Re: On low gears

On Feb 7, 8:21 pm, Frank Krygowski <frkry...@xxxxxxxxx> wrote:
On Feb 7, 11:12 pm, carlfo...@xxxxxxxxxxx wrote:



As for the bobbing, it's hard to ignore the much greater and therefore
faster movement of the legs as the rider's feet follow the 350 mm
pedal circle.

Carl, I'm sure you agree that cycling is more efficient than walking
on flat ground.  That's despite far greater aerodynamic losses.

Why, specifically, do you think cycling is more efficient for the flat
ground case?

A few advantages:
Variable gearing that allows for a better match between the optimum
speed of the leg muscles vs. the available force. When walking you
get to a pretty high cadence even when still walking relatively
slowly. Speeding up makes for an inefficient gait and much of the
energy is used in just swinging the legs back and forth rapidly

As you pointed out, there is the up and down motion of the center of
gravity and the energy put into raising it is not recoverable when it
lowered again.

Ability to coast on the bicycle lets the cyclist rest and still make
forward progress. The walker needs to exert significant energy even
when slowing down.

Which of cycling's advantages do you think would go away on an uphill?

All of the ones cited above.
At a great enough grade the low 'effective gear' of the walker becomes
the correct one so the cyclist no longer has an advantage in being
able to choose higher gears.
When climbing stairs or a steep hill there is no periodic drop in the
center of mass of the walker. Instead, the COM continually rises and
therefore the motion is more efficient in mechanical terms than when
walking on flatter ground.
The ability to coast on a bicycle goes away on steep grades where all
forward momentum would be immediately lost and the cyclist would fall
over.
.

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