The shock absorber is an indispensable part of the suspension of a modern car. Without it, the operation of the machine in conditions of constant vertical swing will be impossible.

Shock absorbers reduce the vibration frequency of the springs that support the car body and make it move more smoothly over uneven roads.

Today, the shock absorber market is represented by the widest range of products, so the question of which shock absorbers are the most reliable and safe - hydraulic or gas - does not lose its relevance. Each type of shock absorber has its own characteristics, advantages and disadvantages.

Hydraulic shock absorbers perform the function of significantly reducing the amplitude of suspension oscillations during compression or relaxation. The hydraulic shock absorber consists of a working cylinder, a compensation chamber, a rod with a piston, a guide sleeve and a damping fluid - oil. The effect of vibration damping is achieved due to the oil, which, moving from one part of the shock absorber to another, takes on the resistance of the springs, thereby extinguishing their destructive force.

Disadvantages of hydraulic shock absorbers:

• Low heat dissipation: during prolonged driving, the oily fluid in the shock absorber can overheat and lose its cohesive properties, resulting in loss of efficiency.
• Low efficiency when operating a car on rough roads with frequent sudden movement of the piston, the oil mixes with air bubbles, its viscosity decreases, which negatively affects the operation of the shock absorber and can damage it

The main advantages of hydraulic shock absorbers are their affordable price and small size.

Gas-filled shock absorbers differ from hydraulic ones in that the compensation chamber in them is filled with gas, which is pumped there under high pressure. This is the reason for the significant advantage of gas shock absorbers over oil shock absorbers - high pressure forces the piston to always be in a preloaded state, due to which, when overcoming road irregularities, the shock absorber stiffness changes non-linearly, thereby providing better vehicle controllability.

When choosing a shock absorber, you can be guided by different criteria, the operating conditions of the car, driving style, views on the level of rigidity and comfort.

The serviceability of any shock absorber must be monitored, because in the event of its failure, the quality of adhesion of the car's tires to the roadway deteriorates significantly, which reduces its stability and controllability when driving on uneven roads, in corners, and also increases the braking distance. In addition, the wear of all suspension parts and brake mechanisms is accelerated.

In order to avoid negative consequences, faulty shock absorbers must be replaced or repaired.

To extend the life of the rubber shock absorber seals, it is recommended to treat with a silicone oil-based compound. This lubricant prevents rubber from drying out and cracking and is resistant to water and most chemicals.

EFELE materials are effectively used for mounting / dismounting shock absorbers.

For example, universal grease is ideal for dismantling shock absorbers.
. This agent forms a stable moisture-repellent film on the surfaces, perfectly displaces water. EFELE UNI-M SPRAY universal grease is a dispersion of solid lubricants in mineral oil. It has high penetrating properties and softens rust well, which greatly facilitates dismantling. At the same time, EFELE UNI-M SPRAY has good lubricating properties, which protects shock absorbers from wear.

EFELE UNI-M Spray universal grease combines properties that other universal greases cannot combine. On the one hand, it easily penetrates to the most inaccessible nodes, on the other hand, it does not flow out of the friction zone.

The bearing capacity and anti-wear properties of EFELE UNI-M Spray universal grease are enhanced by the introduction of solid anti-friction fillers into its composition. The presence of corrosion inhibitors provides dispersions with excellent anti-corrosion properties.

It is hard to imagine how the car would drive and what sensations the driver and passengers in the cabin would experience if the vehicle were not equipped with special devices that could extinguish, or at least minimize the oscillatory movements transmitted by springs, springs, torsion bars. For this purpose, shock absorbers are used, quite rightly they are considered one of the most important elements of an automobile suspension, they are designed to eliminate vertical swaying of the body.

To choose the best shock absorbers for your car, it is advisable to first familiarize yourself with manufacturers that are recognized all over the world.

Koni

Shock absorbers are the only product manufactured by the Dutch company. The main difference is the adjustability of the characteristics of the models, and there is a difference of 100% between the zero and maximum adjustment positions, i.e. there is a real possibility of adapting the device to any type of road, any car model and driving style.

The range of the company is 2500 different models, differing in design schemes. Their cost on the market is the highest, as well as reliability, there is a chance that they will fail along with the car.

Most popular models:

• KONI Load-a-Juster - for a solidly loaded body
• KONI Special - for a smooth ride
• KONI Sport - for lovers of reckless at high speeds

Bilstein

They are installed by manufacturers on cars Lamborghini, Jaguars, Ferrari, which is already evidence of the highest quality.

The most popular models Bilstein Sport, Bilstein Sprint, Bilstein Rally are designed for high-speed, sports cars, they are chosen by fans to show a driving master class. There were no complaints about the quality of Bilstein products.

Kayaba

The products of the Japanese company Kayaba are preferred by world-famous car manufacturers: Renault, Ford, Seat, Peugeot. Kayaba shock absorbers won the sympathy of drivers with affordable cost and quality that meets international standards.

Among the most popular are gas-hydraulic Ultra SR models with high damping characteristics, stabilizing grip on the track surface, with good handling characteristics when using low-profile tires, in the absence of attenuation. This is preferred by lovers of a hard driving style.

BOGE

The main consumers of the products of the German company are the leading European concerns that produce cars BMW, Volkswagen, Volvo, Alfa Romeo, Audi.

The price policy of the manufacturer of shock absorbers is quite affordable for owners who really care about the technical condition of their cars. Installed on a foreign car, BOGE shock absorbers do not adversely affect suspension performance.

Most in demand:

• Boge Pro-gas, gas-filled, for a comfortable ride
• Boge Turbo24, single-pipe, allowing you to ride in off-road conditions on an all-wheel drive car
• Boge Turbo-gas, for sports cars
• Boge Nivomat, maintaining optimal ground clearance even with a significant load on the body

Monroe

The Belgian company is a manufacturer of shock absorbers known throughout the world.

Accurate and instantaneous response is provided by the original design of gas models, it also allows:

• easy to adapt to riding in different, even difficult conditions,
• control comfort,
• adequate vehicle behavior during complex maneuvers at speed

The American company enjoys the best recommendations not only at home, but throughout the world.

A particularly popular product series is Reflex, whose models guarantee maximum contact with the road surface.

TOKICO (HITACHI)

The Japanese company manufactures damper devices for the automotive industry in the United States and Japan. The products are of high quality, with a long service life, the cost is low - the prerequisites are sufficient for popularity.

But when buying, you should be wary of Chinese fakes, there are a lot of them on the domestic market, it is quite difficult to distinguish visually from the original.

It manufactures brake systems, hydraulics and pneumatic equipment for cars, shock absorbers. It has been successfully operating on the market for about 80 years, occupying a leading position. A special merit of the company is the development of a two-tube gas model of a low pressure shock absorber, which has advanced the entire industry as a whole.

Since 2005, TOKICO began to work as part of the HITACHI concern, its products are used in the assembly of sports motorcycles, as one of the most reliable in the world.

SACHS

The German manufacturer specializes in the manufacture of clutches and shock absorbers, the products are universal, high-quality and reliable. Today the company pays more attention to the production of pendants.

The most popular modifications:

• Super Touring - for a comfortable ride on a car of various types
• SACHS Advantage - for a sporty driving style, for a comfortable ride on the roadway of any complexity

KYB

In a relatively short period of existence (about 20 years), the Japanese company managed to gain trust and popularity; Mazda, Toyota, Honda cars are equipped with its products.

Al-KO

The company's products continue to delight motorists with inexpensive but high-quality products for four decades.

Dampers from Al-KO are installed on expensive motorcycles and cars, for the most part they are oil, they are preferred by owners of used vehicles.

DELCO

Manufactured in the USA, mostly used by American vehicle manufacturers. It is almost impossible to meet them on open sale, the main consumers of DELCO products are auto assembly shops.

However, DELCO shock absorbers are well known and highly recommended for their reliability. In off-road conditions, it is irrational to use.

Shock absorber, principle of operation, where installed

And now let's continue talking about shock absorbers, clarify on what principle they work and continue the topic of how to make the right choice of device for your car.

The shock absorber is a damping device that dampens vibrations, absorbs shocks and shocks of moving structural elements (suspension, wheels), body. The action is based on the process of absorbing the mechanical energy of oscillatory movements and converting it into thermal energy.

The interaction of the part with springs, pillows, torsion bars, springs allows you to dampen the free movements of large masses and prevent relatively high speeds of smaller masses associated with elastic elements.

The wheels of the car must be able to move freely up and down relative to the body. The mass of the body must be distributed to the suspension springs, to keep them compressed to a certain extent.

Fulfillment of these conditions will allow maintaining contact between the tire and the road surface, regardless of what will be under the wheel - a bulge or a depression. If shock absorbers are removed from the structure, constant contact will not be possible due to the oscillation of the springs.

For example, a driver can feel a malfunction of a damper device even when driving at a speed of 30 km per hour:
wheels bounce from the slightest bumps
vehicle control is deteriorating

One of the important points is the location of the part. The most efficient operation will ensure the minimum distance of their installation site from the wheel.

Experts emphasize that shock absorbers must be installed strictly vertically, i.e. perpendicular to the suspension plane. Even with minimal deflection, the damping efficiency will decrease.

It is extremely harmful to hold the opinion that this device is simple in principle of operation and primitive in design. In fact, the correct installation of the node and ensuring its excellent operation is a rather complicated science, requiring multifaceted knowledge in the field of physics and mechanics.

What do the main indicators of shock absorbers mean?

Like any other vehicle component, the shock absorber has certain performance characteristics. They play a significant role in the process of driving a car, its obedience to driving, on the comfort of the trip and its safety.

braking distances

The operation of the damping device affects the speed of acceleration and deceleration of the car. If we consider the state of the car at the start, it turns out that when accelerating, the load on the rear wheels first of all increases and decreases on the front wheels, i.e. reduces the strength of their adhesion to the road surface. Braking is accompanied by opposite loads. Ideally, in both situations, the body should maintain its natural horizontal position.

Efforts will be directed precisely at stabilizing the position of the body. But dampers different in design and type of filler will work differently, at different speeds.

For clarity, we can give an example: at a distance of ten meters in front of the car, an obstacle suddenly appears (a cat, a dog jumped onto the road, a person suddenly fell across the road, and little else can happen).

If the car is equipped with oil models, it is unlikely that it will be possible to avoid a tragic outcome. Gas-filled devices will significantly reduce the braking distance. The accident will end safely, and the driver will be able to boast of his experience and excellent reaction.

But even taking into account such reasoning, experts do not recommend installing gas-filled models on used, especially domestic cars - destructive processes in such cars are immediately activated.

the ability of a shock absorber to dampen vibrations on rough roads

We have already mentioned that the most important requirement for shock absorbers is the ability to dampen body vibrations while driving. Those. A high-quality shock absorber should ensure constant contact between the road surface and the wheel surface, this will prevent the possibility of losing control of the car.

In the event of a serious difference in the height of the road surface (bumps or dents), the wheel should go around it as gently and quickly as possible, clearly returning to contact with the road surface.

Since oil-filled devices are slower, it will be difficult for them to provide full vibration damping on poor quality roads. Off-road driving with such cars should be avoided, trips on bad roads are fraught not only with discomfort, but also with rapid wear of shock absorbers.

shock absorber stiffness, how it behaves in tight corners

The situation with the displacement of loads, but only on the sides of the car, will occur during the execution of maneuvers by the car, for example, when passing a sharp turn.

Stiffer, gas-filled devices are capable of faster response, with increasing pressure inside the shock absorber, the response speed increases. They give rigidity to the suspension, at high speeds this is expressed by a decrease in body vibrations.

The same is true when making a sharp turn - a hard and fast-acting shock absorber will have time to compensate for the resulting loads and passengers will feel them to a lesser extent.

The installation of such high-speed damping devices is carried out on high-speed cars, such as sports, all-wheel drive and off-road vehicles.

Among the best representatives are the MonoMax series with increased strength and pressure and the adjustable Kayaba - AGX models.

Shock absorbers and working substance

If we take into account the type of working filler, then all models are usually divided into:

• gas
• oil
• gas-oil

If the answer is subjected to a logical analysis, then it will change somewhat, because oils and gases are used as a working substance in shock absorbers.

The cases of gas models are filled with inert gases, more often with nitrogen. It is pumped under a pressure of 2 - 3 atmospheres. The working space of oil-powered models is filled with hydraulic oils and air.

Dampers and number of pipes

In accordance with the design features, shock absorbers are divided into several types: single-tube and double-tube.

oil shock absorbers pros and cons

Let's start with the simplest option - hydraulic two-pipe. Its cost is not high, but it does not differ in stability of work.

This type is distinguished by the location of the working cylinder inside the housing. The body is a cylinder filled with some oil. Working in compression, the piston located inside the cylinder moves down, displacing the oil filler through the valve.

The air at the top of the cylinder is compressed. When the piston rebounds, it makes a reverse movement, the oil returns from the body through the return valve, passes into the working part of the cylinder.

The design and principle of its operation are quite simple, but simplicity does not always guarantee sufficient efficiency - in the process of repaying one energy, another is formed, the compensation of spring vibrations is accompanied by the release of thermal energy, which leads to heating of the oil and a change in its viscosity parameters.

Oil heating is fast and cooling slow, heating and constant oil movement with air access often cause foaming. There are no methods to combat this phenomenon. Sometimes they try to get rid of the problem by filling a new shock absorber "to the eyeballs", i.e. up to maximum occupancy.

But such actions will not lead to anything good, the oil will still look for a way out, as a result, the shock absorber will most likely fail. It turns out that aeration is an incurable disease of oil shock absorbers.

gas shock absorbers pros and cons

gas single pipe

This type is distinguished by a special design that provides for complete isolation of the oil from the gas filler.

These models are made up of:

• corps
• stock
• piston connected to the rod and equipped with reverse and forward stroke valves
• float piston that separates gas from oil

Of the significant differences, the absence of a working chamber should be mentioned, the body acts as its role. Separation into chambers occurs with the help of a float piston.

The lower part of the body is filled with nitrogen under high pressure. In the upper part there is oil, it is in it that the piston moves with the rod.

Since there is no working chamber in the design, the direct stroke valve is located directly near the rebound valve, on the piston.

The design of single-tube models has allowed to increase the volume of gas and oil, while the size of the shock absorber has not changed. Such design improvements saved the device from heating. Exclusion of contact between gas and oil prevents the aeration process, i.e. foaming oil.

Among the shortcomings of such models should be noted:

• change in hardness depending on the temperature of the gas,
• an increase in temperature increases the rigidity of the suspension
• an accidentally formed dent in the body will cause the shock absorber to jam, i.e. he will fail, fortunately, such precedents do not happen often.

gas-oil shock absorbers, pros and cons

Representatives of this species are known as gas-oil. Their design is similar to that of hydraulic models. The difference is that the cavity is filled with gas, usually nitrogen is used.

The gas accumulates pressure and prevents the oil from foaming. But it was also not possible to get rid of the heating problem in this way.

When buying a gas-filled shock absorber, it differs from a hydraulic shock absorber in terms of the stem - gas pressure tends to squeeze it out.

changelings

You should also remember about the shock absorber of a special design, the so-called. changeling. It differs in that it is installed upside down. If conventional shock absorbers are characterized by the direction of the stem strut upwards, then here the stem is directed downwards, its fastening is made to the strut body.

The pseudo-rod has a large thickness, is located on top. Such a device works due to the presence of several plain bearings. Among the advantages of the design, a significant reduction in the vertical and lateral load on the rack should be noted.

Riding style, how it affects the choice of shock absorber

Given the fact that different types of shock absorbers have slightly different characteristics, the choice should take into account the driving style that the motorist prefers.

If the plans include a quiet movement, then you should not bother too much - oil shock absorbers will be enough. Although there is an opinion that such models serve less, no official confirmation of this version has been received.

If the driver prefers an aggressive, sporty style, then it is best to give preference to models from special series, such shock absorbers are distinguished by an increase in compression and rebound forces.

This improvement allows you to get increased stability of the car when driving at high speed, in particular - when cornering. But moving in a calm mode will become less comfortable.

Fans of an aggressive sporty driving style can also use shock absorbers of high rigidity with adjustable parameters. The positive point is that such models have very high strength and reliability.

If the car is used for infrequent and short trips, then buying expensive shock absorbers is not necessary at all. For example, QH or AL-KO, or similar, is quite enough.

How to check the condition of the shock absorber on your car

Experienced drivers claim that the main signs of the health of shock absorbers are:

• obedience to car control
• noise level in the cabin
• no shaking and vibration while driving

At the same time, shock absorbers affect the speed of acceleration of the car, give a smooth ride, braking, cornering, overcoming descents and ascents.

They eliminate vibration, the increase of which can lead to wheel slip in extreme conditions, i.e. their action is aimed at increasing the safety of movement along the highway and minimizing the threat of accidents.

But, unfortunately, any part of the car wears out over time and needs to be replaced. The question arises: by what symptoms can a motorist determine a malfunction of a shock absorber.

It is possible to make a diagnosis yourself:

• determine if there are liquid leaks on the body (they should not be in good condition)
• by pressing on each of the corners of the body, the car should be rocked, as a response, only one return movement should occur, while the car should return to its normal position
• in the event of a malfunction of the shock absorbers, knocks will be clearly heard when the car is rocking

Such a simple test will reveal the malfunction, and therefore the onset of the time to replace it.

In order not to make a mistake when choosing shock absorbers, consider:

• many models are designed for certain brands of cars, so it is advisable to study the catalogs that are available in specialized stores
• type of previously used models
• preferred driving style
• the condition of the roads on which you have to travel in most cases
• cost, especially if the replacement will be carried out on a used car
• replacement of oil shock absorbers with gas ones, or vice versa, must be carried out on both axles at the same time, otherwise there is a risk of significant changes in the behavior of the car

None of the distributors can guarantee the quality and long service life of shock absorbers if they are installed on a car with a faulty suspension, without anthers and fenders, and the installation itself is carried out in violation of technology.

Sooner or later, every motorist is faced with a problem - what shock absorbers to replace the used old ones. The domestic shock absorber market is so diverse that it is easy to get confused in the abundance of manufacturers. And driving a car with faulty racks is not only not pleasant, but even risky - the car becomes uncontrollable, does not hold well on the roadway, constantly leads to the side, and the efficiency of the braking system is noticeably reduced.

Yes, and what to do, there used to be conventional hydraulic (oil) shock absorbers, and work colleagues recommend installing modern ones - gas ones. Some domestic motorists prefer to change shock absorbers immediately after buying a new car. How expedient it is, which shock absorbers are better - gas or oil, or maybe there is an alternative to both - today we will figure it out, based on our own driving experience and expert advice.

Why are they even needed...

This opinion is shared by some domestic motorists, arguing that shock absorbers are not needed, the main thing is springs. They, in their opinion, support the body of the car while driving, soften the effect on the car of all road irregularities. Yes, indeed, maintaining the body is the prerogative of the springs, and shock absorbers serve to reduce the amount of vibration of the springs and make them move smoothly. If only springs were installed on a car, then you would feel in the interior of such a car during even a slow movement, like a toy on a spring. In this case, the safety and good adhesion of the car's wheels to the road surface would simply have to be forgotten.

Hydraulic (oil) shock absorbers

Almost all passenger cars are equipped by domestic automakers with hydraulic (oil) shock absorbers. Let me remind you that earlier either friction or band shock absorbers were installed on cars.

Modern hydraulic struts are a double-acting system. It reduces the amplitude of suspension oscillations, both when it is fully compressed, and during its relaxation. This is achieved due to the oil, which, moving from one part of the shock absorber to another, takes on the resistance of the springs, thereby extinguishing their destructive force. The hydraulic shock absorber consists of a working cylinder, a rod with a piston, a compensation chamber, a guide sleeve and a damping fluid - oil.

The main disadvantage hydraulic struts is the presence of an air mixture in the compensation chamber. In the case when there is a low level of air in the chamber or it is absent at all, the effectiveness of the shock absorbers is zero. Otherwise, when there is too much air, the shock absorber will also not cope with its duties - it will simply fail (compress and decompress without resistance).

Also a negative feature of oil shock absorbers is their poor heat dissipation. During a long ride, due to poor cooling conditions, the oil in the shock absorbers overheats, thereby losing its binding properties, which means that the efficiency of the struts also decreases. When driving on poor quality roads, even at low speed, the car body begins to rock a little - this is not at all dangerous, more unpleasant.

It is not recommended to drive fast on bad roads in a car that is equipped with hydraulic struts. Due to the frequent and sharp movement of the piston, an intense field is created on its working surface, which contributes to the formation of cavitation bubbles - in a word, it can cause foaming oil.

In this case, the oil, mixing with air bubbles, turns into an emulsion, which leads to a decrease in the viscosity of the oil, as a result of which the shock absorber generally fails and ceases to cope with its duties.

To the benefits This type of shock absorbers can undoubtedly be attributed to their cost - the most affordable shock absorbers on the market, rather small in size, resistant to external negative factors.

Gas shock absorbers

A few years ago, soft hydraulics were replaced by modern - gas-filled ones. They work harder, but they are more stable and have a longer service life.

Unlike their counterparts, the compensation chamber of these shock absorbers is filled not with ordinary air, but with gas that is pumped into it under very high pressure - up to 28 atmospheres. In addition to this, in order to isolate the gas from the oil, the chamber was separated by a special membrane. The use of this technology has reduced the likelihood of oily liquid foaming to a minimum - after all, the higher the pressure in the oil, the higher its binding properties and its boiling point.

Due to the high pressure, the shock absorber piston is always under pressure. This makes it possible to respond much faster to the shortcomings of domestic roads. Moreover, a single-tube shock absorber, unlike a hydraulic two-tube one, cools better, therefore, it works more stable and copes better with its duties.

Gas-filled shock absorbers are stiffer than oil-filled shock absorbers. Basically, they are equipped with cars of athletes and those motorists for whom a quiet ride is not to their liking.

Another advantage gas shock absorbers is the ability to install them in different directions (both horizontally and vertically, and at different angles of inclination). Recall that hydraulic installation in such positions is strictly prohibited.

To the disadvantages of gas-filled shock absorbers can be attributed to their rather high cost, complexity of production, less comfort and rather large loads on the car body. The latter feature negatively affects the condition of the body, reduces the strength of all metal parts, bearings and ball bearings fail faster.

Gas or oil?

Let's start with the fact that there are no bad and good shock absorbers. It all depends on the professional skills of the driver, the ability to maintain the car, its condition. And a lot depends on the condition of the road surface.

As experienced motorists say, each road has its own shock absorbers.

Each motorist, putting this or that model of shock absorbers, seeks to increase the comfort and controllability of the car. But be that as it may, these two indicators are opposite to each other - improving one of them, we automatically worsen the other. Each car enthusiast has their own driving style and opinion on the level of comfort and stiffness of the suspension - the level of suspension stiffness that suits one driver may cause resentment in another.

Therefore, if familiar motorists stubbornly advise certain shock absorbers, saying that gas-filled struts are better than oil ones, you should not agree with them. Yes, indeed, they do a good job of their duties, but gas shock absorbers can show their advantages only during sports competitions. Looking at the driving style of "ordinary" motorists and the condition of our roads - hydraulic shock absorbers are what you need.

On the side of hydraulics is their cost- oil shock absorbers are an order of magnitude lower than gas-filled ones. As for gas shock absorbers, on their side, of course, the best level of control.

Imagine a picture - you eat and in front of your car, a pedestrian crosses the road. You, of course, slow down - the car stops a few centimeters from it. If your car had hydraulic struts, then the pedestrian was now somewhere in the area of ​​\u200b\u200bthe rear axle. Unlike hydraulics, cars with gas-filled shock absorbers have shorter stopping distances. You should not put gas shock absorbers on old cars, in particular on domestic models - a year of driving on such shock absorbers will completely destroy it.

So the choice is yours!

A very popular question among motorists is which shock absorbers are better: gas or oil, or gas-oil? And he is interested not only in lovers of a comfortable ride, but also in those who consider themselves to be "racers". In fact, shock absorbers provide many important parameters of the car, and above all - handling and directional stability.

Why do we need shock absorbers in a car, how they are arranged and work, what types of shock absorbers are and what are their advantages and disadvantages - the answers to these questions will help you make the right choice among a large number of manufacturers of these products on the Russian market.

At the end of the article, as usual, you can watch a video in which the author tells and shows which shock absorbers are better to choose (gas, oil or gas-oil) and how they differ from each other.

A shock absorber is an integral part of what provides comfort in the car body (sprung mass in technical terminology). The opposite of this term can be clearly illustrated with an old village cart on wooden wheels with a metal rim. It is easy to imagine how the passengers in such a wagon shake when driving on a rough dirt road.

To smooth out this shaking from potholes and potholes (or in technical terms, to damp vibrations in the vertical plane arising from road obstacles) is the main function of shock absorbers. Schematically, the shock absorber can be represented as a spring located between the wheels of the car (the tire, by the way, is also a kind of spring in this diagram) and the body.

In general, to assess the response to vertical impacts of the road, a car can be represented as a mechanical system consisting of many weights, springs and friction knots, interconnected in a complex way and providing the required smoothness. And shock absorbers play an important role in this scheme.

The principle of operation and the main types of shock absorbers (oil, gas, gas-oil)

You can illustrate the principle of the shock absorber with a simple example (see the pictures above):

• The lower part of the spring-loaded suspension strut is connected to the wheel through the shock absorber rod, and the upper part is connected to the car body.
• The impact from unevenness through the wheel is transmitted to the rod, which moves the piston inside the cylinder.
• There are two bypass valves in the piston (simplified - holes of different diameters), which allow almost incompressible oil to pass at a higher speed when the rod (and hence the wheel) moves up, and at a lower speed down.

Thus, the hydraulic part of the shock absorber works as a conditionally soft spring for compression, and a hard one for tension (“rebound” in technical terminology).

The mechanical spring in the figure is shown to a greater extent for clarity, but in practice it expands the possibilities of settings and serves as a kind of limiter when the shock absorber hydraulic cylinder fails.

The definition of "oil shock absorber" implies that only hydraulic oil is used as a working material in the cylinder. The dynamics of the oil shock absorber is entirely determined by the work (performance) of the bypass valves.

To expand the dynamic range and adjustment possibilities of oil shock absorbers, a kind of gas "cushion" was invented. The fact is that gases, unlike liquids, are compressed, and non-linearly (not proportional to the movement of the rod). This means that being "attached" to the "oil" part of the cylinder, they will make the dynamics of such a system richer.

The figure below shows a simplified design of a single-tube gas shock absorber.

Scheme of a single-tube gas shock absorber

It is clear that without the lower (gas) part, it becomes oily (only the squeezed out excess must be put somewhere, but more on that below).

And since shock absorbers filled exclusively with gas are not yet found on production cars, it is more correct to call such a design a “gas-oil shock absorber”.

For oil and gas-oil shock absorbers, the working cylinder of the device is usually two-pipe:

1. In oil shock absorbers, excess oil comes out into the second (larger diameter) pipe through additional valves during compression, “pressed” in the second pipe by air.
2. In gas-oil shock absorbers, a gas cushion (usually nitrogen under pressure) is pumped into the second pipe instead of air.

Sometimes the gas cushion in gas-oil shock absorbers is structurally located on the side of the cylinder.

Main types of shock absorbers

In addition to a narrower range of elasticity characteristics, the cushion of air in the oil shock absorber does not effectively dissipate the heat energy released during intensive work, which sometimes leads to the boiling of the working fluid. In a gas-oil shock absorber, this effect is excluded.

Like any hydraulic technique, shock absorber cylinders require high-precision (precision) machining, a complex system of valves and seals, and for gas-oil shock absorbers this system only becomes more complicated.

Since the gas-filled part of the shock absorber significantly expands the dynamic range of the system, in general, the device assumes a softer response to road bumps than in the "oil" version - it's like a series connection of two springs: soft and hard, which in total gives a softer response than just a hard one. spring.

Interestingly, manufacturers do exactly the opposite and adjust gas shock absorbers to a greater extent for an aggressive driving style and sports cars. More precisely, on well-paved roads, the gas dampers are set to a softer response from vertical influences, and on bad roads with the same settings they become stiffer.

It must be emphasized that in sports driving, smoothness is far from in the first place: parameters such as handling and directional stability are much more important, which gas shock absorbers provide better than oil ones.

The Russian market of shock absorbers for foreign cars with a share of the main players of 10 percent or more, according to the Autoinstruction magazine, is represented by several well-known companies (diagram in the figure above):

• KYB (Kayaba) - 35%;
• Boge (God) - 16%;
• Fenox (Phenox) - 15%;
• Monroe (Monroe) - 14%;
• Bilstein (Bilstein) - 11%;
• Other firms - 9%.

It is interesting that during a survey of service centers conducted by the publication "Kuzov", for the recommendations of professionals on the choice of a manufacturer of high-quality shock absorbers, the picture turned out to be somewhat different.

With firms such as KYB, Bilstein, and Boge leading the way, Monroe is only 5% of the time pros recommend it, even though the firm's market share is nearly three times higher. And they practically do not recommend the Belarusian brand Fenox, the share of products of which is very significant - 15%.

To figure out which shock absorbers are better to put, it is necessary to briefly dwell on the characteristics of the leading players in the Russian market.

• KYB(Kayaba) - the products of the Japanese concern are popular not only in Russia, but also in Europe due to their high quality and reliability at a relatively low price level. Shock absorbers of this company can be found on the conveyors of well-known European automakers. The gas-oil shock absorber of the Ultra SR series is especially popular with Russian sports driving enthusiasts;
• Bilstein(Bilstein) is a world famous German company that has been producing shock absorbers for over 50 years. It was here that the design of a single-tube gas-filled shock absorber was developed. Bilstein products are installed on European premium brands: BMW, Porsche, Mercedes, Ferrari, Maseratti, Jaguar;
• God(Boge) - the brand belongs to the concern ZF Friedrichshafen AG (Germany) - one of the world's oldest manufacturers of shock absorbers. Recently moved to another well-known brand - SACHS and now the same type of products are produced under two trademarks. The concern's products cover more than 90% of the range of world automakers. On the Russian market, a 1-year warranty is provided, regardless of mileage;
• Monroe(Monroe) is an American company whose products are probably the most famous in Europe and are intended for 99% of the world's makes and models of cars. Monroe's latest Sensatrac series gas shock absorbers deliver superior handling performance and instant response to changing driving conditions;
• Koni(Horses) - shock absorbers - this is the only product of the Dutch company for almost 70 years. The main distinguishing feature of Koni shock absorbers is the ability to adjust the stiffness parameters, adapting the car both to external conditions and to the individual characteristics of the driver and the manner of driving the car.

But are all major manufacturers of shock absorbers widely represented on the Russian market? The figure below shows the top six players in this market in the US according to a survey by Ranker.

The first three consists of participants in the Russian rating. But the products of the American fox racing and Swedish Ohlins specific - it is designed for motorcycles, ATVs and SUVs. American Rancho Suspension in Russia is quite well-known and specializes in the supply of products for pickups and large SUVs popular in the USA. A few years ago, Rancho was acquired by Tenneco, which in turn owns the Monroe trademark.

Thus, the first three manufacturers of shock absorbers with a high reputation for Russia are KYB, Monroe And Bilstein.

As for the objective characteristics provided by shock absorbers and affecting the safety, handling and comfort of the car, they look like the following according to the manufacturers themselves.

Braking distance at a speed of 40 km / h:

• Bilstein - 8.0 meters;
• Monroe - 8.5 meters;
• KYB - 9.0 meters.

The differences are quite significant, if you remember that in a critical situation, centimeters of braking distance are important.

Rear axle drift 90° (tight turn mode):

• Bilstein - 59 km / h;
• Monroe - 52 km / h;
• KYB - 48 km / h.

Tests for smoothness (characteristics closely related to the subjective feeling of comfort) and directional stability are carried out in relation to each specific car model, therefore, it is possible to compare shock absorbers from different manufacturers only for specific cars.

It is interesting that such tests sometimes give paradoxical results: venerable firms can lose to outsiders, both in individual indicators and in aggregate test results.

And yet, which shock absorbers to choose? Given the variety of designs, a wide range of loads and significant differences in the characteristics of different models of cars, as well as individual characteristics of driving style, monosyllabic answers to this question should not be expected.

It is necessary to rely, first of all, on the recommendations of the car manufacturer, both in terms of characteristics and in terms of shock absorber manufacturers. If the owner wants to change the dynamics of the car due to shock absorbers (or there is no way to follow the manufacturer's recommendations exactly), general considerations on how to choose shock absorbers for a car can be formulated as follows:

Selection by type (oil, gas, gas-oil):

• For those who prefer comfort, a quiet ride, reliability and affordable prices, two-pipe oil shock absorbers are suitable;
• If you want comfort requirements to be combined with improved cornering dynamics, and the cost and reliability of the part are in a reasonable range, then twin-tube gas-oil shock absorbers are the right choice;
• Single-tube gas shock absorbers are designed for aggressive driving enthusiasts who prefer the handling of the car to a smooth ride.

By the way, the age of the car is also an important factor in making a decision. It is hardly advisable to install expensive gas shock absorbers on cars of venerable age with high mileage: the elastic characteristics of the suspension and body strength indicators deteriorate over time, and instead of the expected one, you can get the opposite effect.

Choice by manufacturer (which company shock absorbers are better):

• If the car belongs to the budget segment, and there is no need to test it in sports modes, and funds for maintenance are limited, shock absorbers from the Russian company SAAZ or the Belarusian Fenox may well be suitable;
• Those who appreciate quality and are ready to pay for it (even if the car does not belong to expensive foreign cars) should pay attention to the products of KYB, Monroe and Boge (Sachs);
• The products of Bilstein and KONI (the aristocrats in the world of shock absorbers) are recommended by experts for both sports driving enthusiasts and owners of premium cars.

And, of course, you need to beware of fakes: if the price for Bilstein products in the store is the same as for the Belarusian Fenox, then something is wrong with such a seller (and not with respect to Fenox). And the recipe for verification is the presence of a certificate of conformity, a warranty card and the correspondence of a unique serial number to the data on the official website of the manufacturer.

Differences between gas, gas-oil and oil shock absorbers, their pros and cons

The nature of driving depends on the shock absorber, so its choice should be taken seriously.

Let's start with the fact that this part is correctly called the "shock absorber", and not the "rack". Any suspension specialist will tell you that this is the last thing drivers think about. In fact, among the most noisy, gleaming and simply visible parts of a car, these inconspicuous components are the most underestimated. Their function is to maintain traction during acceleration, braking and cornering, while still providing comfort to passengers in the cabin. Agree, this is important. Although shock calibration is the last thing done during suspension debugging, it is they who are responsible for how the car's chassis will be. So, we have prepared a classification of the most common types of shock absorbers:

Single tube dampers

Where: Audi A4, Mazda MX-5 Miata

The body of a single-tube shock absorber is divided into two chambers: oil and gas. The piston with the rod moves down and creates a balancing force. During compression, oil is forced out of the stroke into the housing. When rebounding, the shimstack controls fluid flow. The gas in the chamber (most often nitrogen) is compressed and takes all the impact on itself, and only then does the oil begin to pass. The balancing force is determined by the shape, size and number of washers on the shock piston, piston diameter, body diameter and gas pressure.

Twin tube dampers

Where: Cadillac CT6, Chevrolet Impala, Ram 1500

As the name implies, shock absorbers of this type consist of two concentric cylinders. The inner cylinder is filled with oil and also houses the piston and rod. As in single-tube shock absorbers, a rod with a piston moves inside the cavity, on which valves are mounted that determine the forces of both rebound and compression. An additional foot valve directs oil into the outer cylinder (reservoir) during compression, increasing the damping factor. During rebound operation, oil returns to the main chamber reservoir through the control valve. The outer cylinder is partially filled with compressible gas, which compensates for the released volume of the rod and contributes to the fact that oil from the outer cylinder enters the inner cylinder during rebound operation. The balancing force is determined by the same factors as in monotube dampers, but with the additional influence of the bottom valve. The two-tube shock absorber is adjusted by adding or removing washers.

Internal bypass damper

Where: Ford F-150 Raptor

Fox twin-tube shock absorbers in automobiles carry fluid through multiple bypass pipes. The working fluid bypasses the piston and flows through the holes into the inner cylinder, filling the area behind the piston. Some of the oil also passes through the piston shimstack and through the foot valve when compressed. The size, position and adjustment of the holes progressively increase the damping factor when the suspension compresses or rebounds. When the stem passes through the last bypass port, the working fluid preferentially passes through the shimstack attached to the stem, greatly increasing the damping force. The foot valve plays an important role during the entire compression stroke and regulates the flow of the working fluid entering the external reservoir. This provides stable control of compression resistance and reduces cavitation (air pockets in the oil) when driving at high speed.

(Note to the figure): “If you increase the elasticity coefficient before you drive the car, you can predict in advance what will happen. With magnetorheological shock absorbers, even after many years, I still learn a lot, still experimenting. I keep finding new things." Mike Hurley, Chevrolet Performance Engineer. He has been debugging magnetorheological shock absorbers since they were used in the 2003 Cadillac XLR..

Magnetorheological shock absorbers

Where: Cadillac CTS-V, Chevrolet Corvette, Ferrari 488GTB, Lamborghini Huracan

Magnetorheological shock absorbers do not have damping factor valves. The movements of the wheels and body of the car are controlled by changing the viscosity of the oil. And although the design of shock absorbers is relatively standard (the rod at the end of the piston moves inside a cavity with hydraulic fluid), the principle of their operation is different. The new generation magnetorheological shock absorbers use two electromagnetic coils located in the piston. It is they who generate the local magnetic field. The hydraulic circuit inside the shock absorbers contains tiny ferromagnetic particles that are randomly distributed until an electric current passes through the magnetic coils. The current passing through the magnetic coils creates a magnetic field that distributes the particles in rows. As the orientation of the magnetic particles changes, the viscosity of the liquid also changes. When the pressure exerted on either side of the piston is strong enough to break these rows of particles, the fluid flows through the passages, setting the piston in motion. The particle alignment force is proportional to the strength of the magnetic field, so changes in the current strength of the coils lead to a change in the damping force.

Shock absorber equipped with spool valve

Where: Chevrolet Camaro ZL 1LE, Chevrolet Colorado ZR2