"Ron Hardin" <[email hidden]> wrote in message
Quoted message said:Walking is mostly wasted motion, and a tiny part actual useful work,
unless you're
Quoted message said:walking up a steep hill, in which case only speed matters.
Cycling is almost all useful work, and subject chiefly to elementary
physics.
Quoted message said:
One of the finest and most astounding proofs of the physicist's definition
of
Quoted message said:work is the indifference of the gear to the effort to cycle up a hill.
The cadence matters if you're after _peak output_, and then impedance
matching matters.
Quoted message said:But peak output is not long term output, and long term output depends only
on speed.
Quoted message said:You can't keep peak output up.
You may have weak muscles and strong muscles, but whichever you're using
to power
Quoted message said:the bike, only the speed determines how out of breath you get.
Ron,
For all your talk of physics and whatnot, I amazed at your ability to completely ignore what is
happening with your own body and the physics that apply there. Try a little experiment. Pick a nice
flat road. Ride down that road at 20mph in your favorite gear. Note how much effort it takes to
maintain that speed. Now drop down four gears. Ride that same section of road again while
maintaining the same speed. Note how much more effort it takes to maintain the higher cadence.
What you are ignoring is the fact that you have two lumps of flesh and bone pumping up an down and
two somewhat smaller lumps moving around in circles. It takes energy to move these. The more times
they have to be moved, the greater the energy output. Note that this all happens *before* we start
talking about forces on pedals and forces moving the system as a whole.
Take, for another example, big trucks. When the speed limit changed to 55, the cost of overland
transportation went up. Not just because of additional time needed for transportation. The trucks
were designed to cruise at 70mph and were most fuel efficient at that speed. Lowering the speed
limit forced them to drive at a speed that wasn't as fuel efficient. Their fuel costs went up
because of inefficiency and more time spent on the road.
If you take issue with this, consider the Continuously Variable Transmission. In a vehicle that uses
a CVT, the engine speed varies only between idle and a pre-set optimum rpm. Why? Because "keeping
the engine at a constant rpm allows the engineers to optimise ignition timing, camshaft design, and
manifold tuning for excellent volumetric efficiency and low emissions."
canadiandriver.comat 010508.htmOpen ↗
The beauty of a bicycle with gears is that the rider can find the optimum cadence and maintain that
cadence through a wide range of speeds. Every system has an optimum performance range, whether the
system is mechanical or biological. Ignoring this is ignoring the physics you love.
-Buck