Car suspension how does it work

In a suspension system, various components work together to absorb bumps in the road, dispersing energy for a balanced ride.

Although there are a different kinds of suspensions, the major components in a suspension system are equipped with some type of shock absorbers, springs and struts.

How these major components work together, include:. Without these components in good working condition, your driving experience will get less comfortable, more dangerous and can potentially lead to other car problems such as alignment, tire wear, steering, and braking problems.

The suspension system, even with all the components mentioned above, remains incomplete without the frame. The frame forms the skeleton onto which the weight of the car and its load is supported. It also offers a certain degree of support to the engine. Note that other suspension structures also provide support to the vehicle. We have another article covering the various types of suspension systems and how they differ from each other.

For suspension replacement parts , visit our website and find the most reliable auto parts sellers in Australia and the latest updates on the auto industry! Sam O. How Does a Car Suspension Work? Educational Dec 23rd, The suspension system is an integral part of any car. Parts and their Functions The modern suspension system comes in various types, and each type consists of many pieces and structures.

Springs The springs absorb the shock forces when your wheels go over bumpy surfaces or potholes. Springing systems take many designs, but the common ones are: Coil springs — Of all the types, this is the most common. It consists of heavy-duty torsional coils on the axis. They absorb the impact through compression and resultant expansion. The stacking ensures they work as a single unit. Torsion bars — Steel bars can twist to a certain degree resulting in a coil-spring-like reaction, and torsion bars make use of this property.

Anchored onto the ends of these bars are the vehicle frame and wishbone. The wishbone moves perpendicularly relative to the torsion bar. When you hit a bump while driving, vertical motion is generated. It is transferred to the wishbone, which is then passed on to the torsion bars via levering action. The torsion bars react by twisting along their axis, and this reaction provides the spring force. Air springs — Air springs use a cylindrical air chamber, which is located between the wheels and the body.

The compressive quality of air absorbs any impact from the wheels. Shock Absorbers You can think of a shock absorber as an oil pump positioned in between the car frame and the wheels. Types of Shock Absorbers Shock absorbers can be any of the following: Telescopic — applied in both front and rear suspensions Strut type Spring seat shocks — combines both telescopic and strut features 3. These are leaf springs. When the car hits a bump, the suspension moves, causing the bar to twist and absorb the energy.

A spring is good at compressing and absorbing energy but not so good at releasing it, when it tends to rebound uncontrollably. In a car, that uncontrolled action would ruin its ride and handling. This is where the shock absorber, or damper, comes in. It looks like a thick, stubby bicycle pump. Most are in two sections. The top section is called the outer tube. The lower half, called the reserve tube, is bolted to the axle, or to the structure that carries the suspension system.

It is filled with hydraulic fluid. As the car goes over a bump, the axle rises, compressing the spring and forcing the piston to move down into the fluid. This motion forces the fluid upwards and through small holes in the piston. However, the next moment, the piston is rising back up as the spring rebounds, at which point the fluid changes direction and returns to the reserve tube.

Let's look at the parts of a typical suspension, working from the bigger picture of the chassis down to the individual components that make up the suspension proper. These systems include:. With this big-picture overview in mind, it's time to look at the three fundamental components of any suspension: springs, dampers and sway bars.

Based on where springs are located on a car — i. The sprung mass is the mass of the vehicle supported on the springs, while the unsprung mass is loosely defined as the mass between the road and the suspension springs. The stiffness of the springs affects how the sprung mass responds while the car is being driven. Loosely sprung cars, such as luxury cars think Mercedes-Benz C-Class , can swallow bumps and provide a super-smooth ride; however, such a car is prone to dive and squat during braking and acceleration and tends to experience body sway or roll during cornering.

Tightly sprung cars, such as sports cars think Mazda Miata MX-5 , are less forgiving on bumpy roads, but they minimize body motion well, which means they can be driven aggressively, even around corners.

So, while springs by themselves seem like simple devices, designing and implementing them on a car to balance passenger comfort with handling is a complex task.

And to make matters more complex, springs alone can't provide a perfectly smooth ride. Because springs are great at absorbing energy, but not so good at dissipating it. Other structures, known as dampers , are required to do this. Unless a dampening structure is present, a car spring will extend and release the energy it absorbs from a bump at an uncontrolled rate. A suspension built on springs alone would make for an extremely bouncy ride and, depending on the terrain, an uncontrollable car.

Enter the shock absorber , or snubber, a device that controls unwanted spring motion through a process known as dampening. Shock absorbers slow down and reduce the magnitude of vibratory motions by turning the kinetic energy of suspension movement into heat energy that can be dissipated through hydraulic fluid. To understand how this works, it's best to look inside a shock absorber to see its structure and function.

A shock absorber is basically an oil pump placed between the frame of the car and the wheels. The upper mount of the shock connects to the frame i. In a twin-tube design , one of the most common types of shock absorbers, the upper mount is connected to a piston rod, which in turn is connected to a piston, which in turn sits in a tube filled with hydraulic fluid. The inner tube is known as the pressure tube, and the outer tube is known as the reserve tube. The reserve tube stores excess hydraulic fluid.

When the car wheel encounters a bump in the road and causes the spring to coil and uncoil, the energy of the spring is transferred to the shock absorber through the upper mount, down through the piston rod and into the piston. Holes perforate the piston and allow fluid to leak through as the piston moves up and down in the pressure tube.

Because the holes are relatively tiny, only a small amount of fluid, under great pressure, passes through. This slows down the piston, which in turn slows down the spring. Shock absorbers work in two cycles — the compression cycle and the extension cycle. The compression cycle occurs as the piston moves downward, compressing the hydraulic fluid in the chamber below the piston.

The extension cycle occurs as the piston moves toward the top of the pressure tube, compressing the fluid in the chamber above the piston. A typical car or light truck will have more resistance during its extension cycle than its compression cycle. With that in mind, the compression cycle controls the motion of the vehicle's unsprung weight, while extension controls the heavier, sprung weight. All modern shock absorbers are velocity-sensitive — the faster the suspension moves, the more resistance the shock absorber provides.

This enables shocks to adjust to road conditions and to control all of the unwanted motions that can occur in a moving vehicle, including bounce, sway, brake dive and acceleration squat.

Struts perform two jobs: They provide a dampening function like shock absorbers, and they provide structural support for the vehicle suspension. That means struts deliver a bit more than shock absorbers, which don't support vehicle weight — they only control the speed at which weight is transferred in a car, not the weight itself.

Because shocks and struts have so much to do with the handling of a car, they can be considered critical safety features. Worn shocks and struts can allow excessive vehicle-weight transfer from side to side and front to back. This reduces the tire's ability to grip the road, as well as handling and braking performance.

Sway bars also known as anti-roll bars are used along with shock absorbers or struts to give a moving automobile additional stability. A sway bar is a metal rod that spans the entire axle and effectively joins each side of the suspension together. When the suspension at one wheel moves up and down, the sway bar transfers movement to the other wheel.

This creates a more level ride and reduces vehicle sway. In particular, it combats the roll of a car on its suspension as it corners. For this reason, almost all cars today are fitted with sway bars as standard equipment, although if they're not, kits make it easy to install the bars at any time.

But the four wheels of a car work together in two independent systems — the two wheels connected by the front axle and the two wheels connected by the rear axle. That means that a car can and usually does have a different type 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 known as a dependent system , while the latter arrangement is known as an independent system. In the following sections, we'll look at some of the common types of front and back suspensions typically used on mainstream cars. Dependent front suspensions have a rigid front axle that connects the front wheels.