The Binary Gear is a 2-Speed Bottom Bracket Gearbox

MagneticDays is an Italian equipment manufacturer with a background in resistance training machines and trainer components. With their first foray into the outdoor cycling world, they’re unveiling a new project: the Binary Gear, a two-speed gearbox that integrates directly into the bottom bracket of an existing frame. With a cable-actuated shifter, you can switch between a 1:1 ratio (same as a static ring) and a 1:1.25 ratio (chainring rotating 25% faster than cranks).

If you take a look at the video below, you can see the increase in gear ratio that the Binary system can provide. There’s also a quick shot of the cable actuation that happens around the bottom bracket.

The one standards hitch that the Binary system runs into is the bottom bracket standards it fits within. At this point, the gearbox can only fit into T47 and PF46 bottom brackets, as the outer diameter of the gears are too large for smaller BB shells. The team at MagneticDays says there’s a smaller BSA68 version in the works, following the Kickstarter launch.

Speaking of Kickstarter, that’s the avenue by which the Binary Gear is set to come to life, with a $32,000 USD goal to get things off the ground. On their Kickstarter page, MagneticDays is featuring some shots of the prototyping process, which is one of the few glimpses into the inner-workings of their novel design.

Cable actuator and a shifter pod. It’s unclear what the flatbar shifter will look like, but this is a reasonable form factor.

Some of the internal gearing, and an early version of the crankset.

The cranks they’ve developed in tandem with the project have another interesting trait, beyond their integration with the gearbox. They’ve added a 3-position flip chip at the pedal threads, allowing you to change the effective crank length by simply removing the pedals. This gives the user the option to run 170, 172.5, or 175mm cranks, to suit their specific fit. Obviously those lengths are biased a bit towards the road/gravel end of the fit spectrum, but it wouldn’t be too hard to shorten things up and better cater to mountain bikers.

Visually, this non-drive side actuator is the only thing out of the ordinary.

There isn’t much information on the Kickstarter page about exactly how the gearing works within the Binary, but from what we can tell it’s a series of toothed cogs translating movement from the cranks to the chainring. Drag is typically a downside that comes along with any sort of mechanical gearbox, so it’s safe to assume that there will be some here, though no numbers are quoted in the campaign.

The current pledge price to get a Binary Gear setup is €267, with an estimated final retail price of €890.

You can find more information on their Kickstarter page.