The gearshifter that doesn't understand brands: Ratio Mech arrives as the most versatile derailleur on the market

The English company Ratio Technology, specialized in turning impossible transmissions into functional combinations, has just presented the Ratio Mech, its first complete rear derailleur, a mechanical 1x model that comes with a very unusual ambition in this segment: to rival the precision of electronic systems, offer almost universal compatibility, and, for the first time in 60 years, be 100% manufactured in the United Kingdom.

Ratio Mech: the British derailleur that takes on electronics and breaks the barriers between Shimano and SRAM

The Ratio Mech arrives after more than five years of creating kits to adapt shifters, cassettes, and derailleurs from different brands. This time, the project is entirely its own from start to finish. Designed, machined, and assembled in the Lake District, with nylon parts produced in Kent using 3D printing. A 100% British product with a clear message: mechanics still have a lot to say.

A derailleur that doesn't commit to anyone: Shimano, SRAM, 12 or 13 speeds, direct mount or traditional hanger...

What distinguishes the Mech is its open philosophy. Ratio has designed it to work with almost any of the most common options available today. This derailleur is compatible with Shimano and SRAM cassettes, 12 and 13 speeds, for MTB, gravel, and road, works with the mechanical shifters of both brands, and has the possibility, thanks to the great combination of parts, to configure it practically as one wishes.

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Additionally, it is offered in both Full Mount version, directly anchored to the frame for models compatible with UDH, and with a traditional hanger, and can be converted from one to the other with a small kit.

In a scenario where SRAM's Full Mounts require a single cassette architecture, Ratio has gone exactly to the opposite extreme. The geometry of the Mech is optimized to work with different cassettes thanks to a set of simulations in Python and the combination of its components and pulleys.

A mechanical shift that changes as well as an electronic one

Tom Simpson, director of Ratio, explains it straightforwardly: “Mechanical shift failures are not due to the cable, but to the friction of the derailleur itself”. To solve this, the brand has opted for a premium approach: all moving parts rotate on stainless steel bearings, reducing friction and degradation over time.

The logic is simple: low friction + tight tolerances + optimized geometry = a mechanical shift that, according to Ratio, is on par with the performance of electronics, but with less weight and total reparability.

Modular, repairable, and designed to last

The Mech is built with machined parts in aluminum 7075 and 6082, a proprietary clutch, and a completely modular design.

Everything can be disassembled with a multi-tool, including the extraction of the clutch or the change of the cage, which is done with a single T25 screw without the need to pre-tension the spring.

Among the interesting details:

• Cage Stop: quick locking system for the cage to facilitate wheel removal
• Engraved marks on the derailleur itself to adjust limits
• Universal cable routing, without tight bends.
• Two cage lengths: 46 and 52 teeth.
• Weight: starting from 340 g

To validate the design, Ratio manufactured a fleet of prototypes that were tested throughout the winter of 2024-25 in cyclocross, enduro, multi-day routes, and all kinds of British weather. It was during this process that they fine-tuned the clutch, modularity, and the conversion system between mounts.

Price and availability

The Ratio Mech derailleur initially arrives in anodized black, with a silver option to follow.
Its official price starts at €328 and varies depending on the multiple available options (Full Mount or hanger, short or long cage, and any cable guide).

The Ratio Mech is one of the most ambitious mechanical launches in recent years. Its proposal is clear: a single derailleur capable of working with almost any modern shifter and cassette, fully repairable, with high-end performance, and without ties to any brand.

For those looking to keep their mechanical transmission alive, combine components without fear, or move away from the most common brands, this could be one of the products of the year.