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 Post subject: power question
PostPosted: Sun Dec 16, 2012 3:22 pm 
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Joined: Sun Jun 27, 2010 8:53 am
Posts: 245
2 riders sprinting at a similar pace, i.e. side by side....

rider 1 has 1000w and is about 72kg

rider 2 is 550w and about 53kg


someone tried to tell me today that gearing effects power???? I'm thinking BS...

I think gearing effects torque.... any info or facts to help me put him straight


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 Post subject: Re: power question
PostPosted: Sun Dec 16, 2012 3:32 pm 
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Location: Canada
well if gearing affects torque, it affects power. Whats the exact question? Why the 2 riders exemple?

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 Post subject: Re: power question
Posted: Sun Dec 16, 2012 3:32 pm 


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 Post subject: Re: power question
PostPosted: Sun Dec 16, 2012 6:31 pm 
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Gearing doesn't really affect power. maybe instantaneous power, but nothing actual. Power=torque x rpm. Increase gearing, cadence goes down, torque goes up. if your progress is the same, power is the same. no free lunch.
Two riders sprinting, the heavier rider will require more power to accelerate at the same rate as the lighter rider. Force=mass x acceleration, F=MA. A=F/M.


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 Post subject: Re: power question
PostPosted: Sun Dec 16, 2012 6:47 pm 
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Gearing on its own absolutely does not affect power, unless of course we're talking about changing cadence in which case power may change. And then of course gearing becomes irrelevant because it's cadence affecting your power and not gearing.

Torque is not really terribly relevant... A larger sprocket at the back will produce more torque around the freehub, and longer cranks at the front will result in more torque at the front around the bottom bracket - neither will affect your power output and neither are particularly relevant?


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 Post subject: Re: power question
PostPosted: Sun Dec 16, 2012 7:17 pm 
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Location: Holland
williamsf1 wrote:
2 riders sprinting at a similar pace, i.e. side by side....

rider 1 has 1000w and is about 72kg

rider 2 is 550w and about 53kg


They won't be sprinting side by side, as rider 1 will be faster. :smartass:

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 Post subject: Re: power question
PostPosted: Mon Dec 17, 2012 2:17 pm 
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yeah it was brought up after a training ride, as they both held about the same pace in the sprint.... the only thing I could come up with was aero drag for the larger rider and the weight?


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 Post subject: Re: power question
PostPosted: Mon Dec 17, 2012 9:09 pm 
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Aero drag, and it could have been slightly uphill. and the bigger dude may have been gaining a bit without it being too noticeable.


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 Post subject: Re: power question
Posted: Mon Dec 17, 2012 9:09 pm 


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