Originally Posted by
Yoshi
Not entirely true. First off there is a significant (ballpark I'd guess between 2 and 5%) gain in efficiency by having a direct drive with no derailler and a good chainline.
Second it's easier to pedal through deadspots in your rotation on a fixed-gear which helps when your climbing at low-cadence/high-gear.
Note that I was comparing a fixed gear and SS so chainline and derailleur are irrelevant. They are of extremely minor overall significance anyway.
Second of all, a fg does not help you pedal through deadspots unless you are being extremely sloppy. When you pedal a freewheel bike, does the freewheel click everytime your pedal hits 12 o'clock. It shouldn't. The pawls should be engaged the whole time, unless you are deliberately coasting. For a normal pedaling stroke, there is no complete dead spot. If you are pedaling properly (i.e. your legs are spinning the cranks through the full rotation), it makes no difference if you are pedaling a fg or freewheel.
If you truly do have a dead spot when you are pedaling uphill (unlikely unless you are seriously lazy), your are loosing momentum and basically making things worse. If thats the case, switching to a freewheel to help you learn to pedal through the dead spot will actually make you climb more efficiently.