Recent content by bike-nerd

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    The Physics of Power on a Bicycle

    I guess I was looking more for the "how" and "why" that variation takes place, why those variations appear to be larger in standing vs seated position, - and trying (and failing, I think!) to understand the physics behind it all... But I think I've taken up enough of your time on this topic! :)...
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    The Physics of Power on a Bicycle

    ooof! 1500 watts... It's actually that variation/oscillation in force & power that I've been trying to get at all along - I just don't think I explained it very well...
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    The Physics of Power on a Bicycle

    Thanks for the link - interesting stuff!
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    The Physics of Power on a Bicycle

    This post is mainly about pedaling a recumbent bicycle, but srcoll most of the way down to the section titled "Pedaling Standing" Here's another discussing the same graphs, plus another interesting graph showing an undulating pattern of pedal force when force for each leg is measured...
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    The Physics of Power on a Bicycle

    And I still think you're not quite understanding my question... Maybe resistance isn't the correct term. Maybe you can enlighten me as to what the right term should be. But when you shift into a larger gear - you have to press harder to turn the pedals at the same rate. Maybe there is a...
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    The Physics of Power on a Bicycle

    I'm going to rephrase the question to clarify what I'm asking. When a cyclist pedals a bicycle in seated position, they apply pressure to the pedal to create torque at a relatively constant rate around the full circumference of the pedal stroke. The resistance - or gearing - of the bicycle...
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    The Physics of Power on a Bicycle

    Yes - there's a fly wheel and a resistance unit - either a brake pad or magnetic resistance unit. It occurs to me that perhaps the question I should have been asking all along is what happens to torque & angular velocity, since that's what the power meter is measuring.
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    The Physics of Power on a Bicycle

    I'm not exactly sure I'm answering the question you're asking - but on a bike, "resistance" is changed by shifting gears. To maintain the same cadence when you add "more resistance" (shift to a bigger gear), you need to apply more force to the pedal (apologies if I'm using the wrong terminology...
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    The Physics of Power on a Bicycle

    But isn't "FORCE" part of the power equation? In some ways - standing, shifting your weight over the pedal, and pressing down hard is a little like that axe falling. The input energy is expended in a shorter time. In your example - if you could measure the torque of the axe falling - would...
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    The Physics of Power on a Bicycle

    See - THAT'S what I'm getting at. That "dissipating effort" when you stomp on the pedal WITHOUT adding resistance.
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    The Physics of Power on a Bicycle

    I completely get all of that. But that's not really what I'm asking about. In order to put out the massive amount of power riders put out in say, a final sprint - they need to be in a big gear so they have enough resistance to apply that force to. It's impossible to sprint - impossible to put...
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    The Physics of Power on a Bicycle

    Thanks - that all makes perfect sense. The observation I'm talking about is actually what appears as a brief drop in power (as reported on the power meter) when the rider stands. It usually comes back up (at least to some degree) after a few pedal strokes, unless resistance is insufficient and...
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    The Physics of Power on a Bicycle

    Thanks all for your analysis! I am talking about a strain gauge power meter on a stationary bike - so we can ignore factors like aerodynamic drag for the purpose of this discussion... In particular, when riders shift from seated to standing WITHOUT ADDING RESISTANCE, especially if resistance is...
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    The Physics of Power on a Bicycle

    Thinking out loud here... So - there is a certain amount of power that is required to keep a bicycle moving at a constant rate of speed. The real question here is - where does that power come from, and does that change in seated vs standing position? Here's my thinking - when seated, the power...
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    The Physics of Power on a Bicycle

    I'm not sure I'm expressing the question I have very well... I'll try again... Let's assume we're talking abut a stationary bicycle. In seated position, the rider's body mass is not, for the most part, applied directly to the pedal. Force is applied in a more circular fashion throughout the...
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