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Gas Spring Calculator

Calculate the right gas spring for your flap, lid or trailer ramp. Enter dimensions and weight – you will get the recommended force, length and mounting points including an interactive sketch.

Please note: the gas spring calculator is a selection aid and does not replace an on-site technical check. No liability is accepted for the correctness of the results or for errors.

1 How does your flap open?

Ramp folds down e.g. horse trailer tailgate, loading ramp – the gas spring assists lifting Flap opens from bottom to top vertical flap, hinged at the top – e.g. tailgate, vent flap, serving hatch Lid opens upwards horizontal lid swings up – e.g. storage box, chest, engine hood

2 Describe your flap

Dimensions

Length (hinge to handle edge, mm) Width (mm) Thickness (mm)

Weight

Material (for the weight calculation)

Calculated from dimensions & material

≈ – kg

Weight of the flap (kg)

Angles & operation

Closed angle (°, 0 = horizontal) Opening angle (°) Number of gas springs Desired operating force

Mounting points

Use existing points Replacement spring – mountings already installed Suggest automatically New installation – we find the best points

You only need three measurements: the eye-to-eye dimension of your installed spring plus dimensions B and C on the fixed frame (each from the centre of the hinge). We calculate dimension A from those. You can take all measurements comfortably with the ramp/flap closed:

⭐ Eye-to-eye dimension (mm, measured with the ramp closed – the installed spring is fully extended there. This is the order length!)

Dimension A hinge → mounting on the flap (mm, along the flap) – calculated from the eye-to-eye dimension, no input needed Dimension B frame mounting: horizontal distance to the hinge (mm, towards the flap = positive) Dimension C frame mounting: vertical distance to the hinge (mm, downwards = positive)

💡 The gas spring runs diagonally between the two points. Its length is the direct eye-to-eye distance – usually larger than dimension A. Most reliable: measure this dimension directly on the installed spring – it is also the order length of the replacement spring.

Expert settings (centre of gravity)

Centre of gravity distance from hinge (mm, default = half the length)

All changes are calculated instantly – see the result below.

3 Sketch & simulation

Move flap: 80°

Detail: mounting points at the hinge

Enlarged view – dimensions B, C and D stay readable here even when they sit close together in the overall drawing.

A – on the flap B – frame, horizontal C – frame, vertical Eye-to-eye – order length

Force curve over the opening angle (marker = current slider position)

Flap moment (Nm) Gas spring moment (Nm) Hand force (N)

4 Result & recommendation

Recommended gas spring

–

Extension force F1 (per spring)

–

Total length extended (approx.)

–

Required stroke (min.)

–

Mounting dimensions (measured from hinge centre)

Dimension A – mounting point on the flap	–
Dimension B – frame mounting point, horizontal	–
Dimension C – frame mounting point, vertical	–
Distance between mounting points (flap open)	–
Distance between mounting points (flap closed)	–

The calculation is a non-binding recommendation based on your input (incl. 10 % safety margin) and is merely a selection aid. No guarantee is given for the correctness of the calculation or for freedom from errors; liability is excluded.