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Re: That moment of inertia video on Facebook [Titanflexr] [ In reply to ]
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I'd be willing to bet the aerodynamic gains of putting what is effectively a large "splitter plate" more completely behind the rider was of more benefit than any inertia effects...not to mention the lower Crr of that much bigger of a diameter wheel.

http://bikeblather.blogspot.com/
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Re: That moment of inertia video on Facebook [Titanflexr] [ In reply to ]
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Titanflexr wrote:
There is a very small oscillation in speed (since pedaling is a pulsed power input). Ironically, a bike with higher inertia, will minimize the amplitude of these oscillations, which would result in a lower aerodynamic drag. This was Moser's justification for using a massive rear disc when setting the hour record. Of course this effect is so minor, I doubt it's even worth 1sec./40K.
That may have been the justification but it doesn't make it the correct one.

The main speed variations on the track are transitions between straights and turns (and straights again). Variations in bike speed during a pedal stroke are very small.

Titanflexr wrote:
That 5sec. video should be 10sec, showing how the wheel with the higher inertial moment decelerates less on an upward slope, and catches the first wheel.
Indeed.
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Re: That moment of inertia video on Facebook [jackmott] [ In reply to ]
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jackmott wrote:
Well more importantly is how the smaller 90 corner accelerations are overall *Easier* with a heavier aero wheel anyway.

About the only time this question even comes up is choosing tubies vs clinchers, (or maybe Flo vs ENVE) that is the only time intertia would be very different at the same degree of aeroness. But even then the weight hurts you 10 times worse than the inertia.



KevP wrote:

It will also be able to show why the smaller 90 deg corner accelerations don't add up to much, or the smaller accelerations over the minor elevation changes, passing etc.

Do I not understand what inertia is, or is this goobly gook? More mass=more weight,=more inertia, assuming a the same speed and g, no?
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Re: That moment of inertia video on Facebook [Tom A.] [ In reply to ]
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Agreed. Pointing out that it was the rationale/excuse Moser used for selecting the oversized disc.

ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)
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Re: That moment of inertia video on Facebook [corneliused] [ In reply to ]
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corneliused wrote:
jackmott wrote:
Well more importantly is how the smaller 90 corner accelerations are overall *Easier* with a heavier aero wheel anyway.

About the only time this question even comes up is choosing tubies vs clinchers, (or maybe Flo vs ENVE) that is the only time intertia would be very different at the same degree of aeroness. But even then the weight hurts you 10 times worse than the inertia.



KevP wrote:

It will also be able to show why the smaller 90 deg corner accelerations don't add up to much, or the smaller accelerations over the minor elevation changes, passing etc.


Do I not understand what inertia is, or is this goobly gook? More mass=more weight,=more inertia, assuming a the same speed and g, no?

This is true for objects traveling in a straight line. Objects that are rotating also have an rotational inertia (similar to mass, but in a rotating context) based on their mass and how far that mass is from the axis of rotation.

Think of a figure skater doing a spin. As they move their arms/legs in they spin faster, even though their mass hasn't changed.



ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)
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Re: That moment of inertia video on Facebook [Slowman] [ In reply to ]
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Last fall I made a computational bike model that included a oscillating sinusoidal power input. I put in parameters similar to a plot found in High Tech cycling for the power fluctuations of a typical cyclist. The predicted oscillations in velocity at steady state were minuscule on the order of 1/100 to 1/10 of a mile per hour. Higher inertia was of no benefit in the model.
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Re: That moment of inertia video on Facebook [Slowman] [ In reply to ]
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This thread gave me a headache. ;-)
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