Praxis is entering the gearbox race with a bold in-house innovation. The new HiT Hinged Transmission promises smooth shifting, minimal wear, and compact design—paving the way for integration with future e-bike systems.
Praxis is well known for its OEM components, but the working prototype of a unique new gearbox took pride of place on the stand at Eurobike 2025. Praxis believes, like many, that a gearbox is the way forward for the majority of bicycles: It keeps delicate components enclosed and out of danger, and extends a bike’s service life.
The HiT Hinged Transmission has been developed entirely in-house, and uses an internal chain drive that runs over a series of hinged gear clusters. Because the hinged gears sit on top of one another, the chainline within the gearbox is kept constant. That means that the gearbox is very compact, and chain wear is minimal. The constant chain line also means that shifting under load is not an issue.
Each sprocket cluster consists of a smaller solid sprocket, and a larger outer sprocket divided into four hinged sections. The working prototype on the Praxis stand has two clusters, or four speeds, but more can be incorporated, making bigger gear ranges possible. Actuators within the gearbox work on cam sliders on the hinged sections that move them into position on the part of the sprocket that’s not in contact with the chain, allowing the chain to ramp up and down seamlessly between the two sprockets.
Praxis has already built, ridden and tested the HiT gear box on mountain and city bikes, but its goal is to integrate it with an e-bike motor. It’s looking for the right relationship to help develop what’s certainly a novel product in a space where there is a lot of interest and innovation.