Originally Posted by makeinu
And what are typical mechanical losses? 1 watt, 10 watts, maybe 100 watts for a rubbing brake? Think about it this way: a bicycle that is even 0.001% (one thousandth of one percent) ergonomically inferior is as inefficient as a rubbing brake. Muscular losses are clearly the overwhelmingly dominant source of inefficiency. Mechanical losses aren't even worth considering.
I think this part of your math is off, too. Sorry.
A typical 155lb human can generate about 160 watts of usable power when cycling. If a 0.001% drop in ergonomics reduced that output by 1 watt, then a 0.16% reduction in ergonomic efficiency would bring the cyclist to a dead halt. Or am I missing something?
Actually, the single biggest factor affecting performance is drag.
Lowering your handlebars doesn't make you faster because you're in a more ergonomic position; it makes you faster because you have lowered your drag coefficient. As far as I know, you can place your body in a fairly wide variety of positions and still push close to the same amount of power to the pedals -- assuming that the saddle-to-pedal distance remains consistent, of course.
Consider the recumbent. Recumbents, especially with fairings, are significantly faster than traditional bikes on the flats. Is it because you're in a better ergonomic position? Nope; it's almost all aerodynamics. In fact you're in a worse
ergonomic position, if you haven't yet developed the different muscle groups utilized by the recumbent position.
(Runners also have a higher drag coefficient than cyclists, by the way. A typical cyclist will have a Cd of 0.9, a runner is more like 1.0 - 1.3. I.e., it's not all just biomechanical, other factors are present as well.)
Friction and inefficiencies in the transmission are less important than drag, but still there -- and given the latitude of riding positions that allow you to generate power, probably more important in a bike-to-bike comparison than ergonomics. I'd imagine that ergonomics have more impact for rider comfort
than for power generation. Meanwhile, mechanical factors could easily soak up 5%, possibly even 10% of your power.
So, back to the Moulton.
Let's assume the smaller wheels produce less drag (performance +) but result in a harsher ride, thus necessitating suspension (performance -). I can see how these two factors can even out. Then, we have the increased rolling resistance of the tires, and in some cases increased drag of the frame. I'm guessing it's a wash.
If anyone is willing to drop $11k for one of these bad boys, they can spring the extra few grand to stick it in a wind tunnel and test it, right?