Let's not forget about tandem bicycles. Some of them do indeed allow the pilot to do all the work while the stoker has a rest.
Few of them actually do this. Usually the stoker must continue to pedal (or ghost pedal) whenever the pilot is powering the bike. Much simpler.
Now, whether the power can be transferred from left hand side to right hand side in a set up that allows the stoker to rest.... yeah maybe that's all rhs drive at that point. Its what we're looking for, though? That might be the expensive thing, might even require a special BB shell built into the frame.
I cba checking it out thoroughly right now, I came here for something else and got completely distracted lol.
@CrazyDan it seems you have a simple Y arrangement there as opposed to the Z arrangement on the Shift Kit by Sick Bike Parts. That's just great. Its an ideal set up, and no obvious problems that are difficult to overcome other than it needs a JS mounted freewheel adapter for regular direction freewheel on the outer rhs JS sprocket to take power from the pedal sprocket, which you can get from SBP or Stanton, i believe.
Sprocket maximum sizes being limited by proximity to the engine or other parts, and the minimum of the freewheel adapter.
I would love to see one of these Y arrangements again. I saw just one photo of one of these, ages ago on the forum, it was a custom (long) frame bike that raced..Green bike, idk if you saw.
Engine power goes through only 2 chains and 4 sprockets with 1 reduction and 1 set of dérailleur gears (or internal gear hub that can go either way but from the 16t freewheel its going to want to be mostly reduction, and why use a IGH on such an efficient set up. Maybe a NuVi?), as opposed to the Shift Kit with 3 chains and 6 sprockets with 2 reductions and then a... gain?
Build it please! And win with it!!
![Folded hands :pray: 🙏](https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f64f.png)
![Grinning face with smiling eyes :smile: 😄](https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f604.png)