Should a Gas Spring Be Mounted Rod Down?
The short answer: yes — the preferred orientation is always rod down. The long answer is about what happens inside the gas spring, and it explains why mounting orientation has such a strong effect on service life and comfort.
Why rod down?
Along with the nitrogen, the body contains a small amount of oil. This oil has two jobs: keeping the seal permanently wet, and providing hydraulic cushioning (end damping) at the end of the stroke. With the rod pointing down, gravity holds the oil exactly where it belongs: on the seal and in the piston exit zone. The result: the seal runs lubricated and lasts longer, and the lid comes to a soft stop at the end of opening.
Mounted rod up, the oil drains to the bottom of the tube — the point furthest from the seal. The seal runs dry (early leakage) and the end damping disappears (the lid hits the end of travel with a "clack").
Horizontal and angled mounting
In most lid applications the gas spring is not perfectly vertical — that is not a problem. The rule is: with the lid closed, the rod end should sit as low as possible. The closed position is where the gas spring spends most of its time, and that is where the oil should collect at the seal. For applications that must operate fully horizontal, say so when ordering — the oil volume and seal arrangement are adjusted accordingly.
Exceptions and special cases
- Dampers: Dampers with delayed damping (idle stroke) are position-dependent and must be mounted rod down; rod-up or horizontal mounting lengthens the idle stroke. Position-independent dampers can also be produced — describe your application.
- Locking (PTL) types: The orientation rule is the same; in addition, access to the actuation (button/cable) may dictate the orientation. If the orientation of a locking unit needs to change, consult us first.
- Traction types: Although the working principle is reversed, the oil-seal relationship is the same; the unit is configured for its orientation in production.
· Keep the mounting points axially aligned — misalignment is the seal's number one enemy; if in doubt, choose a ball-stud.
· Never let the gas spring be used as a carrying handle, a step or a support.
· Keep paint, adhesive and labels off the rod surface.
Get the mounting orientation and end fittings right from the start, and the gas spring will run quietly for years. Use the configurator to find the right end fitting and size group for your application.
Open the Configurator →