Full-Extension Runners H45: Installation Dimensions, Load Capacity and Cabinet Depth at a Glance

A full-extension runner with an installation height of 45 mm allows a drawer to be extended fully to 100% and offers high stability for medium to heavy loads thanks to its side-mounted ball bearing guide.

For professional furniture making and demanding installation work, choosing the correct drawer runner is essential. The designation H45 refers to the exact installation height of the runner of 45 mm. This type is the industry standard for side-mounted runners and is used in kitchens, workshops, and office furniture. Unlike concealed undermount runners, this runner is screwed visibly to the side of the drawer box.

This guide provides the technical specifications, installation dimensions, and load limits required for the correct planning and fitting of H45 runners.

Key Purchasing Criteria for Full-Extension H45 Runners

Choosing the right fittings depends on the physical dimensions of the cabinet and the intended application. Three factors determine compatibility.

1. Installation Dimensions and Tolerances

The side-mounted ball bearing guide requires an exact installation gap between the internal cabinet wall and the outside of the drawer.

• Side space requirement: An H45 runner is exactly 12.7 mm thick. For smooth running, an installation gap of 13 mm per side is calculated in practice.
• Calculating drawer width: Clear internal cabinet width minus 26 mm gives the exact external width of the drawer.

The installation is like clockwork – a millimetre deviation in width and the runner will jam or run unevenly.

2. Cabinet Depth and Nominal Length

The nominal length of the runner must match the available depth of the furniture cabinet. The runner must never be longer than the clear internal cabinet depth.

• For a cabinet with an internal depth of 500 mm, one typically selects Drawer runners 450 mm or a maximum of 500 mm, provided the rear panel construction permits.
• With a full-extension runner, the nominal length corresponds exactly to the extension travel. A 450 mm runner can therefore be pulled out by a further 450 mm from the cabinet.

3. Load Capacity

Load capacity is specified in kilograms and always refers to a pair of runners under an evenly distributed load.

• Standard H45 runners feature a load capacity of 30 kg to 45 kg. This is sufficient for clothing, cutlery drawers, or office stationery.
• For tool cabinets or large pan drawers in the kitchen, Heavy duty drawer runners are required. These reinforced variants carry 80 kg, 100 kg, or more, but often have a wider profile or thicker material gauges.

Overview of Types and Mechanisms

In addition to pure dimensions, the integrated mechanisms define the convenience and function of the drawer. It is important not to confuse these mechanisms, as they operate in technically opposite ways.

Runners with Soft-Close

A system with Soft-Close brakes the drawer along the final centimetres of closing travel and pulls it gently and silently into the final position. The integrated damper (usually an oil-pressure or air-pressure cylinder) absorbs the kinetic energy. Drawer runners with soft close are the standard in modern living and kitchen areas.

Runners for Handleless Fronts

The Push-to-Open mechanism (often called tip-on) enables the drawer to open with a light press on the front. A tensioned spring in the runner then pushes the drawer open by a few centimetres so that it can be pulled fully open by hand. Drawer runners push to open strictly require an activation travel of 2 mm to 3 mm between the front and the cabinet. Important: On H45 runners, this function cannot technically be combined with Soft-Close damping.

Runners with Self-Closing Action

A simpler variant is a basic self-closing mechanism without a damper. Here, a spring engages over the final centimetres and pulls the drawer shut. Drawer runners with self-closing action close reliably, but will slam audibly against the cabinet if closed with too much momentum, as there is no damping component.

Which Full-Extension Runner for Which Scenario?

The decision for a specific runner follows clear technical requirements:

• For heavy pan and larder drawers: Choose Drawer runners full extension in the heavy-duty specification. A high load capacity prevents the front from sagging when fully extended.
• For deep cupboards in the workshop or garage: Long variants such as Drawer runners 600 mm are ideal here. In dusty environments, avoid sensitive damping mechanisms and choose robust standard runners.
• For shallow bathroom furniture or chests of drawers: For low cabinet depths, choose Drawer runners 300 mm. For a clean look without handles, the Push-to-Open variant is the right choice.

Installation Advice and Required Tools

Fitting H45 runners requires precision. The runners are usually separable, which significantly simplifies installation.

Required Tools

• Cordless screwdriver with a PZ2 or TX15 bit
• Tape measure or folding rule
• Pencil and try square
• Chipboard screws (typically 3.5 x 16 mm with countersunk head) or Euro screws (6.3 x 13 mm) for pre-drilled hole patterns.

Installation Steps

1. Separate the runner: Pull the runner out completely. Operate the small plastic release lever inside to detach the narrow drawer profile from the wide cabinet profile.
2. Mount the cabinet profile: Screw the wide profile to the inside wall of the cabinet. In ready-made furniture, use the System 32 (32 mm hole spacing). The front edge of the runner is positioned flush or set back 2 mm from the cabinet front edge.
3. Mount the drawer profile: Screw the narrow profile centrally onto the outside of the drawer.
4. Insert: Guide the drawer with the fitted profiles horizontally into the cabinet profiles and push it backwards with gentle pressure until it clicks into place.

Frequently Asked Questions (FAQ)

What is the difference between full extension and partial extension? A full-extension runner pulls out to 100% of its nominal length from the cabinet. The drawer contents are completely visible. A partial-extension runner stops after approximately 75% to 80% of travel, leaving the rear part of the drawer inside the cabinet.

How do I measure the required drawer runner length? Measure the clear internal depth of the furniture cabinet from the front edge to the back panel. The runner must be at least 5 mm to 10 mm shorter than this measurement. Then measure the depth of the existing drawer box. The runner length should correspond to the drawer depth.

Why does the drawer jam after fitting the H45 runner? Jamming almost always indicates incorrect installation dimensions. If the drawer is wider than the clear cabinet width minus 26 mm, the ball bearings are compressed too tightly at the sides. Mounting the runners out of parallel or not strictly level will also cause binding.

Can I replace an old roller runner with an H45 ball bearing runner? Yes, this is generally possible, but requires checking the installation gap. A classic roller runner often requires 12.5 mm of space per side, whereas the H45 runner requires 12.7 mm to 13 mm. If the drawer fits too tightly, its width may need to be adjusted.

Are there H45 runners with both soft-close and push-to-open? In the standard 45 mm height, these two systems are mechanically mutually exclusive. Highly complex undermount systems exist that combine both, but for side-mounted ball bearing runners you must choose one of the two functions.

Suitable Products and Categories for Your Project

To find the right runner for your specific piece of furniture, measure the cabinet precisely and determine the weight of the contents.

• For standard cupboards and chests of drawers, you will find a broad selection under Drawer runners full extension.
• If convenience is the priority, explore the Drawer runners with soft close category.
• For building workshop trolleys or heavy pull-out platforms, filter directly for Heavy duty drawer runners.
• If you need replacements for compact furniture pieces, lengths such as Drawer runners 300 mm are often the ideal size.

When ordering, always check that products are supplied in pairs and verify whether suitable fixings are included or need to be ordered separately.