Another internally geared crank
It isn't clear to me whether one can swap the chainrings. But given the cost of a Schlumpf Drive, an alternative is a plus.
Good development. I am a little leery of small chainrings, which wear quicker. Ability to swap out rings would be essential.
I'm willing to bet the chainring is replaceable. I t also looks like an external mechanism, as opposed to the schlumph which I believe houses the mechanism within the BB (feel free to correct me here).
The Schlumpf's actual planetary gear mech and clutch is also external but some of the gear change parts are inside the spindle.
Interesting - perhaps it could also work with larger rings :
e.g. 35 * 1 / 1.6 -> 35 / 56 - giving a really wide range to small wheeled bikes.