Ratio Technology has released the Mech, a fully mechanical 1x rear derailleur designed, manufactured and assembled in the UK. Sales opened on 19 November 2025 at £345, marking what the company describes as the first UK-produced derailleur in around 60 years, with machined aluminium components made in the Lake District and 3D-printed nylon parts manufactured in Kent.
The Mech targets riders who want electronic-level shifting without batteries, with Ratio focusing on reducing friction at the derailleur rather than in the cable. Stainless Enduro bearings are used in the links and jockey wheels, and the geometry has been modelled specifically for modern 1x cassettes rather than adapted from older designs.
Modularity is the headline feature, where interchangeable cable fins alter cable pull to work across a wide spread of SRAM and Shimano 1x setups in 12 and 13 speed. Seven fin options are available at launch with more planned. The derailleur is 1x specific and offered with cage lengths for maximum sprockets of 46t and 52t. Some SRAM road shifters may still require Ratio’s existing ratchet upgrade kits.
Two mounting formats are offered. A standard hanger-mount version fits existing frames, while a UDH-compatible Direct Mount places the body coaxially with the axle, which Ratio says increases stiffness. Claimed weights start at 340 g for the short-cage hanger model.
Serviceability is central to the product. The Mech can be fully stripped and rebuilt with a multi-tool, including swapping cages, replacing links or converting between hanger and Direct Mount. The clutch uses a self-contained wrap-spring design, and a single T25 screw retains the cage without the need to preload the spring. Ratio’s Cage Stop feature locks the cage forward for faster wheel removal, and on-mech markings reference a lookup table for B-gap setup.
The first batch shipped in a black anodised finish, with silver to follow. Pricing remains fixed at £345 with indicative conversions of $377, €328 and $581 AUD. International shipping starts from £11 and spare parts are listed alongside the derailleur to support long-term rebuild and repair.
