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What is a Shock Absorber?

M. Rosario
M. Rosario

A shock absorber — often just called a "shock" — is a mechanical apparatus whose primary purpose is to cushion movements and impacts. It is often found in automobiles, where it is used to provide a smoother ride. In construction, a shock absorber is commonly called a damper. It serves as a safety measure to help minimize a structure's movement caused by natural forces such as strong winds and earthquakes.

Shock absorbers work by absorbing excess kinetic energy usually resulting from sudden or strong movement. The kinetic energy is then discharged by storing or transforming it into another form of energy. Absorption and dissipation of energy varies depending on the type of shock absorber used.

Worker
Worker

Objects like spring coils tend to bend or compress whenever excessive stress is put on them. During compression, energy is transferred to the material. A hysteresis shock absorber utilizes this effect by using materials that can retain their shape after absorbing tremendous energy. The disks found in the spinal column work in the same principle as a hysteresis shock absorber.

Friction type shock absorbers use a material's natural resistance to reduce energy. Shock absorbers of this type are usually called dashpots. The manufacturing industry frequently uses dashpots to lessen equipment vibration. This is commonly done to reduce the wear and tear on the machine. Shock proof gadgets also usually have some form of friction shock absorbers to prevent damage when they are dropped.

Hydraulic and gas shock absorbers use fluids, like hydraulic oil and air, contained in a cylinder to absorb energy. Outside force causes a piston on top of the cylinder to push on the fluid. Tiny perforations on the cylinder bottom then allow a small amount of fluid to pass through. Letting fluid flow out of the cylinder prevents too much pressure from accumulating and ensures smoother recoil.

Car shock absorbers normally integrate both spring and hydraulic shocks. They form the suspension that connects the chassis to the body of the car. By using two types of shocks, the suspension more effectively lessens the shakes experienced by the passenger.

The stiffness of the suspension is typically adjusted depending on the desired level of control. A soft suspension emphasizes on a comfortable ride, while a hard suspension usually gives a more responsive handling. Race cars often have different stiffness settings between the front and rear shock absorbers. The front suspension is normally tuned for faster turning. The rear suspension, on the other hand, is calibrated for increased traction.

Discussion Comments

ValleyFiah

@Framemaer- If you are just using your car for your daily commute, you can get by with the OEM replacement parts that you can find at any mechanic. Purchasing the best shock absorbers on the market would simply be overkill. All parts installed on your vehicle by a reputable mechanic should at least meet factory original specifications. You only need to install better parts if you are looking to improve the performance of your vehicle.

As for buying the parts yourself, it is often cheaper than ordering the parts through a dealer. Dealerships will charge as much as they can for factory original parts, even though those parts are sometimes less reliable than a quality aftermarket part. Independent mechanics will often use similar parts to the ones you would find at an Autozone or Napa, and they get B2B discounts that you would not receive. This translates to a mechanic mark-up price that is nearly equivalent to those you could find shopping around.

FrameMaker

What is the difference between shock absorbers and struts? I know very little about cars, and like PelesTears, I would like to know about when they need replacement. How do I know if my car needs shocks or struts?

I saw a deal advertised in the Sunday paper for buy 3 get one free shocks. My friend told me I would save money if I buy the parts for my car and have the dealer put them on. He said that the mechanic may not always order the best parts, and they add a surcharge to the price of the part.

This is my first car that I have been responsible for repairs on, and I would greatly appreciate any advice.

PelesTears

When do I know when shock absorber replacement is necessary? My truck has about 75,000 miles on it, and it seems like the suspension is soft. The truck leans significantly when taking corners and and sways when other vehicles pass by (ex. when I am trying to turn left).

I took it to the dealership to see if the shocks should be replaced. They told me that shock absorbers only need to be replaced when they are leaking or broken. I would think that shocks and struts would have an operational lifetime similar to any other mechanical component. I would hate to have to ride my vehicle to the ground before replacing components.

I wonder if the dealership says I do not need new shocks because my truck is still under an extended warranty. Would a car manufacturer be so shady as to not perform repairs because it could save them money? Are there any ways that I can prove that my shocks are unsafe and need to be replaced? What are the risks if I do not get the shock absorbers replaced?

StarJo

In my college three-dimensional art class, we had to make our own shock absorbers. We had to design a structure that would keep eggs from breaking after being dropped from a two-story building.

Most people used thick styrofoam to absorb the shock. Homemade parachutes reduced the impact, and the foam was able to absorb the remaining force, keeping the eggs intact.

I made a nest of Easter egg grass to put inside of a styrofoam bowl. The grass provided extra shock absorption, though I’m sure the foam bore the brunt of the force.

wavy58

I prefer the shock absorbers in my car to those in my husband’s pickup. I have a much smoother ride than he does, so if we are carrying delicate objects, we take my car.

His truck bounces all over our road, which is full of potholes. I feel so jostled when riding in it. He says he needs to have the shock absorbers replaced, so it’s even worse now than it used to be.

I know that pickup trucks generally ride rougher than cars, but his is ridiculous. I’m sure once he replaces the shocks, it will be at least bearable.

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