Gas Shock Absorber

All About the Gas Shock Absorber


 – Gas-Filled Damper: Role of the Damper

 – How the gas shock absorber works

 – Gas Shock Maintenance and Price

 If you are replacing your shocks, there are many choices in replacement shock types, and gas shock is one of them. To help you make an informed choice about this type of shock absorber, we’ll reveal its particular technology and benefits in this article.

 Gas shock absorber: role of the shock absorber

 Regardless of its technology, the role of the shock absorber is the same for all vehicles, and it is an essential element for road holding and the comfort of the occupants. A car’s suspension is made up of two distinct components:

 – The suspension spring (or its equivalent, the torsion bar) is a shock absorber: it interfaces between the unsprung mass (wheels, hubs, brakes) and the vehicle body. When the wheels impact the road’s irregularities, it compresses and “absorbs” the shock. It then releases this stored energy through oscillations whose frequency and amplitude gradually decrease.

 – The shock absorber prevents the spring’s oscillations by storing its energy and gradually releasing it; it then allows the wheel to remain in contact with the ground, thus improving road holding and the comfort of the vehicle’s occupants. Without the shock absorber, the spring and its oscillations would create a dribbling phenomenon. The wheel would jump on the road, and during a succession of consecutive shocks, the rebounds, and their accumulated energies would saturate it and lead the wheel to hit the suspension stop, seriously compromising the road holding… and the state of the passengers’ spine!

 How the gas shock absorber works

Gas Shock Absorber

 It is the same as the classic shock absorber: it contains oil. The shock absorber is a pump consisting of a shock absorber body in which a piston pushed by the shock absorber rod slides.

 The movement of the piston is opposed by the oil contained in a working chamber, which is forced through calibrated passages in the piston, thus slowing down its translation speed (there are passage valves for the compression and valves for the expansion of the damper).

 The oil thus laminated occupies an airtight space called the compensating chamber, the upper part occupied by a volume of gas.

 This is the specificity of the gas damper: if this gas in the conventional damper is air, in the gas damper, it is nitrogen.

 Please note: The pressure of this chamber (on average 25 bars) can sometimes be adjusted with an external valve (competition shock absorbers or motorcycle shock absorbers).

 Advantages of the gas shock absorber

 The gas shock absorber is robust and has many qualities:

 – By its reactivity due to the volume of gas, it gives an excellent road holding to the vehicle;

 – It is much less sensitive than the classic shock absorber to heating, allowing it to preserve its qualities whatever the operating temperature; this is due to the properties of the gas contained: it is nitrogen, which is a neutral gas whose volume varies very little with the heat, unlike air;

 – The gas pressure is often adjustable and is well suited to intense use or competition.

 However, its handling qualities sometimes handicap it of its relative hardness and discomfort. The price of its performance is that it can also be more expensive.

 Maintenance and price of the gas shock absorber

 Like a conventional shock absorber, it should be replaced when it loses its road-holding qualities, leaks, or becomes loose, especially in its mountings (these last two symptoms can be a reason for refusal at the technical inspection).

 The recommended replacement interval is 40 to 60,000 km.

Examples of prices

Gas shock absorber type

Price per unit (shock absorbers are replaced in pairs)


Classic gas shock absorber

from $55 to $80

All (internet, equipment manufacturers, dealerships, car centers…)

Adjustable gas shock absorber (hydraulic and gas pressure)

from $140 to $200

OEMs and competition workshops

Competition shock absorbers (as a set with the spring)

from $600 to $1000

OEMs and competition workshops

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