Gas struts are one of those components you interact with every day without giving them a second thought — until they stop working. Whether it's a car boot that no longer holds itself open, a kitchen cabinet lid that drops without warning, or an ottoman bed that takes two hands to lift, a failing gas strut makes itself known quickly. This guide covers everything you need to know: what gas struts are, how they work, the different types available, where they're used, and how to know when it's time to replace them.
What Is a Gas Strut?
A gas strut — also called a gas spring, gas lift, or gas shock — is a device that uses compressed gas to produce a controlled, smooth pushing force. In practical terms, it does the same job as a mechanical spring, but with a key advantage: the force it delivers is much more consistent throughout its travel, and it can be calibrated precisely for the load it needs to support.
At its most basic, a gas strut is a sealed cylinder containing pressurised nitrogen gas and a small amount of hydraulic oil. A piston rod moves in and out of the cylinder. When compressed, the gas resists and stores energy. When released, it pushes the piston back out — lifting, holding, or cushioning whatever it's attached to.
Browse our full range of universal gas struts — available from 100N to 2000N and 150mm to 1000mm.
How Do Gas Struts Work?
The operating principle is straightforward. Inside the sealed steel cylinder, nitrogen gas is held at high pressure — typically between 100 and 200 bar, depending on the application. A piston sits inside the cylinder, and the piston rod passes through a sealed end cap.
When you push the rod inward (compressing the strut), you're working against the pressure of the nitrogen. That energy is stored. When you release it, the gas expands and pushes the rod back out with a consistent force — this is what holds a car bonnet open or keeps an ottoman lid raised.
The small amount of hydraulic oil inside the cylinder serves two purposes: it lubricates the piston seal to prevent wear, and it provides a degree of damping, which gives the movement a smooth, controlled feel rather than a sudden snap.
Types of Gas Struts
Gas struts vary primarily in their end fittings and their intended application. Here's a breakdown of the most common types:
The most common fitting type. A ball on the strut end clips into a socket bracket on the frame. Easy to install and remove — most replacement struts use this fitting.
A looped end that bolts through a fixed bracket. Common on heavier applications such as industrial lids, large storage units, and some automotive uses. More secure under higher loads.
Designed to fit a wide range of standard applications. Supplied with ball-socket fittings and compatible with the majority of UK ottoman beds, cabinets, and storage units. Available from £6.90.
Manufactured to match the exact dimensions, force rating, and mounting points of a specific vehicle make and model. Used for bonnets, boots, and tailgates where OEM fitment is required.
Rated at higher Newton forces — typically 800N and above — for industrial lids, large hatches, and equipment covers. Built with thicker cylinder walls and reinforced seals.
Constructed from marine-grade stainless steel for use in outdoor, coastal, or high-humidity environments where standard steel would corrode. Coming soon to Autorce.
What Are Gas Struts Used For?
Gas struts appear in more places than most people realise. Any hinged or sliding panel that needs to open smoothly, stay open without support, and close gently is a candidate for a gas strut. Common applications include:
| Application | Typical Newton Range | Notes |
|---|---|---|
| Ottoman bed lift | 600N – 1200N | Two struts per bed; matched to mattress size |
| Car bonnet | 200N – 400N | Vehicle-specific length and force required |
| Car boot / tailgate | 300N – 600N | Usually one per side; OEM dimensions critical |
| Kitchen cabinet lids | 100N – 300N | Lighter loads; shorter stroke typically needed |
| Garden storage box | 150N – 400N | Stainless steel recommended for outdoor use |
| Caravan / motorhome hatches | 200N – 500N | Corrosion-resistant fittings preferred |
| Workshop / tool chest lids | 400N – 800N | Heavier lids may require heavy duty rating |
| Industrial equipment panels | 500N – 2000N | Eyelet fittings common; custom lengths available |
How Long Do Gas Struts Last?
A quality gas strut in a standard domestic application — an ottoman bed, kitchen cabinet, or car boot — will typically last between 5 and 10 years under normal use. In automotive applications with frequent cycling, expect towards the lower end of that range. In low-use indoor settings, a well-made strut can last considerably longer.
Gas struts fail gradually rather than suddenly. The nitrogen pressure slowly escapes past the piston seal over time, reducing the lifting force until the strut can no longer do its job. The hydraulic oil can also degrade, causing the movement to feel jerky or uneven rather than smooth.
Signs Your Gas Struts Need Replacing
- The lid or panel no longer holds itself open — it drifts closed or drops
- You need to use more force to lift than before
- The movement feels jerky, uneven, or stiff rather than smooth
- The strut body is visibly bent, dented, or corroded
- Oil residue is visible on the piston rod or cylinder (seal failure)
- The end fittings have become loose or cracked
How to Choose the Right Gas Strut
Selecting the correct gas strut comes down to three measurements and one force calculation:
- Compressed length — the total length of the strut when fully closed, measured end fitting to end fitting
- Stroke length — how far the rod extends when the strut is fully open
- End fitting type — ball socket, eyelet, or threaded, matched to your mounting brackets
- Newton force — the lifting force required, calculated from the weight of the panel and the geometry of the mounting position
Newton force is the most critical — and the most commonly misunderstood — variable. Too low and the strut won't hold the panel open. Too high and it won't close properly. Our Gas Strut Calculator takes the guesswork out of this: enter your panel dimensions, weight, and hinge position, and it returns the correct Newton rating for your application.
For ottoman beds specifically, see our dedicated Ottoman Bed Gas Strut Size Guide which includes a quick-reference table by bed size.
Key Takeaways
- A gas strut uses pressurised nitrogen to produce a smooth, consistent lifting force
- They are used in ottoman beds, car bonnets and boots, kitchen cabinets, garden storage, and industrial applications
- Types include ball joint, eyelet, universal, vehicle-specific, heavy duty, and stainless steel
- Most domestic gas struts last 5–10 years; replace when the panel no longer holds open or movement becomes uneven
- Always replace struts in pairs on paired applications
- Use the Gas Strut Calculator to find the correct Newton force before ordering
Ready to find the right gas strut? Browse the full range or use our calculator to get an exact match.
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Frequently Asked Questions
A gas strut is a sealed cylinder filled with pressurised nitrogen gas and a small amount of hydraulic oil. A piston rod moves in and out of the cylinder, producing a smooth, consistent pushing force. Gas struts are used to lift, hold open, and gently close hinged panels — from car bonnets to ottoman bed lids to kitchen cabinet doors.
Gas struts work by storing energy in compressed nitrogen gas. When the strut is pushed inward (compressed), the gas pressure increases and energy is stored. When released, the expanding gas pushes the piston rod outward with a consistent force — this is what lifts and holds open a panel or lid. The hydraulic oil inside provides smooth, damped movement rather than a sudden snap.
Gas struts are used wherever a hinged panel needs to open smoothly, hold itself open, and close in a controlled manner. Common applications include ottoman beds, car bonnets and boot lids, kitchen cabinet lids, garden storage boxes, caravan hatches, workshop tool chest lids, and industrial equipment panels.
Gas struts vary mainly by end fitting and application. The most common types are ball joint (ball socket) struts — used in most domestic applications — and eyelet (clevis) struts, which are bolted through a bracket and used for heavier loads. By application, they divide into universal struts (suitable for a wide range of uses) and vehicle-specific struts (matched to exact OEM dimensions). Heavy duty and stainless steel variants are available for demanding or outdoor applications.
In most domestic applications, quality gas struts last between 5 and 10 years. Automotive struts that are cycled more frequently tend towards the lower end. Signs that a strut needs replacing include a panel that no longer holds itself open, increased effort required to lift, jerky or uneven movement, or visible oil residue on the piston rod.
You need three measurements — compressed length, stroke length, and end fitting type — plus the correct Newton force for your application. Newton force depends on the weight of the panel and the geometry of its hinge position. Use the Autorce Gas Strut Calculator to get an accurate Newton rating based on your specific setup.
It is not recommended. On any application that uses two struts — such as an ottoman bed or a tailgate — replacing only one creates an imbalance. The new strut will produce full force whilst the worn strut produces less, causing uneven lifting and putting additional stress on the new strut. Always replace gas struts in pairs.
