Informational Guide

How To Measure Gas Struts

In this article, we show you how to measure gas struts on your car with a step by step guide.

Gas struts are designed to provide maximum damping force to your vehicle’s suspension. To ensure you have the right fit, it’s critical you know how to measure gas struts.

In this article, we will cover how to measure and install gas struts, ensuring you get the right application for your vehicle.  

Gas struts can be used for numerous parts of the car, although they are most known for providing suspension support

Whether they are part of the suspension or holding up the open trunk lid, gas struts look like a cylinder. Inside the cylinder, there is compressed gas and a piston that generates force. With this piston, less force is needed to provide the damping power.  

However, gas struts can lose pressure over time, making them less efficient and generally louder.

faulty gas struts

You can have a professional re-gas the struts, but it’s often better to learn how to measure replacement gas struts for better support.  

What To Look For When Measuring Gas Struts (Sizing Guide) 

Before you replace the struts, you need to know what size they are. After all, you can’t put new struts on a vehicle that don’t fit. While you can opt for a standard size, there’s a good chance it won’t fit your application. Here are a few things to consider when learning how to measure gas strut size. 

Size Of Gas Strut When Extended 

You will want to know how to measure gas strut length when it is extended and compressed. Both of these figures will be important in replacing the struts.  

Diameter Of Strut (Shaft & Cylinder) 

You must measure the entire diameter of the strut, including the shaft and cylinder. Both of these measurements will be important if you want the right replacement.  

Newton’s Force Noted On The Struts 

You can find the Newton’s number on the struts measured by Nm. You may also find it by checking the manufacturer’s website. 

gas strut shaft

It’s important that your replacement struts have the same Nm rating to hold the weight properly.  

How To Measure Gas Struts (Step-By-Step Guide) 

If you can’t get an exact match of your gas strut by searching the part number, you want to measure it for a quality replacement. Follow these steps to find the struts that work for your vehicle. 

  1. 1
    Measure the extended length of the gas strut. You start the measurement at the middle of the end fitting and go to the middle of the other end fitting. You can also take a measurement of the compressed strut for reference.  
  2. 2
    Your next step is to measure the diameter. You do this across the rod and shaft, as well as the canister.  
  3. 3
    Look for the Newton's Meter rating. It is listed as Nm on the shock, or you can find the information on the manufacturer's website.  
  4. 4
    You will also need to make a note of the end fittings to ensure they will work with your vehicle.  

If you are struggling to figure out how to find the right strut, you might consider using a gas strut measurement calculator. You may also seek help from a professional mechanic if you aren’t sure what to replace your gas struts with. With the wrong struts in place, the suspension of your vehicle could be compromised, leading to dangerous on-road handling.

Things To Remember When Replacing Gas Struts (Installation Tips) 

  • Gas Struts Correct Pressure  
    It’s important to double-check the pressure in the gas strut to ensure it works as it should. Compress the strut and allow it to extend to ensure it works as intended.  
  • Gas Struts Strength  
    If the strut appears to bounce back too quickly, it might have been filled with an excess of pressurized gas. It’s best to avoid any strut that seems dangerous.  
  • Piston Protection  
    The strut must be installed in the same place as the old one. For this reason, you want to ensure that the placement of the piston is protected from debris and corrosion.  
  • Safety Measures  
    The car’s suspension is nothing to mess around with. If you aren’t sure how to install the struts safely, it’s best to have a professional handle the installation for you.  
person fixing a car

People Also Ask (FAQs)

How much do gas struts cost? 

A pair of new struts will cost between $450 and $900 for the parts and labor. However, some vehicles are going to cost more simply because the parts are more expensive or they are harder to install.  

How long do gas struts last? 

Gas struts should last at least five years in normal conditions. However, driving in extreme temperatures, pushing your vehicle to the limits or carrying heavy loads can cause the struts to wear out prematurely.  

How do you release gas struts? 

The gas strut has an intense amount of internal pressure. You use an Allen key to undo the grub screw until you hear the gas escape. You only want to release enough gas to last about a second at a time, or you could let too much out.  

Are gas struts constant force? 

Gas struts have a constant force of pressure through the entire stroke. This is one way they are different from the leaf or composite suspension and also why they should always be treated with caution.  

Are gas struts adjustable? 

Some gas struts can be adjusted for a better ride. Check the strut owner’s manual to adjust the suspension appropriately or visit with your local certified mechanic for more support.  


Learning how to measure gas struts doesn’t require special skills. With a little mechanical know-how and some basic skills, you can make sure you have the right struts for your vehicle.