Calculating watts per kilogram
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Calculating watts per kilogram
When one calculates watts per kilogram. Is the mass only the weight of the rider without clothing, etc.? Or is it the combined weight of rider, their clothing, bicycle, tools, water bottles, etc.?
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If you are using it for measuring your fitness then I would just take your undressed weight.
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Before or after pooping?
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Wake up, coffee + banana (maybe a small pastry portion), bowel movement, scale, kit up, then on the bike!
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For supply side, just you, nekkid, post-poop.
For demand side, you, all your kit including water bottles, and your bike.
I would say that most people most of the time mean supply side.
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I usually think of it as a trait of the rider, so it's just the rider. Your W/kg doesn't change when you change bikes. And as mentioned, since most bikes are only marginally different in weight when accounting for the bike + rider system, it only matters in very narrow circumstances.
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I usually think of it as a trait of the rider, so it's just the rider. Your W/kg doesn't change when you change bikes. And as mentioned, since most bikes are only marginally different in weight when accounting for the bike + rider system, it only matters in very narrow circumstances.
If you're trying to estimate how fast you can climb a steep road, you'll be looking at the W/kg of the whole package (rider + bike + accessories).
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Right, but my point is that in that case, the difference between a mid-range and high-end road bike is still very small compared to even a 60kg cyclist, and with two 60kg cyclists the FTP difference is likely larger than the bike weight.
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Models that estimate how fast you can climb usually have separate parameters for bike and rider weights. If someone says they have a 4 W/kg FTP they are not including the weight of their bike and kit. Your power in terms of W/kg should be independent of what bike you are riding if you are comparing the performance of riders.
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Soooo I don’t mean to be controversial but isn’t w/kg usually a measure of strength and fitness? If you make your bike lighter or leave a bidon at home, did you get stronger or fitter?
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The weight difference between a high-end climbing bike and a mid-range road bike is not very small. A decent climbing bike is easily 2 kg lighter than a mid-range bike.
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Exactly. When discussing W/kg as a measure of human performance it is literally Watts per kg of bodyweight. The weight of the bike and kit is only relevant in cycling simulation models.
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