Thread: Weird trike
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Old 02-21-07, 04:48 PM
  #5  
Doug5150
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Originally Posted by ppc
Well yeah, if you put an angry gorilla in the seat, it'll do 60mph no problem. Seriously though, a bike goes as fast as you push on the pedals, so speed claims are nonsensical.

About that lever system : it's be tried again and again on bicycles and never sold, because it's a proven fact that it's less efficient than rotary cranks, for two reasons :

- It takes energy to start and stop your legs twice per pedaling cycle. This energy is totally wasted with a lever system, it's partly converted into rotary motion with standard cranks.

- Only newbies put energy in a bicycle chain strictly by pushing down. Good cyclists, when they want to go fast, pedal in circle and power the cranks during most of the rotation. The lever system forces you to adopt a dud pedaling style.
I think it's not been successful just because in most attempts (of a lever-pedalling system) it's been significantly heavier than a regular crank system. Recumbent riders tend to be more tolerant of weight than upright riders, if it pays off in efficiency or comfort over the long run however. I don't know how the Sherer attempt stacks up, not having ever seen or tried it first-hand.

As to the efficiency, what "top pros" do almost doesn't matter to the rest of us. The question is, would it make a casual rider faster? It could very possibly be more efficient over an actual ride, if the lever system allowed using different pedal strokes and leg extensions (which it would seem to do). Lots of shorter pedal-strokes for high-speed cruising, and fewer, very-long pedal strokes for powering up hills. You cannot get that with a crankarm, because the crankarm is always 175mm or 170mm or 180mm.

....It is a strong suspicion of mine that using the same pedal stroke and leg extension all the time is not most efficient, but that we have not yet seen any bicycle that worked well enough to demonstrate the advantage. Much like how if you are jogging/running, you do not use the same pace or distance between steps all the time.
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