why can't unicyclists have it too?

[Onions]

We can, but it takes lots of manufacturing work:

3 Speed Unicycle Build

Bit of a background. In early 2008 or I got a Nuvinci CVT hub and was convinced I’d be able to hack this to work bidirectionally in a unicycle application with a jackjaft. Unlike the conventional internal hubs, the friction drive against the spherical rollers should fundamentally be able to alternate between forwards and reverse torques with no slop at all. Then you’d have the dream setup, a 300+% gear ratio with no sudden shifting. Here’s what the whole thing looks like taken apart on the ben…