This must begin with a caveat: The new split derailleur from Lal Bikes and inventor Cedric Eveleigh is currently designed only for high pivot full suspension bikes. But the tech is quite interesting, especially if you’ve ever busted your derailleur on the trail, or shift into high gears all the time to avoid hanging that sucker right above the rocks.
There is a video below that will describe the system very well, but, briefly, Eveleigh’s design splits the two functions of a normal derailleur: shifting and tensioning the tensioning the chain. The tensioning is accomplished via a pivoting tensioner mounted just above the bottom bracket. The derailleur, freed from having to also function as a tensioner, is then mounted right at the cassette, tucked within the frame. Nothing hanging low to bang off rocks and roots, or to be dragged through the mud. A damper maintains even tension across all gears, which should increase efficiency in the design.
Eveleigh’s plan is to manufacture the derailleur, idler pulley, and tensioning parts, through his Lal Bikes brand, and then make them available to bike makers.
From his site:
The Supre Drive is compatible with off-the-shelf hubs, bottom brackets, cranks, chains, shifters, and cassettes. Two specific requirements are a 52mm chainline and a T47 bottom bracket. The latest version of the Supre Drive works with a Shimano 10-51t cassette (although the prototype bike shown here has a 10-45t cassette). Shifting performance is the same as a full Shimano drivetrain.
The frame, however, has to be designed to accommodate this new drivetrain. Eveleigh says he’s working with one frame manufacturer now, and has plans to collaborate with others.
Because we don’t talk about Esperanto enough, it’s fun to note here the “Supre” in Supre Drive comes from the Esperanto word for “above.”