Homebrew geared hubs?

Has anyone here tried there hand at designing an alternative to the Schlumpf? I’m curious what the exact difficulties would be.

Wouldn’t a Ravigneaux gearset be fairly easy to implement and allow for 3 gears (and reverse if you’re a masochist)? The Sturmey-Archer also looks interesting and fairly simple. Having said that, I know nothing of geared hubs, transmissions, gear sets or anything of the like.

Would the the biggest issue just be changing gear under torque?

It’d be cool to draw up a design with CAD and 3d print a prototype and maybe CNC a version if the prototype works out. Has anyone tried anything like this?

started my 3 gears hub project 7 years ago, 3D CAD still on going; may be one day …

You should open source it. What gear ratios were you shooting for?

Anybody who’s ridden a schlumpf knows this… You can’t shift it while under torque. You have to “float” over the pedals. It will let you hit the button, then when you let off the pedal pressure it will shift.

I’ve never ridden a geared hub honestly. So in that case, the torque is not a major issue assuming one can learn to float just long enough to change gears?

I think the guy that’s done the most work on alternative hubs (on this forum, anyway) is Justin. Look up Justin LE in the search box, and you’ll see his projects described.

I believe that Greg Harper built a couple geared hubs before Florian Schlumpf started producing his. The Schlumpf’s big advantage is the ability to shift on the fly. I think Harper’s plans are on the internet somewhere or I am sure he would give them to you if you sent him an e-mail/PM.

I have seen a few other one-off examples on the forum, all functional works of art.

Justin has been doing some really cool tinkering incorporating a Sturmey-Archer S3X (three speed “fixie” hub) into a unicycle and just recently building an electric assist geared hub. Great stuff if you ask me. :slight_smile:

Thanks for the info. A little off topic, but what does the electric assist hub even do?

Already shared here

This is the thread all about it :wink:

It provides you an assist like on ebike. You can definitely climb easier or just go faster on flat.

There was also Christoph riding a geared hub of his own during last Unicon marathon.