Complete Guide of Car Suspension System

A car suspension system consists of various parts. It includes tires, springs, shafts, linkages, struts, joints, bushings, arms, and shock absorbers that connect your vehicle to the wheels creating a relative motion between them. The system neutralizes the forces received by the vehicle while driving on the road making sure it does not lift off from the road.

In most cases when you think of your vehicle’s performance, you normally think of the speed, the engine’s power or sound, and the rate of acceleration. All these will be of no use if you cannot drive your vehicle comfortably. The car suspension system offers you a great driving experience. This article explains everything you need to know about your vehicle’s suspension system.

What Is The Function Of The Suspension System In Your Car?

What is a suspension system? What is the purpose of this system? If you have asked this question before then I shall make it simple for you. As a car owner, it is crucial to understand the suspension system’s parts and functions. The main functions of this system are to ensuring contact between tires and the surface of the road, providing good handling and steering ability, and keeping proper alignment of the wheel.

It also helps in supporting the weight of your vehicle (the engine, body, and frame included) and ensuring passenger comfort by dampening and absorbing the shock formed when you drive over rocky or uneven ground. There are various types of suspension systems in automobiles but they all perform similar functions regardless of their design.

The efficiency of a suspension system determines the amount of stress your vehicle will be able to withstand. Your vehicle’s tires and the amount of tire air are an essential part of your suspension system. Tires are the only component of the suspension system that comes in contact with the surface of the road. This implies that they are needed to steer and apply pressure to the road simultaneously and play a big role when it comes to stopping the vehicle.

Besides the seats and tires, your suspension system is a key mechanism that disconnects your seated backside from the surface of the road. It also stops your vehicle from experiencing a high vibration. Individuals who travel by railway are exposed to a high vibration due to the absence of a suspension system in the mechanism of the train.

A lot of modern cars have dependent suspension systems on the back and front of the vehicle allowing the various wheels to move independently. Some cars still use a basic beam axle, but most modern vehicles use live axles. The live axles support the weight of your vehicle and move the wheels connected to it. The issue with rear tires is that they do not move on their own. They maintain the same angle to one another rather than with the surface of the road.

This, therefore, implies less predictability and resistance in handling. It is why this type of suspension system is been used by automobile companies to design new vehicles. Independent front suspension permits the front wheel to move up and down along with the strut. The spring assembly is fixed to one side and a control arm on the other side. The movements at the various connection points are absorbed and moderated by the bushings.

The placement of each of the components in the front suspension system is vital since your front wheels need to steer and keep a uniform alignment to ensure the safe operation of your vehicle.

The rear suspension also uses similar technology as the front suspension system without deliberation in the steering dynamics because the rear wheels normally do not steer. All-wheel and rear-wheel drive automobiles have an inequality mounted to the middle frame of the control arms. While the front-wheel-drive automobiles have a simple independent rear suspension, which only needs the shock absorbers and the springs.

The springs and shock absorbers are all components of your suspension system that allows all the compressions and cushioning when there is movement in the suspension system. Springs gives the force needed to hold the sprung weight off the wheels and resist compression.

When you can drive comfortably in your vehicle, it means that the car suspension system has efficient road isolation. It also shows your vehicle’s suspension system can move freely when needed without jarring your car.

The road-holding ability of your vehicle is determined by how well your vehicle can keep good traction and a uniform weight spread when several forces are involved. To be stable when stopping your vehicle, you need a good suspension system that won’t let your front go down as you apply pressure to your brake pedal. You enjoy your ride; you need a suspension that stops your car from scorching while trying to accelerate.

An effective suspension system allows you to drive your vehicle with ease and comfort. Therefore, if you experience any squeaks, excessive bouncing, over-steer or under-steer traction problems, or unusual brake noises while driving over dips or bumps is not normal. This answers the question on what is the purpose of the suspension system.

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Working Principle of the Suspension System

The suspension system in your vehicles operates on the principle of ‘force dissipation”. The systems convert the force it receives to heat, thus eliminating the impact that could have been made on your vehicle. The suspension system includes struts, springs, shock absorbers, or dampers to make this possible. The spring holds the force while the damper converts the force into heat.

One crucial part of the suspension system is the spring. Its function is to store energy got from an impact when your vehicle passes through bumps. It stores this energy by compressing its normal size and converts any form of force to energy.

The amount of energy a spring can hold is dependent on factors such a material, coefficient, and length of the spring. The quality of material used in manufacturing the spring determines if it will falter.

There are two types of springs used in the making of a suspension system. They include a leaf and coil spring. A coil spring is what is used in most vehicles, while a leaf spring is used for trucks. A leaf spring has a higher storage capacity than a coil spring. Springs helps in providing cushion. At times the vehicle might bounce while driving, making it difficult for you to drive your car. For this reason, always make sure your dampers are working effectively.

The amount of energy stored in springs needs to be channeled somewhere else less it will be released making the vehicle bounce when driving. Once the energy has been stored by the spring, absorbers or dampers begin to function. There is a piston inside the damper, which has holes and some amount of pressurized oil.

Immediately the spring passes on the energy to the damper, the piston using the spring’s energy pass through the pressurized oil. This leads to the generation of heat and the force caused by the impact is converted to heat energy. This negates any other remaining energy that could have caused your vehicle to bounce.

Different components of the suspension system play individual roles but they all function as one for the success of the system. Like described earlier, the suspension system takes care of your vehicle’s weight, road shocks, and handling so you can have an enjoyable drive. It is important to understand how the suspension system operates so that you get to know immediately it gets faulty. The suspension system PPT explains some basics you need to understand about the system:

Oversteer:

The term ‘oversteer’ is used in describing a driving condition where your back tires get to their cornering limit before the front tires. This can cause the back tires to lose thus causing the vehicle to spin. However, oversteer can be an advantage in certain driving conditions. If the back of your car slides each time you drive on wet roads, know that it is a result of oversteer.

To avoid this situation, steer in the direction of the turn. Then, lower the speed by slowly releasing pressure from your brake pedals until you recover full control of your vehicle. Do not apply brakes, as this can worsen oversteer due to a reduced back tire friction.

Understeer:

Understeer is the opposite of oversteer. This happens when front wheels cannot make a turn through a turning radius due to loss of traction by your front tires. This condition makes your vehicle unable to turn. When turning on a wet road, your vehicle might continue moving in a straight direction instead of turning.

The understeer can be determined by the difference between the angles of the tires and the desired angle to make the turn. However, some vehicles have been designed to have understeer. This is because the understeer can be lowered by reducing the vehicle’s speed, which is considered a safety measure.

Neutral Steering:

When the vehicle turns at an equal rate as your steering wheel, your vehicle is diagnosed to have a neutral steering condition. It implies that your vehicle will cause neither oversteer nor understeer.

Lateral Acceleration:

This is the measurement of the vehicle’s ability to corner. The feeling you get during cornering results from a force pushing your vehicle to the outside of the turn. That’s why a lateral acceleration test is carried out on vehicles by driving on a large track circle at increasing speeds.

The faster you drive around the circle, the higher the lateral acceleration. Vehicles with higher lateral acceleration handle cornering effectively. Sports vehicles are designed to have a higher lateral acceleration than regular vehicles.

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How Does the Suspension System Affect Handling?

Proper functioning of the suspension system enables you to have full control of your vehicle while driving. Every car owner must take proper care of their vehicle’s suspension system. The suspension system is not just an ordinary part of the vehicle since it enables you to handle and drive your vehicle comfortably.

The wear and tear of the suspension system components reduce its functionality in terms of handling and car stability. This can still happen even when driving on a smooth surface. It is advisable to inspect struts, absorbers, and springs regularly.

Regular checkups help you know when to replace worn-out or damaged suspension parts. This prevents any chance of having a stiff suspension and premature wear and tear of your vehicle’s tires and other major suspension components.

The struts and shock absorbers are also essential parts of the vehicle’s suspension system. They ensure that you do not feel the impact as you drive over bumps. Having damaged absorbers and struts affects the ride and handling characteristics making it very difficult to drive the vehicle.

This fault also affects the contact of your wheels to the surface of the road. Driving with worn-out struts and shocks can make your vehicle sway abruptly, making you lose control of your vehicle while driving. If your vehicle has worn-out suspension parts, it increases the rate at which other suspension parts get worn out. This eventually causes more damage to the system preventing it from functioning properly.

Damages or worn-out parts of the suspension system need to be changed as soon as possible. This helps you maintain proper handling of your vehicle by providing a stable braking condition, keeping the tires on the road surface, controlling the sway, and maintaining a proper wheel alignment.

The steering wheel is considered a non-direct component of the suspension system. You, therefore, need to make sure there is a high level of power steering fluid in the system to lubricate and increase the effectiveness of the power steering system. If you fail to check the amount of steering fluid in your system, the steering will become hard to turn to make it challenging to control your vehicle’s direction.

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Suspension Parts Names and Short Descriptions

There are two major suspension system parts in most modern designs. They include dampening and spring mechanisms. Other components that make up the suspension system are strut, bushings, joints, and linkages just to mention a few. Here is a list of various suspension system parts and function:

Springs

Springs enable the vehicle to withstand any bumps you come across while driving. The spring also provides support to your vehicle enabling it to hold extra weight without bending or sagging. You need to also know that the spring is a vital part of the suspension system that helps the vehicle to remain at a predetermined height. Here are the three major types of coil uses in designing the suspension system of modern vehicles:

Coil Springs: Coil springs are similar to the regular springs but are large and features heavy torsion bars. The torsion bars are coiled around its axis. This spring compresses and expands to absorb the vibrations from the vehicle’s wheel while in motion. Coil springs are used in manufacturing the suspension system of most modern vehicles.

Leaf Springs: The leaf springs were used in manufacturing suspension systems for early generation automobiles. The best thing about this spring is it makes the system very easy to assemble. It is also used in manufacturing trucks and heavy-duty vehicles.

Torsion Bars: Torsion bars give an object a twisting ability to make it behave like a spring. It is similar to that of a coil spring. In this case, the object is a steering bar, one end of the bar is linked to the vehicle’s frame, and the other end is linked to the wishbone. The wishbone is used as a lever.

When you drive over bumps, the movement of the wheel is transferred to the wishbone. It then moves the torsion bar and causes the torsion’s twisting, making it behave like a spring. This system is used by automobile companies in most European countries.

Air Springs: This type of spring depends on the power delivered by the air compression. The type of mechanism is known as an Air spring suspension. It is mostly used in manufacturing the suspension systems in buses and trucks, including most passengers’ vehicles. It is very smooth and efficient in suspension systems. Air springs largely absorb shocks and vibrations using a comprehensive ability. In modern vehicles, electrical air suspension systems are designed to have independent functions, including lifting and lowering modes.

Shock Absorber

Another component explained in car suspension parts names pdf is the shock absorber. It reduces the actions of the suspension springs and reduces vibrations simultaneously. The shock absorber transforms kinetic energy into heat energy which is released using hydraulic fluid. You can picture the shock absorber to be like an oil pump found between your vehicle’s wheels and frame. The top end of the absorber is linked to a piston rod.

Car Suspension Shocks

The piston rod is connected to a piston that rests in a tube filled with hydraulic fluid. An inner tube is used as the pressure chamber, while its outer tube is used as a reservoir for storing extra hydraulic fluid. A suspension components diagram will help you understand these parts better.

When you go over a bumpy road, your wheels transmit the energy to the springs in the suspension system. This energy is then transmitted to the upper end of the shock absorber and to the piston rod, which goes through the piston. The movement of the piston in the tube allows the hydraulic fluid to escape. However, the small holes do not allow much quantity of fluid to escape thus reducing the piston’s rate.

You also need to know that there are two cycles in the functioning of the shock absorber. The first is your piston’s downward movement, which compresses the hydraulic fluid underneath the piston. The second is the piston’s upward movement. This compresses the hydraulic fluid above your suspension piston. This compression cycle helps manage sprung weight in the vehicle while the other cycle manages sprung weight.

All shock absorbers are velocity-sensitive. Increasing motion in the suspension system increases the resistance provided by the shock absorber. It enables shock absorbers to blend easily with various road conditions such as bouncing, acceleration squatting, say, and brake diving.

Suspension Struts

Suspension struts are a dampening component of the suspension system that operates like a shock absorber. They are seen as shock absorbers that have already been fixed inside the coil spring, making it a two-in-one suspension component.

You need to know that your vehicle’s shock absorber does not support and manage the entire mass of your car. This is done by the suspension struts. Therefore, without the suspension struts, your vehicle will likely sag or bend.

Tires and wheels are amongst the suspension car parts list located outside the system. Tires are vital since they come in contact with the surface of the road while driving. Each time you drive over bumps, most of the impact is taken by the tires. Your cornering, braking, and acceleration also have huge impacts on the tires. Punctured or worn-out tires, affect your driving negatively.

Bushings/Bearings/Joints

Bushings, bearings, and joints are responsible for keeping the linkages linked to the larger components. The parts allow some twisting and sliding movement of specific suspension parts. These parts need lubrication regularly to prevent them from wearing out fast.

Tie Rod Ends

The steering wheel is linked to the steering gear. This is what enables the wheels to be turned by the steering wheel. The steering gear is linked to your wheels through the tie rod ends.

The tie rod end’s design is to make sure that there is the proper alignment of your vehicle’s wheels to prevent the outer and inner edges of the wheel from wearing out. A worn tie rod can cause wheels to start shaking.

Linkages

Several rods connect various components of the suspension system. These rods are made up of metal and are durable throughout the lifespan of your vehicle. The only situation that can severely affect the functionality of the linkages is when they are severely damaged due to an accident.

Frame

The frame is one of the major parts of the suspension system in the vehicle. It is the outside structure that lifts the entire vehicle’s weight and load. The frame also supports the engine and body of your vehicle. A lot of other parts of your suspension system also assist in this function.

Steering Wheel

The steering system is not a direct component of a suspension system. Nevertheless, it works with the suspension system to ensure the turning of the wheels. The joints, wheels, linkages, and some other various components are controlled to an extent through the steering system. Each time you turn your steering, the wheels turn simultaneously.

Anti-Sway Bars

Anti-sway bars are also part of your vehicle’s suspension parts list. They are sometimes referred to as anti-roll bars. This part gives the vehicle extra stability while driving. They are used in tandem with your suspension shock absorbers or struts.

When motion occurs in the suspension of one wheel, the movement is transmitted by the anti-sway bars to the other wheel so that you can have an even ride. This function reduces the swaying tendency of your vehicle, mostly when you are about to make a turn.

Ball Joints

Ball joints connect your steering knuckles to the control arms. The ball joint is a flexible joint that allows easy movement of the movable suspension components, including the steering wheels.

Most vehicles have many ball joints assemblies in their suspension system. This however depends on the type of suspension system the vehicle is using. If you have faulty ball joints, the suspension system can fail to make the vehicle lose control while driving.

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Types of the Suspension System

There are various suspension systems for vehicles, trucks, and other heavy-duty automobiles. The type of system used in a vehicle depends on its design and its purpose. This is the list of the types of suspension system you need to know:

Dependent Suspension System

The dependent suspension system consists of springs, mostly leaf or coil springs. Linkages and absorbers are also a part of the system. It has a lot of setups, and it is a little difficult to assemble. Two popular classifications of suspension systems include dependent and independent suspension systems.

A dependent suspension system means that a beam or axle is linking the left wheel to the right wheel thus operates in tandem with each other. It is made by combining either coil spring and shock absorbers or leaf spring and shock absorbers. The system is known to be durable and affordable.

Torsion Beam

The torsion beam is commonly known as the twist-beam suspension. This type of dependent suspension system is easy to manufacture and affordable. This system uses trailing arms integrated with the cross member that turns as the wheel is in motion. The torsion beam is usually found in the middle of the solid axle and the independent suspension.

This design provides a spacious cabin as the suspension system is more simple and together. It is cheap to manufacture and mostly used in smaller hatchbacks and sedans.

Live Axle

The live axle is a driven solid axle. It transfers power to the wheel of the vehicle, which is contrary to the torsion beam. Live rear axle suspensions are mostly used in buses, SUVs, and some light trucks. This type of system can be sprung by either using leaf or coil springs. It is a more reliable and ideal system when dealing with heavy load duties.

Independent Suspension

Independent suspension requires a bar to connect the wheels of the vehicle. Each of the vehicle’s wheels has its shock absorbers and springs. This enhances the effectiveness of the automotive suspension and steering system. It gives the driver a more comfortable experience while driving. When part of the wheel is stepped over a bump on the road, it will not affect the other wheels of the vehicle. Independent suspension systems can be used on the back or front wheel of a car. Below is an example of an independent suspension system diagram:

It is common to see this type of suspension system on most cars’ front. This is because it keeps the front wheels on the ground making sure that your car is aiming in the right direction while driving. Over the years, various automobile industries have used different types of independent suspension systems when manufacturing automobiles. The various types include:

MacPherson Strut

Macpherson strut is a type of independent suspension system that uses a compression linkage or wishbone that is stabilized by another linkage. Most people see it as a shock absorber that is embedded inside the coil spring. This type of suspension system is mostly seen under front-wheel drive vehicles.

The MacPherson strut is one of the most efficient and less expensive independent suspension systems due to its fewer parts. This suspension system does not consume large space. It is therefore a perfect fit for small vehicles. It is also easier to fix than other kinds of suspension systems.

Double Wishbone

The double-wishbone suspension system consists of two arms that are wishbone-like. These arms are connected to the wheel. Each of the arms has different mounting positions. One is located at the vehicle’s frame while the other is located at the wheel. The MacPherson strut has similar features to the wishbone suspension system as they both have coil springs and shock absorbers.

One of the major benefits of the wishbone suspension system is a rise in the negative camber due to the movement of the two arms. The wheel of your vehicle keeps full contact with the road while cornering. This results in better vehicle performance and handling. If your vehicle happens to lean on one side when trying to corner, the vehicle’s wheel will remain perpendicular to the road. This ensures that the tires have full contact with the surface of the road.

Multi-Link

The multi-link suspension system uses three or more arms connected to the wheel, unlike the double-wishbone that utilizes just two arms. The multi-link system is much more expensive than the MacPherson strut and the double-wishbone suspension system. It is also more complicated and difficult to manufacture. It is used in a few modern cars that use the set-up of the MacPherson strut and the multi-link suspension at the back of the vehicle. Since it is more expensive to produce, this type of system is mostly found in more expensive vehicles.

This suspension system can have a freer movement than the earlier mentioned independent suspension systems because of its high number of linkages connected to the wheel. Another benefit of the Multi-link suspension system is that it provides more options for the proper alignment of the wheel.

Frequently Asked Questions (FAQs)

Q. Which Type of Suspension Is Best for the Car?

MacPherson suspension strut is the most widely used front suspension system in an automobile today. European brands mostly use this. It is widely known as a shock absorber built in a coil spring to perform as a single cohesive unit. It is more definite in the front wheel of drive vehicles.

After various researches done by several automobile industries, the MacPherson Strut has been proven to be the simplest and cheapest choice for independent suspension. It has been in use since it was invented far back in the 1940s.

Q. How Long Does a Car Suspension Last?

Like most automobile parts, the car’s shock should follow a specific maintenance pattern. The durability of your vehicle’s suspension depends on several factors, including the type and materials it is made from. Expert mechanics say that the shock absorber should be replaced every 45,000 to 90,000 miles.

However, it is difficult to place a specific duration to this as they are a lot of variables that need to be considered. Though on an average scale, if you have a good quality suspension system, it should last for roughly four to five years.

Q. Is Suspension Repair Expensive?

After long usage of your vehicle, the suspension system may need to be replaced or repaired as a result of damages, aging, or other environmental reasons. The cost of a suspension repair is usually within a range of $700-$4000. The actual car suspension parts price is determined by the type of your vehicle’s suspension system, the model, and the manufacturing date of your car.

Your suspension repair cost also depends on the extent of wear, tear, and rust which makes the process more difficult. For an average vehicle, the cost of repair is $150-$1000. For expensive cars, the cost of repair is $1500-$4900. If you decide to do it yourself, repair costs should be reduced to about $110 – $200.

Q. Can You Drive With a Bad Suspension?

If you know how does the suspension system work, then you know the answer is NO! It is dangerous to drive a vehicle with a damaged or collapsed suspension system. It causes a clunking or rattling noise from steering, sagging noise from the suspension, and affects the aligning parts. The ride will become rough and unpleasant since the vehicle becomes difficult to control when there’s an emergency.

This causes struts to wear out, leading to longer stopping. The car’s weight may shift unnecessarily and unexpectedly during braking affecting one’s ability to stay in control when driving. It eventually causes a break in the wheel or a flat tire which can lead to an accident.

Q. How Long Will It Take to Change a Suspension System?

Replacement of suspension varies from one mechanic to the other. It depends mainly on the knowledge, level of expertise, and also understanding of that part of the vehicle. Getting an experienced mechanic is crucial due to the system’s complexity. However, replacing a single set of suspension systems takes about 3-4hours. But have in mind that repair varies depending on where you are the mechanic and the type of suspension system.

Q. How Much Does a Suspension Inspection Cost?

If you decide to carry out this process yourself, an inspection of a suspension system will cost about $100-$300. Suspension inspection is carried out by checking the bushes, shock absorbers, and other components.

A road test is also done to check for noises or excessive body roll. When this is done, inspection charges raise to $300-$500. The price also depends on what part of the suspension system needs to be inspected, e.g., shock absorber inspection causes $100-$700. Suspension bush inspection costs between $100 and $300.

Q. How Do I Upgrade My Suspension?

If you have a mechanic tools box it will be easy to do an upgrade by yourself. A suspension upgrade is simply done by adjusting suspension settings, which are shocks, leaf springs, switching to bigger wheels, torsion bar, lift kit, and strut braces. This can be done by adjusting the anti-roll bar in your vehicle, also known as blade adjusters. The lever can also be manipulated to adjust the setting of anti-roll bars.

Upgrading of the suspension system can be of different forms. The main aim is to reduce or stop ride height, improve center of gravity, transitional weight transfer under acceleration, downward movement, and cornering loads. Upgrade suspension is done by upgrading the full suspension system or making sure that the full package is faultless.

Final Words

All the above information has all you need to know about car suspension systems. We hope that this has been able to give you a broad insight regarding this topic. However, you can still drop a comment to us if you need more clarification on any aspect. Make sure you check your vehicle’s repair manual before conducting any form of repair and if you do not understand the technical aspects contact your mechanic.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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