"Leo Lichtman" <[email hidden]> wrote in message news:[email hidden]...
Quoted message said:
I have an idea of a way to measure the power a rider delivers to the pedals, which I would like the rest of you to verify or criticize. When you are standing, the rate of doing work is similar to climbing stairs. Each stair tread riser is equal to the vertical distance between the pedals. The number of foot-lb/min should be equal to the cadence x 2xcrank length x weight on pedal. My first inclination was to use my body weight, but I realize that is too high, since I support the upper body on the handlebars. So, I propose to place a bathroom scale on a box, next to the stationary bike, and step on the scale in riding posture.
If I ride sitting down at the same speed, the power ought to be about the same, except that air drag will change with my posture. So obviously, I can't transfer the results at high speeds, but it ought to be fairly close on hills, where most of the power goes to climbing.
Comments?
I can ride up the same hill at 10mph or 15mph with the same cadence whether standing or seated by using different gears. The pressure applied to the pedal is too variable for determining a reasonably accurate power output.
"Philip Holman" wrote: I can ride up the same hill at 10mph or 15mph with the same cadence whether standing or seated by using different gears.(clip) ^^^^^^^^^^^^^^ I assume you mean 10 mph seated or 15 mph standing. My assumptions and calculations would apply only to standing, since your body weight is what is depressing the pedals. Since it takes approximately the same power to push you up the hill at 10 MPH, standing or seated, I seems that you could use figures based on your cadence while standing to determine your power at the same speed while seated.
"Philip Holman" wrote: I can ride up the same hill at 10mph or 15mph with the same cadence whether standing or seated by using different gears.(clip) ^^^^^^^^^^^^^^ I assume you mean 10 mph seated or 15 mph standing. My assumptions and calculations would apply only to standing, since your body weight is what is depressing the pedals. Since it takes approximately the same power to push you up the hill at 10 MPH, standing or seated, I seems that you could use figures based on your cadence while standing to determine your power at the same speed while seated.
http://anonymous.coward.free.fr/wattage/components/components.html shows some plots of power, rpm, and torque for a couple of riders on a couple of different types of rides. If you look at one of the rpm-torque plots you can see how much range there is in torque at any given fixed cadence.
