Ratio Technology has launched the mechanical Mech 1x rear derailleur, priced at £295, offering direct-mount and hanger-mounted options. It can work with a range of 12- and 13-speed cassettes with different gear spreads from both Shimano and SRAM.
The brand says it’s the first derailleur manufactured in the UK for 60 years, with metal components made at its factory in the Lake District and nylon parts made using 3D-printing in Kent. The Mech can be fully rebuilt using only a multi-tool.
Ratio director Tom Simpson says its performance should rival electronic systems, but with a lower weight. He suggests poor mechanical shifting is caused not by cable drag but by friction in the derailleur, so Ratio has used quality stainless steel bearings to ensure low friction and resist wear.
We covered the new derailleur back in September, but it’s now ready for launch.
Multiple cassette compatibility
Best known for making devices to adapt cable-pull ratios to enable different brands’ drivetrain components to be used together in a mix-and-match system and its replacement derailleur parts, the Mech is Ratio’s first full derailleur. It can be attached to your bike frame similarly to SRAM T-Type derailleurs and is compatible with UDH dropouts or can be hanger-mounted. It can also be converted between the two.
Ratio built a series of test prototypes that it rode during the winter of 2024-25 to prove and refine the design, subsequently adding a clutch and the interchangeable cable-pull adjuster fins that enable the Mech to be set up to work with different levers.
While SRAM’s derailleurs lack a B-screw or limit screws, they’re present in the Ratio derailleur. Ratio says this was a starting point for its design, as it 3D modelled a range of different cassette options to choose a derailleur geometry that maintained a consistent B-gap when shifting across the cassette.
So, while SRAM T-Type and gravel Full Mount derailleur users are restricted to a single cassette, Ratio’s system can be used with a range of cassette gear spreads. Along with the adjustable cable pull, this opens up compatibility not only with SRAM, but also Shimano mechanical shifting and across both 12- and 13-speed road and MTB platforms.
When we asked whether the direct-mount option might infringe any SRAM patents, Simpson told us: “SRAM’s IP protects the novel and innovative installation process for their Full Mount derailleurs, in which the friction from the clockwise bolt rotation rotates the entire derailleur back to a pre-set cage position to set the derailleur orientation and B gap.
“As we understand it, there is no protection against the concept of mounting a derailleur coaxially with the rear axle; it is not novel, as there are a number of earlier examples, and it is arguably not inventive as the step towards ‘direct mount’ is an obvious one on various elements of the bicycle (the most obvious being the chainring).”
Ratio Mech derailleur options and prices
The Ratio Mech derailleur is available for direct or hanger mounting, with cage lengths for 46t or 52t maximum cassette sizes and with a choice of seven cable fins. Together, these are claimed to offer compatibility with most 12- and 13-speed 1x drivetrains. Ratio says it will add more 11-, 12- and 13-speed options in future.
It says the Mech is designed for easy setup and can be rebuilt using only a multi-tool. It also offers a Cage Stop feature, which locks the derailleur in position for easier wheel removal. At launch, the Mech will be available in black only, with silver to follow. Sadly, though, you're going to have to wait for the blue option.
The Ratio Mech derailleur is priced at £295 / $388 / €334 / AU$592.
