Best Window Gearbox Brands for UK Homes: Trade Recommendations

Best Window Gearbox Brands for UK Homes: Trade Recommendations

Choosing the right window gearbox matters for security, smooth operation and longevity. Whether you are a trade professional stocking parts or a homeowner replacing a stubborn handle, understanding brands, compatibility and practical installation tips will save time and avoid returns. This article focuses on window gearbox choices suitable for UK homes with trade-minded recommendations and DIY guidance; it complements our wider espagnolette and window locking content at /guides/espagnolette-window-locks.

What is a window gearbox and why brand matters

A window gearbox is the small mechanical unit inside a casement or tilt-and-turn window that transfers the rotation of the handle to the locking cam and espagnolette mechanism. It contains gears, a spindle interface and often a cam or hook drive. Quality varies between manufacturers; a good gearbox gives smooth travel, accurate handle positions and long life. Poor-quality units can lead to sloppy handles, premature wear and security failures.

Top window gearbox brands for UK homes

• Roto: Highly regarded in both trade and manufacturing circles for robust gearboxes and a wide range of spindles and cams. Roto parts are commonly found in modern uPVC and aluminium windows; they offer strong technical support and good availability of replacement parts.
• GU (Gretsch-Unitas): A major supplier of espagnolette systems and gearboxes. GU gearboxes are known for solid engineering and compatibility across several handle manufacturers. They are a reliable choice for higher-security and PAS 24 applications.
• Maco: Austrian-made components with a reputation for smooth operation and durability. Maco gearboxes are common in tilt-and-turn and casement systems; trade fitters appreciate their consistent build quality.
• Winkhaus: Offers a range of gearboxes suited to both residential and commercial windows. Winkhaus components often integrate well with multi-point locking espagnolette systems.
• Siegenia: Known for precision engineering, particularly for tilt-and-turn gearboxes; Siegenia units suit aluminium and timber windows where crisp handle action is important.
• Aubi: Widely used in the UK market as a cost-effective, dependable option. Aubi gearboxes are commonly available through trade distributors and are compatible with many handle sets.

All of the above manufacturers produce gearboxes with various spindle sizes and cam profiles; for best results match the brand and part code where possible. Where an exact match is not available, ensure the replacement has the same spindle profile, projection and cam type.

Practical trade advice: what to stock and check

• Stock common spindle sizes: 7mm and 8mm square spindles cover the majority of UK casement handles; consider a small number of 10mm spindles for older or specialist fittings.
• Keep popular cam profiles and faceplate styles: trade calls often require the same cam orientation and faceplate length; carrying several common types reduces call-back visits.
• Use manufacturer cross-reference charts: most suppliers provide cross-reference guides for gearbox part numbers; this reduces mis-identification and returns.
• Check security certification: for installations that must meet PAS 24 or Secured by Design standards, use gearboxes and espagnolette systems certified by the manufacturer.
• Note warranty and support: larger manufacturers such as Roto and GU usually have better warranty processes and parts availability; this matters for long-term maintenance contracts.

DIY guidance: identifying and replacing a window gearbox

This section gives practical steps for competent DIYers; if a window is heavy or in poor condition, seek professional help.

• Identify the gearbox: remove the handle and measure the spindle square size with callipers; note the spindle projection and the number and orientation of cams. Photograph the unit and any stamped part numbers.
• Match the part: use the brand cross-reference or bring the old gearbox to a trade supplier; exact matches eliminate cam misalignment and incorrect spindle lengths.
• Remove safely: support the sash if required; remove securing screws or rivets and detach the gearbox. Keep all fixings and small parts together.
• Fit the new gearbox: grease the gearbox splines lightly with a PTFE or lithium grease; insert the gearbox and ensure the spindle aligns squarely with the handle. Tighten screws to a firm, not excessive, torque to avoid stripping or distortion.
• Test operation: cycle the handle through full travel, check for smooth movement and correct locking engagement; close and open the window several times to seat the mechanism.
• Fine adjustment: if the handle is tight or loose, check for misaligned cams or incorrect spindle projection; small spacers or shims can correct projection in some systems.

Common DIY mistakes include mismatching spindle sizes, not supporting the sash during removal and applying oil rather than grease. Oil can attract dust and wash away; use a light grease to protect gears.

Compatibility and retrofit considerations

Not all gearboxes are direct drop-in replacements: variations in faceplate length, cam profile and spindle projection matter. Where windows have multi-point espagnolette locking, changing a single gearbox may require adjustment of the locking rod or striker plates to maintain alignment. For older timber windows, confirm that the new gearbox mounting holes align with the existing preparation; some retrofits may need a small amount of timber repair or additional fixing screws.

When to call a trade specialist

Call a trade specialist if the sash is heavy, the window has multiple locking points out of alignment, or if you need compliance with security certification. A trained installer can diagnose hidden issues such as distorted frames, warped sashes or worn keepers that a simple gearbox change will not fix.

Recommended Products

Based on this article, you may find these products helpful:

• ERAB Espagnolette Window Lock Universal Lock Replacement
• Avocet Slimline Offset Window Espag
• In-Line Window Mechanism
• Offset Window Mechanism
• Multipoint Gearbox GU Old Style

Conclusion and next steps

For UK homes, Roto, GU, Maco, Winkhaus, Siegenia and Aubi are solid choices for window gearbox replacements and upgrades; trade fitters should stock common spindle sizes and cam profiles to reduce call-backs. DIYers can replace gearboxes safely with the right measurements, parts and a light greased fit. If you require a specific product match or certified security components, contact a reputable supplier or installer.

Next steps: measure your spindle size, photograph the existing gearbox and consult your supplier with the manufacturer or part number. For more on espagnolette window locks and related components see our espagnolette window locks page for technical background and fitting notes.