- Technical Guide
- Gas Spring Basics
- How to Choose Gas Spring Force
- How to Measure Gas Spring Length
- How to Select Tube/Rod Diameter
- How to Choose End Fitting
- Gas Spring Installation Guide
- Automotive Gas Struts
- Select Gas Struts with OE number
- Select Gas Struts without OE number
- Model compatibility
- Furniture Gas Springs
- Other Applications
- FAQ
Technical Guide
Welcome to the DampFlex Gas Spring Knowledge Center.
At DampFlex, we specialize in high-quality automotive and industrial gas springs, providing reliable solutions for your applications.
Our goal is to help engineers, designers, and technical buyers select the right gas spring for every project—whether it’s for precise force, correct dimensions, optimal rod diameter, or proper mounting.
Explore our guides and technical insights to ensure safety, performance, and long service life for your systems.
1️⃣Gas Spring Basics
A gas spring is a mechanical device that uses compressed gas to provide a controlled force for lifting, lowering, or positioning applications.
Key parameters of a gas spring include:
– Force (N): the pushing or lifting strength
– Extended Length (EL):the length from mounting hole center to mounting hole center when fully extended
– Stroke: the distance the rod travels during compression
– Rod Diameter: affects stability and load capacity
– Tube Diameter: affects internal pressure and durability
Understanding these basics is essential for selecting the right gas spring for your application.
2️⃣How to Choose Gas Spring Force
Introduction
Choosing the correct gas spring force is one of the most critical steps when selecting a gas strut.
If the force is too low, the object will not lift. If it is too high, it may be difficult or unsafe to close.
This guide explains how to calculate and select the proper force (measured in Newtons, N) for automotive and other applications.
What Is Gas Spring Force?
Gas spring force refers to the output force generated by the compressed gas inside the cylinder.
It is typically measured in Newtons (N). 10N is approximately equal to 1 kg.
Common examples:
10-80N → Micro gas springs
100N → Light cabinet doors
200–400N → Furniture applications (beds, storage lids)
300–500N → Automotive trunk or hood struts
800-1500N → Heavy Machinery
Key Factors That Affect Force Selection
Choosing the correct force depends on several factors:
1. Weight of the Object
The heavier the object, the higher the required force.
Examples:
Cabinet door: 2–5 kg
Storage bed: 15–40 kg
Car trunk lid: 10–25 kg
2. Mounting Position
Force requirement changes depending on installation angle and position.
Vertical installation → Less force required
Horizontal installation → More force required
Offset mounting → Changes leverage
This is one of the most common reasons for incorrect selection.
3. Distance from Hinge (Leverage)
The closer the gas spring is installed to the hinge, the higher force is needed.
Short distance → Higher force
Longer distance → Lower force
4. Opening Angle
Larger opening angles require more force to maintain stable support.
Basic Force Calculation Formula
A simplified formula used in many applications:
Where:
Weight in kg
Gravity ≈ 9.8 m/s²
In real applications, a safety factor is usually added.
Practical Selection Method (Recommended)
Instead of relying only on formulas, most professionals use this approach:
Step 1: Estimate weight of the lid/door
Step 2: Determine mounting positions
Step 3: Choose initial force range
Step 4: Test and adjust
For most projects, testing is essential to get the best performance.
Common Mistakes to Avoid
Choosing force based only on weight
Ignoring installation geometry leads to wrong results.
Using too much force
Hard to close
May damage hinges
Ignoring temperature effects
Gas spring force can change slightly in extreme temperatures.
Typical Force Reference Table
| Application | Recommended Force |
|---|---|
| Small cabinet door | 80–150 N |
| Kitchen cabinet | 100–200 N |
| Storage bed | 300–800 N |
| Car trunk | 400–700 N |
| Car hood | 500–900 N |
These values are for reference only and may vary by design.
When You Need Custom Gas Springs
Standard force may not always fit your application.
You may need customization when:
Unique installation geometry
Special load requirements
OEM replacement projects
European vehicle compatibility
Conclusion
Selecting the correct gas spring force requires considering weight, mounting position, and leverage—not just a single parameter.
A proper selection ensures:
Smooth operation
Longer product lifespan
Better user experience
Need Help Choosing the Right Gas Spring?
If you are unsure about the correct force or need OEM/ODM solutions, feel free to contact us.
We can support:
Force calculation
Drawing confirmation
Custom production
3️⃣How to Measure Gas Spring
Introduction
Choosing the correct gas spring is not only about force — length is equally critical.
Incorrect length can lead to:
Improper installation
Limited opening angle
Excessive stress on mounting points
Early product failure
In this guide, I’ll show you how to measure gas spring length correctly and avoid common mistakes.
1. Key Terms You Must Know
Before measuring, you need to understand two basic dimensions:
Extended Length (Center-to-Center)
The total length of the gas spring when fully extended, measured from the center of one end fitting to the center of the other.
Stroke Length
The distance the rod travels from fully compressed to fully extended.
Formula:
Stroke = Extended Length – Compressed Length
2. How to Measure Gas Spring Length
Step 1: Fully Extend the Gas Spring
Make sure the gas spring is in its fully extended position.
Do NOT measure when compressed.
Step 2: Measure Center-to-Center Distance
Measure from:
Center of one ball joint (or fitting)
toCenter of the opposite fitting
This is your Extended Length
Step 3: Measure Compressed Length
Compress the gas spring (carefully), then measure again:
Center to center distance
This gives you the Compressed Length
Step 4: Calculate Stroke
3. Example
Extended Length: 400 mm
Compressed Length: 240 mm
Stroke = 160 mm
4. Common Mistakes (Very Important)
Measuring End-to-End Instead of Center-to-Center
This leads to wrong installation dimensions.
Ignoring End Fittings
Different fittings (ball joint, eyelet, fork) affect total length.
Measuring While Installed
Angles and mounting positions can distort measurements.
Always measure the gas spring separately if possible
5. Special Notes for Automotive vs Furniture
Automotive Gas Springs
Usually exact match required (OEM standard)
Even small deviation can cause installation failure
Furniture Gas Springs
More flexible
But still requires correct stroke and length for smooth operation
6. Pro Tip from Manufacturer
If you cannot measure precisely, just provide:
Photos of the installed gas spring
Application (car model / cabinet / bed)
Approximate opening angle
A professional supplier can help you determine the correct size.
Conclusion
Correct length measurement ensures:
Proper fit
Smooth operation
Longer service life
If you’re unsure, it’s always better to confirm before ordering rather than replacing later.
Need Help?
We support:
OEM replacement matching
Custom gas spring sizing
Technical selection guidance
Feel free to reach out.
4️⃣How to Select Tube/Rod Diameter
Introduction
When selecting a gas spring, many people focus on force and length, but overlook another critical factor:
Tube and rod diameter
Choosing the wrong diameter can result in:
Poor stability
Reduced service life
Oil leakage or seal failure
Insufficient load capacity
In this guide, we’ll explain how to select the right tube and rod size for your application.
1. What Do Tube and Rod Diameter Affect?
Rod Diameter
The rod plays a key role in:
Stability during movement
Resistance to side loads
Service life of the gas spring
Tube Diameter
The tube determines:
Internal gas volume
Pressure capacity
Overall durability
In simple terms:
Rod = strength & stability
Tube = power & durability
2. Rod Diameter Selection Guide
Rod diameter is critical for avoiding bending and ensuring smooth operation.
Typical Ranges:
4–6 mm
game pedal, car refrigerator
Light equipment, electronic components
Micro stroke
6–8 mm
Light-duty applications
Small cabinets, lids
Short stroke
8–10 mm
Medium-duty applications
Automotive hood and trunk
Most common size
10–12 mm
Heavy-duty applications
Industrial equipment
High load or long stroke
Key Considerations:
- Load weight
- Installation angle
- Side force (very important)
- Frequency of use
Higher side load = need thicker rod
3. Tube Diameter Selection Guide
Tube diameter works together with rod size and force requirements.
Typical Ranges:
- 12–15 mm
- Light applications
- Micro force, mini stroke
15–18 mm
Light applications
Lower force range
18–22 mm
Standard automotive & furniture
Balanced performance
22–28 mm
Heavy-duty / industrial
High force requirements
Key Considerations:
- Required force (N)
- Stroke length
- Operating pressure
- Expected lifetime
Higher force = larger tube needed
4. Matching Tube & Rod Diameter (Important)
Tube and rod are not selected independently.
Typical combinations:
15/6 → Light duty
18/8 → Standard furniture
22/10 → Automotive
28/14 → Heavy industrial
A mismatch can cause:
Seal wear
Instability
Reduced lifespan
5. Common Mistakes
❌Choosing Based on Force Only
Ignoring diameter leads to early failure.
❌Undersized Rod
May bend under side load.
❌Oversized Design
Unnecessary cost increase.
❌Ignoring Usage Conditions
High-frequency or angled installations require stronger structures.
6. Application Differences
Automotive Gas Springs
Typically standardized sizes
Must match OEM specifications
Furniture Gas Springs
More flexibility
Cost-performance balance is key
Industrial Applications
Require heavy-duty design
Larger diameters for durability
7. Pro Tip from Manufacturer
If you are unsure, provide:
Load weight
Stroke length
Installation position
Usage frequency
A professional supplier can recommend the correct combination quickly.
Conclusion
Selecting the right tube and rod diameter ensures:
Stability
Safety
Longer service life
It’s not just about force — structure matters just as much.
Need Help?
We support:
Custom sizing
OEM matching
Technical consultation
Feel free to contact us.
5️⃣How to Choose End Fitting
Introduction
Choosing the correct end fittings and installation method is critical for safe, reliable, and long-lasting operation of gas springs.
Even with the correct force, length, and rod/tube diameter, improper fittings can cause:
Binding or jamming
Premature wear
Reduced service life
Potential failure
In this guide, we’ll explain how to select the right end fittings and mounting orientation.
1. Common Types of End Fittings
Gas springs come with various end fittings depending on application. The most common types include:
| Fitting Type | Description | Typical Application |
|---|---|---|
| Ball Joint | Provides pivoting movement | Automotive hoods, trunk lids |
| Eyelet | Circular loop for bolt connection | Furniture, light industrial |
| Clevis (Fork) | Fork-style connection | Industrial machinery, heavier loads |
| Bracket Mounting | Fixed bracket attachment | Cabinets, equipment panels |
2. Key Points When Choosing Fittings
1️⃣ Rod Down Orientation
Generally recommended for longer life
Ensures proper lubrication of internal seals
Minimizes leakage risk
2️⃣ Avoid Side Loads
Side loads reduce stability and cause premature wear
Ensure the load acts along the rod’s axis
3️⃣ Allow for Correct Pivot Angles
Each fitting has an ideal pivot range
Avoid over-rotation that causes bending or binding
4️⃣ Consider Application Requirements
Load weight
Stroke length
Frequency of use
Environmental conditions
3. Installation Best Practices
Always mount gas springs according to manufacturer guidelines
Ensure pivot points are properly aligned
Check for any interference or obstacles along the motion path
Regularly inspect mounting brackets and fittings for wear
Proper installation prevents:
Binding
Excessive wear
Potential operational failure
4. Pro Tip from Manufacturer
If you are unsure which fitting to choose:
Share photos of your current installation
Indicate load, stroke, and orientation
Include pivot angle or mounting constraints
A professional supplier can recommend the optimal fitting for safety and longevity.
Conclusion
End fittings are not just accessories — they are essential to safe and reliable gas spring operation.
Choosing the right type and orientation ensures:
Smooth pivoting
Reduced wear
Long service life
Even a perfectly sized gas spring can fail without proper fittings.
🔧 Need Help?
We provide:
Custom fitting recommendations
OEM / ODM mounting solutions
Technical consultation
👉 Feel free to contact us for guidance.
6️⃣Gas Spring Installation Guide
Introduction
A correctly installed gas spring is crucial for safety, smooth operation, and long service life.
Even if you have the right force, length, diameter, and fittings, improper installation can lead to:
Binding or jamming
Premature wear
Seal damage or leakage
Potential accidents
This guide covers step-by-step installation best practices.
1. Preparation Before Installation
1️⃣ Check the Gas Spring
Confirm force, length, rod/tube diameter, and fittings match your application
Inspect for any visible damage
Ensure rod is clean and lubricated if recommended by the manufacturer
2️⃣ Review Mounting Points
Ensure brackets or attachment points are strong enough for the expected load
Check alignment and pivot positions
Make sure there are no obstacles along the motion path
3️⃣ Orientation Matters
Rod down orientation is usually recommended
Keeps the seals lubricated
Reduces leakage risk
Avoid side loading
Ensure pivot angles allow full stroke without binding
2. Installation Steps
Step 1: Position the Gas Spring
Align the gas spring with the intended motion path
Confirm the rod can fully compress and extend without obstruction
Step 2: Attach End Fittings
Use the correct fittings (ball joint, eyelet, clevis, or bracket)
Ensure bolts, pins, or screws are tightened to manufacturer specifications
Verify pivot angles are within recommended range
Step 3: Secure Mounting Points
Double-check bracket and hinge strength
Ensure no wobble or misalignment
Step 4: Test the Operation
Slowly extend and compress the gas spring
Look for binding, unusual noises, or uneven movement
Adjust pivot points if necessary
3. Common Installation Mistakes
❌ Wrong orientation → premature wear and leakage
❌ Side loads → bending or instability
❌ Incorrect pivot angles → binding or limited stroke
❌ Loose fittings → failure under load
❌ Improperly rated spring → over-compression or excessive force
4. Automotive vs Furniture Applications
Automotive:
Often OEM replacement, precise fit is required
Installation instructions usually provided in manuals
Furniture:
More flexibility, but correct pivot angles and orientation still critical
Use adjustable brackets when possible
5. Maintenance Tips
Regularly inspect mounting points and fittings
Check for leaks or unusual movement
Replace worn or damaged springs immediately
6. Pro Tip from Manufacturer
If unsure about installation, provide photos or short videos to your supplier
Professional advice can prevent costly mistakes and extend service life
Conclusion
Proper gas spring installation ensures:
Smooth operation
Longer service life
Safety for users and equipment
Even the best-selected gas spring will fail if installed incorrectly. Follow these guidelines for reliable performance.
🔧 Need Help?
We support:
Installation guidance for OEM and custom applications
Technical consultation
Troubleshooting for existing installations
👉 Contact us for expert support.
Automotive Gas Struts
How to Choose Correct Gas Struts If I Have OE Number
The OE (Original Equipment) number for car lift supports is a unique manufacturer-specific part number, such as 4B9827552N (Audi/VW), 51 23 8 402 551 (BMW), or 7L1Z-7842105-A (Ford), stamped directly on the metal cylinder of the gas strut. Finding this number is crucial for finding an exact replacement.
Normally you can easily find it in your original struts of your car. With it, you can provide it to the sellers, they will find correct size and force
How to Choose Correct Gas Struts If I Don't Have OE Number
If your original gas struts are already replaced before, so sometimes you could not find correct OE number. To ensure you get correct size and type, you need provide two parameters
– Your car brand, car model and installation location (hood or trunk)
– EL, Stroke and Force (Force is not mandatory because it is not easy to get the value)
Model compatibility
Introduction
Automotive gas struts are essential for hoods, trunks, tailgates, and liftgates.
However, selecting the correct gas strut is not universal — every car model has specific dimensions, force, and fittings. Choosing the wrong strut can lead to:
Improper opening or closing
Safety hazards
Premature wear or failure
Customer dissatisfaction
This guide explains how to ensure model compatibility for automotive gas struts.
1. Why Model Compatibility Matters
Automotive gas struts vary by:
Length (extended and compressed)
Force / pressure
Tube and rod diameter
End fittings (ball joint, eyelet, clevis)
Mounting position and angle
Even a slight mismatch can cause binding, misalignment, or overloading.
2. Key Parameters for Model Matching
1️⃣ Extended Length
Distance between mounting points when fully extended
Must match the specific car model for proper hood/trunk operation
2️⃣ Compressed Length
Distance when the strut is fully compressed
Incorrect compressed length → strut may bottom out or not fully open
3️⃣ Force / Pressure
Lifts the hood or trunk with enough stability
Force too low → hood may close suddenly
Force too high → difficult to open
4️⃣ Rod & Tube Diameter
Impacts durability, stability, and load capacity
Larger diameter → higher load or longer stroke
5️⃣ End Fittings
Ball joint, eyelet, clevis, or bracket
Must match original mounting points
3. How to Check Model Compatibility
OEM Part Number Reference
Use the original part number from the vehicle manual
Compare dimensions and force ratings
Direct Measurement
Measure extended/compressed length, rod/tube diameter, and end fittings
Cross-check with supplier specifications
Database / Catalog
Use manufacturer or supplier compatibility tables
Check year, model, trim, and hood/trunk type
Supplier Consultation
Provide photos, measurements, and part numbers
Experienced suppliers can recommend the correct strut quickly
4. Common Mistakes
❌ Using “one-size-fits-all” struts
❌ Ignoring OEM force specifications
❌ Using incorrect end fittings
❌ Neglecting mounting angle or position
5. Best Practices for B2B Buyers
Maintain a compatibility database for your main brands/models
Verify force, length, and fitting before ordering
Always test on sample vehicles if possible
Communicate exact OEM part numbers with suppliers
6. Pro Tip from Manufacturer
We recommend creating a simple table for each vehicle model with:
Vehicle make & model
Year
OEM part number
Required length & force
End fitting type
This saves time, avoids errors, and builds professional credibility with clients.
Conclusion
Model compatibility is critical for automotive gas struts.
Even a high-quality strut will fail or cause safety issues if it does not match the vehicle model.
By checking length, force, diameter, and fittings, you ensure reliable operation and customer satisfaction.
🔧 Need Help?
We provide:
Automotive gas strut OEM & aftermarket compatibility
Custom recommendations for European, Asian, and other markets
Technical consultation and database support
👉 Contact us for professional guidance.
Furniture Gas Springs
Cabinet Gas Spring Selection
Bed Lift Mechanism
Soft Close vs Normal
Other Applications
Industrial:
– Enclosures
– Machine covers
– Toolboxes
– Mini/Micro
– Stainless
FAQ
Q: Can I replace a single gas spring only?
A: Yes, but ensure the replacement matches the force and size specifications of the paired spring.
Q: What happens if the force is too high?
A: It may damage the lid, hinge, or surrounding components and pose safety risks.
Q: How do I calculate force for a new application?
A: Measure load, pivot point, and angle. Use the formula: Required Force = Load × Geometry Factor × Safety Factor.
Q: Can I customize gas spring force or size?
A: Yes, DampFlex provides custom solutions based on your technical requirements.
Q: Common mistakes
A:
– Selecting force without considering EL and stroke
– Ignoring temperature effects
– Incorrect rod diameter for application load
– Using wrong end fittings or mounting orientation
– Replacing gas springs without recalculating specifications
Q: If provide assistance Selecting the Right Gas Spring
A: Yes, our engineering team is ready to help you select the ideal gas spring for your application. Provide your application details and we’ll guide you to the optimal solution.