Fitting Full-Extension Drawer Runners — Step by Step

July 4, 2026

A full-extension drawer runner is a sliding mechanism that extends 100 percent out of the cabinet carcass, allowing complete access to the entire contents of the drawer.

Fitting drawer runners correctly demands precise measurements and a fundamental technical understanding. Installation requires clockwork precision — a discrepancy of just a few millimetres when positioning the runners will inevitably cause the drawer to stick or result in uneven gaps across the furniture front. This guide is aimed at fitters and experienced tradespeople, providing detailed instructions for installing side-mounted ball bearing runners.

Preparation: Choosing the Right Runners

Before picking up a screwdriver, the exact specification of the fittings must be determined. Full-extension drawer runners come in various lengths, weight capacities, and kinematic designs.

Length: The nominal length of the runner depends on the depth of the drawer box. Common dimensions for standard furniture range between 250 mm and 600 mm. Compact bathroom furniture often uses drawer runners 250 mm, whilst kitchens or workshops frequently utilise lengths of 500 mm or 600 mm. The runner must never be longer than the internal cabinet depth minus the rear panel.
Load capacity: Standard runners are rated for 30 kg to 45 kg. For tool cabinets or deep pantry pull-outs, heavy-duty drawer runners must be used. Depending on the model, these handle 80 kg, 100 kg, or more, and are frequently available in extended lengths (e.g., 900 mm or 1200 mm).
Convenience features: A strict distinction must be made between two contrasting mechanisms. Drawer runners with soft-close cushion the closing momentum and gently pull the drawer into its final seated position. In contrast, push-to-open drawer runners (tip-on) are designed for handleless fronts, where pressing the front panel causes the drawer to pop open. These two systems cannot be technically combined within the same runner.
Runner type: Whilst simple roller runner drawer slides are typically designed as single-extension (partial-extension) systems, full-extension runners are generally based on telescopic ball bearing runners (side-mounted) or concealed under-drawer runners (mounted beneath the drawer base).

Required Tools and Materials

The following materials and tools are required to fit side-mounted ball bearing runners:

Cordless drill/driver or manual screwdriver
Matching bits: PZ (Pozidriv) size 2 or TX (Torx) size 15/20 – depending on the chosen screw
Chipboard screws: Countersunk, Ø 3.5 mm or 4.0 mm, typically 16 mm in length (depending on the material thickness of the drawer side)
Alternatively, for pre-drilled cabinets: Euro screws (Ø 6.3 mm) for 5 mm diameter holes
Tape measure or folding rule
Pencil and try square
Optional: Marking jig for the System 32 grid

Fitting Full-Extension Runners — Step by Step

Installation tolerances for side-mounted ball bearing runners are minimal. The internal cabinet width must equal the exact outer width of the drawer box plus the combined installation clearance of both runners. A standard ball bearing runner requires an installation space of exactly 12.7 mm per side (25.4 mm in total).

Step 1: Separate the Runner Profiles

A side-mounted telescopic full-extension runner consists of an outer carcass profile and an inner drawer profile. These must be separated for fitting.

Extend the runner fully.
Inside the telescopic mechanism, a small plastic release lever becomes visible.
Press this lever up or down (depending on the model) and pull the inner drawer profile completely out of the carcass profile.

Step 2: Mark and Mount the Carcass Profile

The wider profile is secured to the inner side of the furniture carcass.

Determine the height: Mark the desired installation height of the drawer. It is advisable to mark the line for the lower row of screws.
Depth positioning: The profile is not fitted flush with the front edge of the carcass. For overlay fronts, the profile is usually set back by 2 mm. For inset fronts, the thickness of the front panel (e.g., 19 mm) plus a 2 mm gap must be added to the setback.
Securing: Align the carcass profile perfectly level horizontally. Use the horizontal slotted holes for the initial screws, allowing for later depth adjustments. If the carcass features a System 32 hole pattern, secure the profile into the 5 mm drill holes using Euro screws. Insert at least three screws (front, centre, rear) per profile.

Step 3: Mount the Drawer Profile

The narrow, separated profile is now screwed onto the exterior sides of the drawer box.

Place the drawer onto the workbench in front of you.
Position the drawer profile along the bottom edge of the drawer side. The front of the profile must sit perfectly flush with the inner face of the drawer front (or the front edge of the drawer side).
Use the vertical slotted holes for the initial screws (Ø 3.5 x 16 mm). This allows for fine height adjustment of the front panel later on.
Ensure that the profiles on both sides of the drawer are mounted at the exact same height.

Step 4: The Marriage (Inserting the Drawer)

Now, the carcass and drawer are brought together.

Pull the ball cages of the fitted carcass profiles fully forward to the front edge of the carcass.
Hold the drawer level and guide the drawer profiles into the carcass profiles.
Push the drawer backwards applying smooth, steady pressure.
At roughly two-thirds of the travel, you will feel resistance. Continue pushing until a distinct "click" is heard. The release levers are now re-engaged.

Step 5: Functional Check and Fine Adjustment

Check the operation of the drawer. It must glide smoothly without juddering and close flush.

Check gap alignment: If the gaps around the front panel are uneven, pull the drawer out. Slightly loosen the screws in the vertical slotted holes of the drawer profile, adjust the height (1 mm to 2 mm is often sufficient), and retighten the screws.
Final fixing: Once the position is perfect, drive two to three additional screws into the round fixing holes on both sides. This permanently locks the position, preventing it from shifting under load.

Common Installation Mistakes

Even experienced tradespeople occasionally make errors when installing drawer systems. Pay particular attention to the following points:

Carcass is out of square: If the internal width at the back of the carcass deviates by more than 1 mm from the front internal width, the full-extension runner will bind. The ball cages will run stiffly or suffer permanent damage. Measure the diagonal dimensions of the carcass to verify squareness.
Protruding screw heads: Using pan-head screws instead of countersunk screws, or countersunk heads that are too large (e.g., Ø 5 mm instead of 3.5 mm), causes the inner runner profiles to scrape against the screw heads during extension.
Ball cage slid backwards: If the ball cage sits at the rear of the carcass profile when the drawer is inserted, the profiles can jam and push the steel balls out of the cage. Always pull the cages fully forward before insertion.
Soft-close mechanism does not engage: This frequently happens if the carcass profile is mounted too far back. The activator pin on the drawer then fails to reach the damper mechanism inside the carcass profile. Check the setback dimension (typically 2 mm).

FAQ – Frequently Asked Questions

Can I replace a single-extension runner with a full-extension runner? Yes, this is generally possible provided the side clearance (installation width) is identical. For side-mounted ball bearing runners, this is usually 12.7 mm. However, existing drill holes can rarely be reused, as hole patterns vary between manufacturers.

How do I determine the correct length for my drawer runner? Measure the outer length of the drawer box (excluding the attached front panel). For example, if it measures 490 mm, choose a runner with a nominal length of 500 mm, provided the carcass is deep enough. The runner should support the drawer box without colliding with the rear wall of the carcass.

What does System 32 mean in furniture fittings? System 32 is an international standard in furniture manufacturing. It refers to rows of holes in cabinet sides spaced at continuous 32 mm intervals, with hole diameters of 5 mm. The distance from the front edge of the cabinet to the first row of holes is standardised at 37 mm. High-grade full-extension runners feature hole patterns aligned precisely with this grid, eliminating the need for manual marking out.

How much weight can a full-extension runner hold? This depends on the specification. Standard ball bearing runners carry between 30 kg and 45 kg (including the dead weight of the drawer). Heavy-duty runners should be selected for large pots or tools. A heavy kitchen cabinet pull-out 60 cm for substantial food storage often requires runners rated at 60 kg or more.