There's a very in-depth talk by Keith Wakeham, arguing that shifting is practically impossible with this system: https://www.youtube.com/watch?v=o9d_cBGXMwY htt

There's a very in-depth talk by Keith Wakeham, arguing that shifting is practically impossible with this system: https://www.youtube.com/watch?v=o9d_cBGXMwY https://www.youtube.com/watch?v=o9d_cBGXMwY If I understand it correctly, the issue is that the driveshaft has to move from one "sprocket" to the next in a very small amount of time at high rotational speeds of the cassette. Because of the weight of the bearings at the end of the driveshaft, a very large force is required to accelarate it.