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Does being heavier make you go faster?
#1
Thought is was well past time for a daft debate  ;D
So here goes does the urban legend of being heavier on a bike, does it make you go faster down hill?
My thoughts are no as weight as I understand either has no bearing on free fall decent or maximum velocity, although I have been wrong before  :B
I understands that the bigger you are, on average you will have stronger legs, ie more pedal power, but I'm talking freewheeling.
Please debate and be nerdy and argumentative as possible  ;D
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#2
Yes!  If it doesn't ,I've just spent 2 months off the bike  eating  Ben & Jerry's with me feet up for nothing! My theory will be put to the test soon .
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#3
"GravesendGrunt" Wrote:Yes!  If it doesn't ,I've just spent 2 months off the bike  eating  Ben & Jerry's with me feet up for nothing! My theory will be put to the test soon .

Big Grin liking the recovery plan. Ben and Jerry's super calcium diet  ;D mhhhh!
Hope it's all going well for you, and you're good to ride again soon Smile
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#4
Yes, downhill..... with most other things being roughly equal.

Weight has limited impact on falling speed & terminal velocity, but has an effect on acceleration.
A cyclist has no interest in falling speed (most of us anyway) & we don't often get to terminal velocity, therefore the biggest factors are acceleration & resistance.
With the same air resistance & friction a larger mass will accelerate faster than a lighter one.
I said "most" above as the force required to move both riders to start with cannot be equal.
"If" the hill was long enough then both riders would reach the same terminal velocity.

You also need to consider that the larger mass will be slowed less by any obstacle or change in resistance/friction & therefore maintains more of the speed gained by it's added acceleration.

[sits back & waits to be corrected]
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#5
Short answer = yes
Long answer = (shamelessly copied & pasted)

During descents, the negative slope of the hill in the power equation reflects the addition of gravitational potential energy to the power generated by the cyclist. In a freewheel (passive) descent, the cyclist's speed will be determined by the balance of the air resistance force and the gravitational force. As the cyclist accelerates, sv2 increases. Once kaAsv2 (plus the negligible power term associated with rolling resistance) increases to match giMs, the cyclist will reach terminal velocity. Any further increase in speed must be achieved by adding energy through pedaling. However, on steep hills, terminal velocities may reach 70 km·hr-1. At such high associated values of sv2, even the application of VO2max would result in only a minimal increase in speed.

Terminal velocity can be solved for in the cycling equation above by setting power at 0. If one assumes the rolling resistance term is also 0, and that there is no wind blowing (v = s), then the equation becomes:

kaAs3 = -giMs
or s = (-giM/kaA)1/2

Thus, the terminal velocity is roughly proportional to the square root of the ratio of M/A. Scaling reveals that larger cyclists have a greater ratio of mass to frontal area. They therefore descend hills faster as a consequence of purely physical, not physiological, laws. Since the larger cyclist has a greater mass, gravity acts on him or her with a greater force than it does on a smaller cyclist. (Note: A common misconception is to note the equal acceleration of two different sized objects in free fall in a vacuum, and assume that the force of gravity on both is equal. The force on the more massive object is greater, being exactly proportional to mass, which is why the more massive object is accelerated at the same rate as the less massive one.) While the larger cyclist also has a greater absolute frontal area than the smaller cyclist, the difference is not as great as that for their masses. Thus, the larger cyclist will attain a greater s3 before a balance of forces results in terminal velocity.

With lighter cyclists climbing hills faster due to their greater relative VO2max, and heavier cyclists descending faster due to their greater M/A ratio, one might assume that equal performances would occur in races involving equal up and down segments. However, ascents take longer than descents, so a speed advantage to small cyclists on the acsents produces a greater time advantage than large cyclists obtain on the descents. For this reason, smaller cyclists are generally superior competitors on hilly road races.
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#6
This is all very well and good, but on a mountain bike you have to go round corners. Breezer will tell you about his 2CV race car. It was stripped out, not just because he has no friends and so no need for a passenger seat, but to make it lighter. This helped it corner better.
Keep it foolish...
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#7
"lotusandy" Wrote:With lighter cyclists climbing hills faster due For this reason, smaller cyclists are generally superior competitors on hilly road races.

I'm quicker in the cheese straw queue. I'm all elbows
Keep it foolish...
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#8
Fatties are slower..... That’s my excuse anyway
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#9
"Tinc" Wrote:... by it's added acceleration.

[sits back & waits to be corrected]
Here you are: it's should be its.
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#10
On a typical downhill section i would say no, slower acceleration, more mass to decelerate, more mass for the bike to absorb over rocks etc etc.
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