Kicking the bike backwards when standing... what's the cause?
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Kicking the bike backwards when standing... what's the cause?
Shifting ones weight forward? starting your stand with the pedal down (no force)?
/discuss
/discuss
#4
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If you have someone on your wheel, warn them you are about to stand.
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I could tell you, but then I'd have to kill you.
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In the sense of center of mass (COM), if you're COM is moving up a steep hill at 10mph and you stand, you're probably moving 90% of the bike weight (your body) forward faster than 10mph, meaning the bike itself has to either slow down or go backwards (just for a moment). Now, I suppose you could apply sufficient force just as you started standing up that you keep things moving forward.
Even if all the wheel does is slow down, someone close on your wheel could bump it.
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Because gravity doesn't go away when the road gradient is zero?
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#12
Making a kilometer blurry
In the sense of center of mass (COM), if you're COM is moving up a steep hill at 10mph and you stand, you're probably moving 90% of the bike weight (your body) forward faster than 10mph, meaning the bike itself has to either slow down or go backwards (just for a moment). Now, I suppose you could apply sufficient force just as you started standing up that you keep things moving forward.
Even if all the wheel does is slow down, someone close on your wheel could bump it.
Even if all the wheel does is slow down, someone close on your wheel could bump it.
If you're another rider, your frame of reference is your own bike. When the guy in front stands up, his weight moves forward relative to his bike, but his COM continues at the same speed. Since the bike is lighter and the COM didn't move relatively, the bike moves closer to yours.
The effect would be much smaller if we just rode much heavier bikes
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It's not so mysterious. When some people stand, the first thing they do is pull themselves forward off the saddle with their arms. When you do this, you are pulling the bike back by the handlebars. If the first thing you do is push hard on the pedals and let your legs raise you off the saddle, then the bike doesn't jump back.
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So your saying the reason a bike moves "backwards" when a rider stands on flat ground is because gravity pulls it back?
Is the correct answer.
It's not so mysterious. When some people stand, the first thing they do is pull themselves forward off the saddle with their arms. When you do this, you are pulling the bike back by the handlebars. If the first thing you do is push hard on the pedals and let your legs raise you off the saddle, then the bike doesn't jump back.
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In my previous post, I said the reason a bike moves backwards when a rider stands on flat ground is because of the law of reciprocal actions.
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it's basically the reverse of throwing your bike at the line. If there is someone on my wheel, I make an effort to stand smoothly and without throwing the bike backwards. It takes some effort.
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"When you are chewing the bars at the business end of a 90 mile road race you really dont care what gear you have hanging from your bike so long as it works."
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"When you are chewing the bars at the business end of a 90 mile road race you really dont care what gear you have hanging from your bike so long as it works."
ΛΧΑ ΔΞ179 - 15% off your first Hammer Nutrition order!
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Both of you are correct in your observations.
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"When you are chewing the bars at the business end of a 90 mile road race you really dont care what gear you have hanging from your bike so long as it works."
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"When you are chewing the bars at the business end of a 90 mile road race you really dont care what gear you have hanging from your bike so long as it works."
ΛΧΑ ΔΞ179 - 15% off your first Hammer Nutrition order!
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