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greg harper planetary unicycle hub.JPG

Wrapping up my trifecta of epicyclic gear posts today (1, 2) is this practical application from Greg Harper, a resident engineer at the University of Washington’s Center for Experimental Nuclear Physics and Astrophysics, who put together a custom epicyclic gear train for his unicycle hub. Designed for speed, the hub gives 1.5 rotations of the wheel for each rotation of the pedals.

Sean Michael Ragan

I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I write for MAKE, serve as Technical Editor for MAKE magazine, and develop original DIY content for Make: Projects.



  1. Berend says:

    I have this site in my bookmarks, and sometimes, when I need some technical simplicity and beauty, I visit it:

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