DT> No, there's no "pull" per se.  The efficiency comes from being able to
 DT> spin quickly without losing the pedals.
DC>  Actually there is quite a bit of 'pull' power available...
I can't quote, or even name the study, but there was a posting in this echo 
many years ago that a study was done with professional and amateur riders 
that measured the pull on the pedals through the stroke.  The professional 
riders did in fact have a slight pull up on the pedal as they road down the 
road, but, that was with a conscience effort to do so.  In their normal 
riding stroke, there was no pull and even some weight that was carried back 
up through the pedal stroke by the opposite foot pushing down.
I don't doubt that some pull is there at times.  When you first take off from 
a stop, standing up and pulling and pushing with both legs for the first six 
or seven revolutions, no doubt you're pulling up.  When you're running down 
the road spinning at your cruising speed, there's little to no pulling up 
even if you think you are.  Again, that was the measured result of the study 
as published here.
BTW, I'm a roadie too.  This was long enough ago that off-road didn't exist 
yet.  Remember when all the bikes in the store had drop handle bars?  :-)
                                  Dewey

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