It appears that a Shimano Gearbox is well underway and could lead to a major shift in drivetrains for both road and mountain bikes…

Having spent a lot of time on Rohloff and Pinion drivetrains, I’m well aware of the downsides that internally geared systems bring to the table. Most notably, weight, drag, and proprietary housings when speaking of frame-mounted gearboxes. And while derailleur-based drivetrains are advancing year over year, and becoming lighter and more efficient, with wider ranges, internally geared drivetrains seem to remain evolutionarily stagnant and have yet to be widely adopted.

That could change very soon. BikeRadar editor Jack Luke unearthed a new cycling-related filing from the depths of the US Patent Office yesterday. This particular document had the abstract title “Sliding Component and Bicycle Internal Transmission Device” and was filed by by Shimano Inc. In his extensive report on the filing, Luke reveals all the inner workings of the “gearbox,” a word that wasn’t used in the patent, which was probably a deliberate attempt to conceal news that the world’s biggest bicycle component manufacturer has a 13-speed internally geared transmission in the works.

In a nutshell, the patent, according to Luke, describes a sealed gearbox that substitutes heavy cogs—prone to superfluous drag—with a lightweight roller chain design consisting of two 7-ring “cassettes.” The cassettes, or “transmission members,” are lubricated with a new engineered fluid, which Shimano talks about extensively in the document. The gearbox is controlled with a programmable electronic shifter that’s is also described within the filing. Apparently the drawings are quite advanced, suggesting that Shinamo has possibly moved the project well into prototyping phase, and maybe even close to production. Here’s a link to the patent if you want to completely nerd out, or you can find a couple photos below and read the full report over at BikeRadar.

  • Shimano Gearbox drivetrain
  • Shimano Gearbox drivetrain
  • Shimano Gearbox
  • Shimano Gearbox drivetrain gear ratios



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