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An open source variable tooth bike sprocket


Software developer Jason DeRose used open tools to realise his obsession: building a variable tooth sproket for his bike. He used only open tools to design it, and has open sourced the design.

James Raymond writes:

Jason DeRose is a software developer currently working on an open source video editor Novacut, but a while back he designed a variable tooth sprocket for bikes by writing his own software and some python scripts in blender to build a model. He considered applying for a patent when he originally developed it, but has just recently decided to release all of his work under an open license. He shows off his design in this video.


About Author

Bart Veldhuizen

I have a LONG history with Blender - I wrote some of the earliest Blender tutorials, worked for Not a Number and helped run the crowdfunding campaign that open sourced Blender (the first one on the internet!). I founded BlenderNation in 2006 and have been editing it every single day since then ;-) I also run the Blender Artists forum and I'm Head of Community at Sketchfab.


  1. John D Smith II on

    Jonathan Williamson... Is that you?... unsuccessfully disguising your voice?? Lol Hehe, just kidding. But, uhhhh, wow! I'm sure Bart will have a special place for you on that fancy new Blender Network coming up:) Fancy stuff dude!

  2. Kirill Poltavets on

    Awesome! Very generous, James!
    I'm not too much into bikes but I guess it's a variator for bikes, isn't it?

  3. yeah ! take it to SRAM or shimano so would see your design on the bikes . Oh yes get a patent stuff too so .. you know :)

  4. Having watched all the Tour de France coverage, it amazes me that the derailleur system still hasn't been bettered. I would love to have a truly continuously variable gearing system, where there is only one overall adjustment to match your preferred cadence.

    • A continuously varaible system won't be possible as long as people are using a chain-and-sprocket system since the number of sprockets is finite. This system is the next best thing and could be fully automatic as well.

    • No continuously variable system Can handle that amount of torque Without being made how much more expensive materials And way more mass. his design is excellent it just can't be as strong as a regular sprocket without it costing 20 time's as much.

  5. Simply brilliant! And very altruistic of him to open-source the design since we will hopefully see this system being picked up by lots of bike manufacturers around the world.

    • My sister's car is a Ford Freestyle and has a continuous variable transmission. The design so far as I've seen is very slick and straightforward with very few moving parts compared to a regular transmission. My skepticism for the variable tooth sprocket is that it's so mechanically complex and has so many parts that for the average user would be just as hopeless making repairs as the typical watch owner. But it is cool.

    • There would probably be more if wacom would offer better linux support. I know that getting pressure working is the only thing holding me back from taking the plunge.

  6. Not only "open source" design, but also free and copyleft as it is GPLv3, what ennobles the author and makes the design and the source more useful and the act more ethic than simply opening the source, so they are two different things.
    That touch should be valued in one of the most important pages about blender.

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