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What Angle Do You Install Gas Struts?

Published by: Nathan
Date of Publish:

A vehicle uses several components to function correctly and ensure safety and comfort to the driver and passengers. Some parts were there from the beginning, while others were developed over time to make riding a car a pleasurable experience. Doors in a car, as well as indoors in houses and offices, use a strut to make closing an automatic function. A gas strut is a type of spring where instead of elastic coils, there is compressed gas to absorb the shock. The gas is kept in a cylinder, and it is sealed with a sliding piston capable of moving to withstand the external force applied parallel to the direction of the piston shaft.

Read on to learn more about gas strut mounting positions and the components that usually come with them. After reading this article, you will better understand the working and applications of this kind of spring. For more detailed info, please refer to what does a gas strut do

Gas Strut’s Mount Position- Explained

There are a few kinds of gas strut mount positions that you can try for your vehicle. For the gas strut, there are two main mounting points – the fixed and the moving mounting points. The moving mounting point can rotate through as an arc while the fixed point has a fixed position. Read on to know more about the different kinds of mount orientations you can follow.

Mount Orientations

1.       Push-Up Design

This kind of mounting can be identified easily as the end at the lowest point remains at the lowest point, irrespective of whether it is open or closed. The moving point is closer to the hinge, as compared to the distance between the fixed mounting point and the hinge.

The rod orientation is an important thing to consider as it affects efficiency. Unless the rod is lubricated, the strut demands the rod mounted downwards so as to achieve the main seal’s proper lubrication. The only drawback the push-up mounting orientation has is that it requires additional strength when it is to be lifted. This is because there is an increase in the cantilever of the lid from the support provided by the strut.

The damping effect offered by this mounting orientation is one of its most significant advantages. It provides a consistent damping effect at the end of the stroke. The oil always remains at the bottom of the tube, so the damping effect occurs at the same point in the lift cycle.

2.       Flip-over Design

You can easily recognize this strut from its design and structure. When closed, the end of the strut stays at the lowest point but rotates to the highest point when it is open. Also, the distance of the moving mounting point from the hinge is more than the hinge when compared to the distance between the hinge and the fixed mounting point.

If you are not using any lubricant for the rod, then it is advisable to mount the rod down so that there is proper lubrication of the primary seal in the closed position.

The biggest drawback this kind of mounting has is that it lacks proper damping control throughout the stroke. When a stroke starts, the oil is at the bottom of the primary seal, and after passing the horizontal position, it starts to run down the tube toward the end of the tube. The piston moves up through the tube and after meeting the oil, it will slow down until the oil has passed. The extension speed also drastically increases until the stroke ends, with no dampening. The flip-over design's main advantage is that it places less strain on the hinges than the push-up design.

More About Gas Strut Mounting

Besides mounting, other factors must also be considered for a gas strut. Let us take a look at those factors, as it will help you understand the component better.


The crossover point is one where the strut takes over the lifting action. To be more accurate, the specific position of the strut causes gravity to work on lifting the piston. This is not a fixed value and can differ from model to model. Usually, it is around 10° to 30° from the fully closed position of the strut. However, several internal as well as external factors like the internal components’ friction of the spring, end connectors, and hinges will change the location and degree of the crossover position by several degrees between opening and closing.

Self-rise & Self-close

Both of these are essential angles that determine a position or angle where there are minor changes in how the strut lid works. Self-rise refers to an angle where the lid can be lifted without any manual intervention or assistance. On the other hand, the self-close angle is where the lid closes without any intervention from the user.

During the strut operation, it’s inadvisable to have the lid opened up without the operator's input. This process is undesirable and unpredictable as it opens the lid without warning. It happens whenever the force increases above nominal due to reasons like elevated ambient temperatures and such.

How Different Temperature Affects Handling

The temperature plays a vital role in determining the output force and the handling force. There are significant changes that occur at different specific temperatures. Check out how handling is affected in two particular cases - 20°C and also at 65°C.

20 Degrees Celsius

If you look at the graph representing the effect of temperature on handling, you can crossover at 20OC. here, a crossover occurs at an opening angle of around 7°, and the handling forces are acceptable in both opening and closing.

65 Degrees Celsius

At 65°C, you can observe a lift occurring almost instantaneously. This is an unpredictable and hence undesirable behavior since it happens without any input from the user or operator. This may often turn out to be dangerous because of its unpredictability.

Talking About Dampers

A damper is one of the most important devices used to adjust and regulate the airflow in a strut. Besides, it can also regulate other physical characteristics to keep the system functioning at an optimal and efficient rate. Read on to learn more about the different types of dampers and their specific characteristics.

Extension Dampers

This kind of damper needs to be mounted in a rod-down position. This arrangement allows them to offer proper damping all around the entire stroke. If they are mounted in the opposite kind of arrangement or rod-up, then there will be negligible or no damping effect at all.

Compression Dampers

This kind of damper needs to be mounted rod-up to ensure the system receives a consistent damping effect throughout its operation. If they were to be mounted rod-down, then the dampers will offer negligible or no damping effect at all.

There is no issue regarding the lubrication of the primary seal since the high volume of oil used in the dampers offers natural lubrication.

Practical Applications

Check out a few practical applications of a gas strut.

Unused Stroke

If you want to keep unused strokes, there are a few ways to do the same. This will help the system stack up on manufacturing tolerances. As a result, this prevents “bottoming out” before the lid is fully closed. 

Preventing Instant Lift

Instant lift is undesirable in which the lid opens without the operator’s intervention. If you can position the moving mounting point in such a position that it creates an over-center condition when the lid is closed, the chances of instant lift are reduced.

Reducing Handling Forces

There are many ways to reduce the handling forces in your system. You can move the mounting point closer to the pivot or the fixed point to a more suitable location. On the other hand, you can also consider reducing the opening angle. These methods would help you reduce the handling forces by quite an amount.

Measuring Gas Strut Length

If the gas strut that came with a particular machine or system gets damaged, it is necessary to get a spare strut with the exact measurements. Unless you get a gas strut with the exact length measurement, compatibility issues may arise, and the repair job will be held up. Follow the steps given below to measure your gas strut accurately.

  1. Match the length measurements with those from the catalog to find the most suitable one.
  2. Measuring the length of a gas strut is quite easy, and there is significantly less chance that something would go wrong. Most spare gas struts are adjustable, so if you do not find a model with the exact measurements, you may choose something closer. You may also contact the manufacturer or supplier if you cannot find a spare strut of the exact measurements as the original.

Gas Strut Installation Guide

Several steps must be followed while installing a gas strut to your vehicle or a door. Unless you follow the fixed rules and steps, there are chances of undesirable damages or improper system functioning. Check out the steps to follow for installing a gas strut.

  1. Prop the door to an open position. For most hinged doors, the open position is at a right angle to the closed position.
  2. Follow the length measurements mentioned on the strut chart. This measurement gives the distance between the rotation point of the hinge and the top mounting point of the gas strut.
  3. Mount the gas strut as mentioned in the manual guide you got with it. It is important to mount the strut with the bigger tube at the top.
  4. After mounting the gas strut, it is safe to remove any prop holding your door open. The struts can manage the weight of your door by themselves.

Unless you have prior experience working with gas struts, it is not a good idea to try installing them yourself. You may try it out for smaller doors, but it is better to leave the more significant tasks to professionals. For amateurs and first-timers, there is always a chance of messing up the measurements, which can be quite a disaster.


Now you know more about gas struts and should be able to work on installing them for your vehicle or any other machinery. The proper knowledge of this component will help you understand whenever there are issues with it, and you can take the necessary steps. However, it is always advisable to get your struts and mechanical systems checked by a professional mechanic to avoid unwanted damage.

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