castlerobber
Zen MBB Master
3. With the movable bottom bracket (MBB), how would you go about fitting an Alfine or Rohloff internally geared hub (IGH)? I like to have options, even if I mention a front derailleur above. I assume that you would fit the cranks to the rider, shorten a chain to match that crank position and then tension the chain with the movement of the front boom. Am I missing anything?
3B. Are there any known issues with using an IGH on a front wheel drive (FWD) recumbent?
3) Cruzbike used to spec the SRAM DualDrive IGH on their Quest (predecessor to the current QX100). I assume the Alfine would work in similar fashion. Don't know enough about the Rohloff to say.
The distance between the hub and the bottom bracket (cranks) is fixed, just as on an upright bike, by the length of the chainstay. Adjusting the boom to fit the rider's leg length doesn't affect chain length or tension.
3B) The only issue I'm aware of is that it makes the front triangle a little heavier. Personally, I like having an IGH on my Q. I can adjust it for other riders to try out, without worrying about throwing off the adjustment of a front derailleur. Not to mention the ability to shift while stopped.
You could even use an internally-geared crankset such as the Patterson Metropolis 2-speed. I had one on a recumbent trike and was pleased with it.