Ratio Technology is based in Ambleside, Cumbria, UK, a bucolic area that British people know as 'the Lake District'. The company was founded in 2018 by Tom Simpson and Felix Barker.

For a number of years Ratio specialized in manufacturing small derailleur parts that could be used to convert derailleurs from the major manufacturers so that, for example, road levers could be used with ATB derailleurs, or a 2X medium ratio road derailleur could, by fitting a replacement pulley cage, be converted to a wide ratio 1X set up. There are a host of possibilities, all much beloved by irritating gear heads.

And then, in late 2025, they released the Ratio Mech. This was a complete and modular, mechanical, 1X derailleur system. By fitting different cable 'fins' and different pulley cages you could match this derailleur to any number of cycling styles using different shift levers from either SRAM or Shimano.

Ratio, as befits a company based in one of the rainier parts of Britain, places a lot of emphasis on the durability and repairablility of its Mech. It has sealed bearings at the parallelogram pivot points, is fully demountable and a genuine effort seems to be made to make parts available.