seeker333

All internal gear hubs (IGH) are less efficient at transferring power compared to derailler drive systems.

See Figure 12 on page 9 - it presents a pretty good summary of test results on a single graph:

http://www.ihpva.org/HParchive/PDF/hp52-2001.pdf

The difference in efficiency between Rohloff and Shimano 9 speed is ~3% overall. The small amount of additional drivetrain friction on a Rohloff-equipped bike is equivalent to the effort of pedaling 128 extra miles in a Transamerica tour - about 2 days bicycling for most people.

I don't believe this is much of a disadvantage to someone who's seriously considering a Rohloff hub.

I see it as an incremental detriment to touring, like carrying an extra 5 lbs luggage, using 900g tires for a reduction in flats, or using a flat bar versus the usually more aerodynamic drop bar, etc. The cumulative effect of these choices can significantly increase the difficulty of a bicycle tour.