Velomobile shifting diagrams

I made these to illustrate the difference between shifting a Rohloff vs. conventional derailleur/cassette system in a velomobile going at speed. According to Doug Davis at Bicycle Evolution, some novice velonauts desire Rohloffs because they offer a very wide gear range, but the larger gaps between gears make them less efficient at speed. He has data about watts and gear inches and rotations per minute, but I merely tried to convey the drama of having to upshift too fast in a 60+ pound tub:

Rohloff hub: Shifting over 14% at speed puts sudden stress on the velonaut.

For contrast, the illustration below represents a more narrowly spaced conventional rear cassette setup, like what I have on my Mango:

Conventional derailleur/cassette: Shifting in smaller increments reduces stress and maintains efficiency at speed. The velonaut’s cadence slows only slightly after shifting, and quickly returns to normal.

Maybe we’ll talk about this, and other recumbent nerd stuff, on the next Laidback Bike Report.


Author: Nina Paley

Animator. Director. Artist. Scapegoat.

2 thoughts on “Velomobile shifting diagrams”

  1. ‘Tis true, even standard 11-34+ type recumbent cassettes are generally less than 10% between shifts at the high end. Good illustration!

  2. A 14% increase … takes you from 90rpm down to 78rpm, hardly a huge strain on the rider.
    A good old three speed has a 33% increase.

    What you’ve illustrated is a Schulmpf HSD, which would be a strain on the rider if there wasn’t gearing out the back to bridge the gap.

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