The construction of the shock absorbers may be different but the principle of operation is the same.
• The up and down movement of the shock absorber is controlled by the suspension spring wound around it or within it.
Whether it is beam (fixed) axle suspension or independent (nonfixed) suspension, the fundamental principle of a suspension damper (misleadingly called the shock) is to dampen the road shocks for the comfort of the occupants in the car, hence the unofficial name the shock absorber.
When they are worn out it becomes hard for the driver to maintain the vehicle on the road due to continuous oscillations that affect the steering angles.
The construction of the shock absorbers may be different but the principle of operation is the same. Whether it is hydraulic operated or gas-operated, the essence is to pump the hydraulic fluid or gas through small orifices from one chamber to the other when a vehicle hits uneven road surface. The rate at which the fluid moves from one chamber to the other determines how the ride will be felt. The up and down movement of the shock absorber is controlled by the suspension spring wound around it or within it. The weaker the spring the more the up and down oscillations, the harder the spring the harder it is for the damper to travel which translates to a harder ride.
From the above explanation, it is evident that every shock absorber is engineered for a certain purpose. From a comfortable smooth ride for passenger vehicles to a hard ride for cargo vehicles. The road wheel bearings, the shock mounts and the mounting points are all considered when the vehicle is being manufactured.
The problem comes in when you want to change the above ride by larger margins without factoring in all the above-mentioned considerations.
For instance, someone buys a car meant for light purpose but wants to use it for commercial use. They then install heavy-duty springs to the original shocks to refrain them from natural oscillations. As much as this would work for the new purpose, the impact could be felt somewhere else.
The new heavy-duty springs limit the shock absorber from downward compression. This has a direct impact on the wheel bearings. The stresses that could have been taken by the dumper are now being directly subjected to the wheel bearings. The results are reduced wheel bearing lifespan.
The direct impact from the road is also subjected to the brackets and mounting points where the shocks are bolted. Usually, these points are not reinforced for had impacts. Changing to heavy-duty springs directly impacts these points and sometimes would weaken them resulting in cracked mountings points that would lead to severe damage.320mm motorcycle rear shock absorber with spring
Most front shocks for personal cars come with a top-mounted bearing on the shock mounting to allow for shock swivel when cornering, when these bearings are subjected to a lot of impact the bearing gets damaged making the steering system to be harder especially on low speeds. In the case of the 4x4, a transversely mounted steering damper may also leak out and make it difficult to drive the vehicle.
Heavy-duty springs tend to push the shock in an upward direction all the time. A good example is when going through a bump with an empty car fitted with this kind of springs. The rear of the car tends to spring upward on rebound motion even before the full bound motion has been completed. One of the chambers in the shock is supposed to resist oil passage through the orifice for a smooth transition between bound and rebound which gives the vehicle a smooth passage on the bump. When the rear of the car is rapidly sprung upwards, the receiving chamber may be punctured which would result in leakage of the hydraulic fluid/gas from the chamber rendering the shock unfit for its duties.
Another common side effect of heavier springs on standard shocks is the transferred impact to the vehicle body. Tailgates, doors, bonnets and other structures may fall out of original tolerance which will allow more play and noises due to high road impacts.
As we may all now understand, the principle of operation of a standard shock is by pushing the fluid from one chamber to the other through small valves to cushion the impact, the process involves heat generation. The more repeated you do it for prolonged periods the more heat you produce and the higher the chances you create for the seals to get worn out due to heat. Technically driving on the extremely bad road for prolonged periods heats the shock and some cooling may help it to function well.
The best way to cool the shocks is by spraying cool water on them or methylated spirit after a long drive on a bad road. This cools the oil or gas inside giving them more working hours in such conditions.
In most cases, shocks have failed to work when they are extremely hot.
Original shocks always give better comfort but when the soft ride has to be traded with a harder ride then several considerations m