Those Rohloff hubs look nice! I never really looked at them before this thread, here is the info on the sprockets you can use. I wonder why they don't make a shifter for drop bars though.


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Smallest permittable sprocket ratios
The sprocket ratio on the Rohloff SPEEDHUB 500/14 (e.g. 42/16) converts the slow rotational speed at the crank into a fast rotational speed at the sprocket and reduces the input torque for the Rohloff SPEEDHUB 500/14 in the same proportion. To prevent overstraining the hub, a minimum sprocket ratio of 2.35 must be used. With the available sprockets these minimum ratios are achieved by: 40/17, 38/16, 36/15 and 32/13. This resembles a derailleur transmission of 22/34. Larger chainrings can be used without exceptions.