Shock absorbers are vehicle suspension systems that dampen the vibrations caused by driving on uneven terrain. The shock absorbers extend and retract to balance pressure and maximise the contact between your truck’s wheels and the ground. This contact enhances the control, stability and performance of your truck.
Shock absorbers also absorb the inertia created when applying the brakes and transporting imbalanced cargo. In New Zealand, quality shock absorbers keep buses stable when maneuvering the country’s undulating roads.
This article describes commercial vehicle shock absorbers and how they work, guiding you on what to consider when selecting shock absorbers for trucks & buses in New Zealand.
How shock absorbers work
While there are various types of shock absorbers, they all work under the same governing principle. Shock absorbers take the kinetic energy generated by the movement of your suspension system and convert it into thermal energy. The shocks then dissipate the thermal energy to the atmosphere as heat.
In its most basic form, a shock absorber consists of a piston and a fluid-filled cylinder. When your truck experiences a sudden change in terrain, its suspension system and springs begin to move. Your shock absorber’s piston is pushed into the fluid-filled cylinder to dampen the suspension system’s motion. This dampening fluid then heats up due to compression from the shock absorber’s piston.
The shock absorber slowly allows the hot dampening fluid to flow out of its cylinder through small orifices. The movement of fluid dissipates heat and slows down the vibrations of your suspension system; the release of dampening fluid extends the shock absorber’s piston to its original position.
Types of shock absorbers
The types of shock absorbers used in the heavy vehicle industry can be grouped into two categories based on their operational fluid. These are:
- Gas Charged shock absorbers
- Hydraulic shock absorbers
Within the above categories, shock absorbers vary by structure, design and application. Below is a brief explanation of the differences between gas and hydraulic shock absorbers.
Hydraulic Shock absorbers
These are the most common types of shock absorbers. The type of hydraulic fluid should withstand the typical load and driving regime of your truck.
Hydraulic shock absorbers are best suited for vehicles that experience significant variations in terrain, loads and driving conditions. They provide a slow and gradual response, ideal when moving at lower speeds. Most off-road trucks use hydraulic shock absorbers.
It is best to replace rather than repair faulty shock absorbers. To avoid delivery delays, order shocks from local suppliers of aftermarket parts for European trucks, providing high-quality yet affordable and readily available solutions for trucks and buses in New Zealand.
Gas Charged shock absorbers
Gas-charged shock absorbers are ideal for high-velocity truck and bus applications. They are commonly installed in on-highway buses and trucks that maintain high speeds over long distances.
Gas-charged shocks are filled with nitrogen and thus don’t suffer the risk of aeration. Gas shock absorbers respond faster to changes on the road than hydraulic systems – the rapid response is an advantage in on-highway settings, where it prevents challenges related to ‘brake dives’. Yet, it is challenging in rough terrain where its rapid response can create stiff, uncomfortable reactions.
All things considered, the choice of shock absorbers should suit the driving style and conditions. Shock absorbers are available in complete sets of aftermarket parts for European trucks; replacing all the shock absorbers together eliminates the risk of failure due to the imbalance and uneven wear of your suspension systems.