industrial-springs.com 
Springs for Automatic Opening of the Hatch
Do you want the hatch to open automatically?
These springs make it possible. Simply mount them onto the gas springs on hatch. This enables automatic opening of the hatch. However, it may be difficult to find the spring / springs that fit. Please read the guide below before choosing a spring.
The Most Sold Models for Automatic Hatch
We recommend mounting a spring on both gas springs on the hatch to avoid distortion of the structure. It is impossible to categorise the correct springs for all car models but the most common ones are the following two models.
Long version
Model number: ST51740
This is our most commonly sold long version. The picture is an example. The material is thinner than the short version but it has a longer suspension. The model is available in stronger versions.
Dimensions
External diameter:
19,05 mm
Internal diameter:
9,52 mm
Length:
114,30 mm
Max.loaded length:
60,58 mm
Force at max. laoded length:
602N (ca. 60kg)
Order 2pcs here:
Short version
Model number: ST51150
This is the short version. The picture is an example. The material is relatively thick and the length is shorter. That creates a short, powerful suspension. The spring should fit onto most gas springs used for hatches.
Dimensions
External diameter:
15,88 mm
Internal diameter:
8,72 mm
Length:
50,80 mm
Max. loaded length:
33,02 mm
Force at max. loaded length:
461N (ca. 46kg)
Order 2pcs here:
How to Find the Right Spring
Different car models have different types of gas springs mounted to the hatch. The best way to find the right hatch is to take the following measurements:
- Suspension
When the hatch is shut, measure the visible part of the piston rod on the hatches. The visible length should equal slightly less than the maximal loaded length of the spring. It is important that there’s enough room for the spring to suspend under maximal load. If the hatch is loaded more than recommended, you risk causing damage to it. On the other hand, the load mustn’t be too weak as that may cause too little force to open the match automatically. - Piston Rod
The diameter of the spring must be large enough to fit over the piston rod. A small gap between the spring and the piston rod is recommended – approximately 1-2 mm. That gives the spring room to expand when it is loaded. In our assortment, we specify the maximum width of the piston rod over which each spring can fit. This is specified as (Dd) – Maximum Axle (mm). In most cars, an 8 mm piston rod is used for the hatch. - Force
The necessary force of the spring depends on the weight of the hatch. Unfortunately, there is no easy way to measure the force. - Temperature
The temperature impacts the force of the gas springs of the hatch. This affects the necessary force of the spring. Gas springs usually provide greater force at warmer temperatures and lower force at colder temperatures. Normally, gas springs are adapted to a temperature of approximately 20 degrees Celsius / 68 Fahrenheit. For every 10 degrees Celsius / 18 Fahrenheit change from this basis, the force of the gas springs will vary by approximately 3 %. Bear this in mind when selecting a spring. Consider using a stronger gas spring. See our selection here - Mounting
Be careful when removing the gas springs. The hatch may be heavier than expected and removal is best done by more than one person. After mounting the spring and gas spring, it is recommended to be aware when closing the hatch for the first time. If the spring is too forceful, it may damage the car.
Sodemann Industrial Springs cannot be held responsible for damage caused by purchased products. This also includes customers who receive help / guidance from Sodemann Sodemann Industrial Springs.