no irregularities, your vehicle will not need car suspensions.

However, roads are far from flat and even freshly paved highways have subtle imperfections.

These can interact with the wheels of your car.

It is these perfections that apply force to the wheels.

In order to better understand the car suspension system, consider Newton’s Laws of Motion.

It states that all forces have both magnitude and direction.

Thus a bump in the road causes the wheel of your vehicle to move up and down and perpendicular to the surface of the road.

Moreover, the magnitude, of course, depends on whether the wheel is striking a bump or a tiny rock.

Either way, the car wheel will experience a vertical acceleration as it passes over an imperfection.

car suspension 2

Without the intervening structure, the vertical energy of the wheel will transfer to the frame which moves in the same direction.

In such a situation, the tires can lose contact with the road, and under the force of gravity, the tires can slam back into the road surface.

What you need to avoid such a reaction is a system that absorbs the energy of the vertically accelerated wheels.

This allows the frame and the body to ride undistributed while the tires bump in the road.

Another important thing to understand is the Vehicle Dynamics and many automobile engineers consider than from two perspectives:

  • Ride: a car’s ability to smooth out a bumpy road
  • Handling: its ability to safely accelerate, brake, and corner

Moreover, these two features comprise principles: road isolation, road holding, and cornering.

Car Suspension Parts

The suspension of the car is actually part of the chassis. It comprises all the important systems that are present beneath the body of your car.

Moreover, these systems include the following:

The Frame is the structural, load-carrying component that supports the engine and body of your vehicle.

This in turn is supported by the suspension.

Suspension systems help to support weight, absorb, and dampen shocks, and also help to maintain tire contact.


Steering Systems are the mechanism that enables you to guide and direct your vehicle.

While tires and wheel components make vehicle motion possible by way of grip and/or friction with the road.

Thus, you can say that the suspension is just one of the major systems in your vehicle.

With this in mind, let’s look at three fundamental parts of any suspension: springs, dampers, and sway bars.


The springing systems in cars today are based on one of the four basic designs. These are:

Coil Springs: The most common type of spring.

These are heavy-duty torsion bars coiled around the axis and compress and expand to absorb the motion of the wheels.

Leaf Springs: Consists of different layers of metal or leaves bound together to act as a single unit.

Moreover, leaf springs were first used on horse-drawn carriages and were also found on most American automobiles until 1985.

However, you can still see them on most trucks and heavy-duty vehicles.

Torsion Bars: These use the twisting properties of a steel bar to provide coil-spring-like performance.

They work as follows:

One end of the bar is anchored to the vehicle frame while another end is attached to a wishbone which acts as a lever. It moves perpendicular to the torsion bar.

When the wheel hits a bump, vertical motion transfers to the wishbone and through the levering action to the torsion bar.

Then the torsion bar twists along its axis to provide the spring force.

Air Springs: Consists of a cylindrical chamber of air positioned between the wheel and body of the car.

Furthermore, it also uses the compressive qualities of air to absorb wheel vibrations.

It is important to note that the Sprung Mass is the mass of the vehicle that springs support.

While the Unsprung Mass is loosely defined as the mass between the road and suspension springs.

Dampers: Shock Absorbers

Unless a dampening structure is present, your vehicle spring with extending and releases the energy it absorbs from a bump at an uncontrolled rate.

The spring will also continue to bounce at its natural frequency until all of the energy originally put into it uses up.

Moreover, a suspension that consists of springs alone will make for an extremely bouncy ride depending on the terrain, and uncontrollable car.

This is where shock absorbers come to play.

Dampers are a device that helps to control the unwanted spring motion through the process of dampening.

Furthermore, shock absorbers slow down and help to reduce the magnitude of vibratory motions by turning the kinetic energy of the suspension movement into heat energy.

shock absorbers

This is then dissipated through hydraulic fluids.

A shock absorber is an oil pump present between the frame of the car and the wheel.

The upper mount of the shock connects to the frame, i.e. sprung weight. While the lower mount connects to the axle near the wheel.

In a twin-tube design, one of the most common types of shock absorbers, the upper mount connects to the piston rod, which in turn connects to the piston.

In turn, it sits in a tube filled with hydraulic fluid.

Inner tube or pressure tube and the outer tube or reserve store excess hydraulic fluid.

When your car wheel comes in contact with a bump, it causes the spring to the coil and uncoil.

The energy of the spring then transfers to the shock absorber through the upper mount down through the piston rod and into it.

Holes perforate the piston and allow the fluid to leak. As the holes are small, only a small amount of fluid under great pressure passes through and in turn slows down the spring.

It is important to note that shock absorbers work in two cycles:

  • compression cycle
  • extension cycle

Struts and Sway Bars

Struct is another common dampening structure that mounts inside a coil spring.

Moreover, these perform two jobs:

  • a dampening functions like shock absorbers
  • structural support for the vehicle suspension

This means that struts deliver a bit more than shock absorbers, and do not support the vehicle’s weight.

However, they only control the speed at which weight transfers in a car, not the weight itself.

As shocks and structs have much to do with the handling of a car, you can consider them critical safety features.

However, worn shocks and struts can allow excessive vehicle-weight transfer from side to side and front to back.

Moreover, this reduces the ability of the tire to grip the road, as well as, handling and braking performance.

On the other hand, sway bars or anti-roll bars help along with shock absorbers or struts to give additional stability.

A sway bar is a metal rot that spans the entire axle and effectively joins each side of the suspension together.

In case the suspension at one wheel moves up and down, the sway bar transfers movement to the other wheel.

This in turn creates a more level ride and reduces vehicle sway.

Particularly, it combats the roll of a car on its suspension as it corners.

Car Suspension Types

Your vehicle has different types of suspension on the front and back.

Much is determined by whether a rigid axle binds the wheels or if the wheels are permitted to move independently.

The former arrangement is a dependent system, while the latter is an independent system.

Dependent Front Suspensions

These have a rigid front axle that connects the front wheels.

Moreover, this looks like a solid bar under the front of the car, that leaf springs and shock absorbers keep in place.

Independant Front Suspensions

In this setup, the front wheels are allowed to move independently.

The MacPherson strut combines a shock absorber and a coil spring into a single unit.

This provides a more compact and lighter suspension system that your car can use for front-wheel-drive wheels.

The double-wishbone suspension or an A-arm suspension or control-arm suspension is another common type.

It is important to note that each wishbone has two mounting positions to the frame and one at the wheel, which bears a shock absorber, and a coil spring to absorb vibrations.


Let’s discuss rear suspensions.

Dependant Rear Suspensions

When the solid axle connects the rear wheels of the car, then the suspension is pretty simple.

It is based either on a leaf spring or coil spring.

In the former design, the leaf spring clamp directly to the drive axle, the end of the spring attack directly to the frame, and the shock absorbers hold the spring to the axle.

You can also use the same basic design with coil springs.

Moreover, in this case, the spring and shock absorbers mount as signal units or as separate components.

Independent Rear Suspensions

In case both the front and back suspension are independent, all the wheels are mounted and sprung individually.

This results in ‘four-wheel independent suspension’.

Rear independent suspensions are simplified versions of the front one, though the basic principle remains the same.

Final Thoughts

With car suspension systems, your car is able to maximize the friction between the tires and the road surface. Moreover, this helps to provide steering stability with good handling and makes sure the comfort of passengers.

Car suspension is a part of the chassis that consists of all the important systems located beneath the body of the car and includes the frame, and load-carrying components which in turn are supported by the suspension.

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