Adjusting Gas Struts: Optimally Matching Opening Angle and Force for Cabinet Flaps

January 17, 2026

Adjusting a gas strut on furniture flaps is not done via an adjustment screw on the stay itself, but through the exact positioning of the mounting points on the carcass and matching the extension force in Newtons to the weight of the front.

A precisely adjusted flap fitting ensures that the cabinet door opens smoothly upwards, stays securely in its end position, and does not slam shut uncontrollably when closing. Balancing flap weight and spring force is much like balancing a seesaw: if the lever arm or counterweight is incorrect, the mechanism will swing uncontrollably.

For joiners and fitters, the correct installation and alignment of gas struts is essential. This guide walks you through the technical parameters, force calculation, and step-by-step fitting adjustments.

Technical Foundations: Force, Stroke, and Angle

Before picking up any tools, the physical characteristics of the fitted components must be understood. A gas strut operates using compressed nitrogen that pushes a piston outwards.

Two values are crucial here:

The extension force, measured in Newtons (N). Typical values for furniture flaps range between 50 N and 150 N.
The stroke, which is the maximum travel distance of the piston rod in mm.

The opening angle of the flap (typically 75°, 90°, or 110°) is defined exclusively by the distance between the mounting plates and the pivot point (the hinge). Anyone wishing to alter the angle or adjust the leverage must reposition the screw-fixing points.

Difficulty and Time Required

Target group: Experienced DIYers, fitters
Time required: approx. 20 - 30 minutes per flap
Difficulty: Medium (requires precise measurement)

Required Tools and Materials

For fitting and adjusting flap fittings, the following tools are required:

Cordless screwdriver or manual screwdriver (drive PZ or PH, depending on the chipboard screws used)
Tape measure or accurate folding rule (reading in mm)
Bradawl or a 3 mm wood drill bit
Pencil and try square
Suitable gas struts in the correct strength

Step-by-Step Guide: Adjusting and Fitting Gas Struts

The following guide assumes that the flap is already attached to the carcass with hinges and that the struts are now being retrofitted or corrected.

Step 1: Determine the Correct Newton Rating

A common misconception is that an overly strong strut can be made "softer" via a screw. This is technically impossible. The force must be calculated beforehand. As a rule of thumb: 10 N corresponds to a load capacity of approximately 1 kg.

For example, if an MDF front weighs 4 kg, a total force of 40 N is required. Because wide flaps (from approx. 600 mm in width) must always be fitted with two struts to prevent the front from warping, you would choose two struts rated at 50 N each in this scenario (including a margin for lever travel). For solid timber fronts or larger dimensions, dedicated gas struts for heavy flaps with ratings from 100 N to 150 N per side must be selected.

Step 2: Basic Adjustment of the Flap Hinges

The gas strut is merely the supporting component. The actual guiding is handled by the concealed cup hinges on the top panel. Before clipping in the struts, the flap's reveal gaps must be aligned correctly. Adjust the hinges via the adjustment screws for height, depth, and side overlay. Check whether it is an overlay door (the flap sits fully on the carcass side panels) or an inset door, as this shifts the installation dimensions of the strut mounting brackets by the material thickness (typically 16 mm or 18 mm).

Step 3: Mark the Mounting Points for the Desired Angle

The opening angle is determined by the position of the round mounting plates. Manufacturers provide dimension charts for this based on stroke length (e.g. overall length 270 mm).

Example for a 90° opening angle with standard struts:

Fixing to the carcass (side panel): Measure exactly 250 mm downwards from the internal edge of the top panel. Measure approx. 25 mm inwards from the front edge of the carcass (depending on panel thickness). Mark the point.
Fixing to the flap: Measure approx. 90 mm from the hinge edge of the flap towards the centre.

If an angle of 110° is desired, the mounting points move closer to the pivot point (the hinge). However, this reduces the mechanical advantage, meaning the strut must exert more force to hold the flap open.

Step 4: Screw the Mounting Plates in Place

Pilot the marked points using the bradawl. Screw the mounting plates securely using suitable chipboard screws (usually 3.5 x 15 mm). Take care not to overtighten the screws, especially in melamine-faced chipboard. When working with System 32 line boring, Euro screws can often be used in existing 5 mm holes, provided the spacings match the manufacturer chart.

Step 5: Clip the Strut into Place and Check Alignment

Now press the ball joints of the gas strut onto the mounting plates until they click audibly into place. Important technical rule: In the closed position, the thick cylinder of the strut must point upwards (towards the carcass), and the thin piston rod downwards (towards the flap). Only then is the internal seal continuously lubricated by the enclosed oil, ensuring the end-position damping functions correctly.

Test the movement. The flap should open automatically from an angle of approx. 30° and remain in its open end position.

Common Installation and Adjustment Mistakes

Even with careful working methods, specific problems often arise that can be resolved with minor corrections.

Flap hits the stop hard when opening: The chosen force in Newtons is too high for the weight of the front. Alternatively, the mounting point on the flap is set too far from the hinge.
Flap does not stay open: The struts are undersized. On very light fronts, an incorrect angle may also be responsible. Move the mounting plate on the carcass a few millimetres downwards to improve leverage.
Front is warping: Only one strut was fitted to one side. For front widths of 600 mm or more, or with heavy materials, two struts (left and right) must strictly be installed.
Confusing the components: A gas strut actively pushes open. It must not be confused with a soft-close door damper, which merely slows down the closing motion.

Aesthetic Integration into Furniture

Technical function comes first, but the visual appearance inside the cabinet also matters. Depending on the carcass finish, fittings can be colour-coordinated. In dark cabinets, black gas struts look discreet and modern. For white kitchen wall units, white gas struts are suitable, while classic timber decors are often paired with neutral silver gas struts.

If the carcass geometry does not permit the use of gas struts at all (e.g. with very shallow carcass depths), purely mechanical flap stays must be used instead, where the braking effect is finely adjusted via a hex key screw.

FAQ: Frequently Asked Questions on Strut Adjustment

Can I reduce the pressure of a gas strut after purchase? No. The gas is sealed under high pressure inside the cylinder. There are no valves or adjustment screws to lower the pressure from, for example, 100 N to 80 N. If the strength is incorrect, the component must be replaced.

Why can I not compress the new gas strut by hand? This is normal. A strut rated at 100 N requires a force of approx. 10 kg to compress. Due to the smooth surface of the piston rod, it is virtually impossible to generate this force by hand alone. The mechanism only operates once fitted, aided by the mechanical leverage of the flap.

How do I release a fitted strut from the mounting bracket? The ball joints are secured with a small metal spring clip. Slide a flat-head screwdriver under this clip and lift it slightly. The strut can then be pulled off the ball head without force.

What alternatives are available for downward-opening flaps? Gas struts for upward-opening cabinet doors push open actively. For downward-opening flaps (e.g. on a bureau or drinks cabinet), specialised drop-down flap stays are required to cushion the downward pull and hold the flap horizontal.