Other calculation for gas spring

Decision support

1 - Gas spring pressure/force

The pressure required for the gas spring is calculated by substituting the values ??used in the following formula:

F1 = ((m x RH)/(2 x N x x2) + 5) x 9.81 = gas spring pressure expressed in Newtons 

  • F1 = gas spring pressure/force
  • N = number of gas springs desired
  • m = weight (kg) of the tailgate/object to be lifted, manoeuvred
  • RH = length (in metres) of the tailgate object to be lifted, manoeuvred
  • x2 = distance (in metres) between the point of application of the gas spring on the tailgate and the rotation axis of the tailgate.

The number 5 represents a constant force of 5 kg/p, equivalent to rubbing actions.


For a hatchback with the following characteristics and values:

  • N = 2
  • m = 50 kg
  • RH = 1,50 m
  • x2 = 0.40 m

F1 = ((50 x 1.5) / (2 × 2 × 0.40) + 5) = 9.81 x 508N

In this case, since the tolerance is +/- 50 N, we would recommend two 550N gas springs.

2 - Determine the dimensions of the gas spring.

Generally we recommend that you use the following ratio: stroke = 1/3 of RH per 90° (opening

Example: RH = 1.5m         1.5 / 3 = 0.5m


  • Stoke 500mm = ST 500+...+V...
  • Choose the rod diameter depending on the type and frequency of use. Ditto for the end fitting type (welded or threaded hinge eye). 
  • The X2 slope should be 50mm less than the gas spring stroke (fig 2 and fig 4).
  • The Y1 slope should be 100mm less than the gas spring stroke (fig 1 and fig 3).

Note: The installations noted above are examples only and do not in any way incur the liability of Berthold Marx.

3 - Once you have this information, you can find the right gas spring references by consulting our catalogue.

4 - Important Recommendations

  • Always install the gas spring vertically with the rod facing down.
  • Attachment points must be in line. They must allow for a certain clearance so that the rod is not subjected to lateral stress.
  • Avoid any impact on the gas spring.
  • Never disassemble a gas spring:
  • Do not allow any paint whatsoever on the piston/rod as this could result in a gas leak.

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EMail : info@bertholdmarx.com

Berthold Marx

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