Gregory bateson
wrote an interesting book about: “What
everyschool child should know.” He even spoke about education:
''Science, like
art, religion, commerce, and even sleep, is based on presuppositions.’’... ''I have encountered a very strange
gap in their thinking-- (referring to American Students from college freshmen
to psychiatric residents, among humanists as well as scientists) that springs
from a lack of certain tools
of thoughts. Specifically is the lack of knowledge of the presuppositions not
only of science but also everyday life.'' (Mind and Nature, 25).
I found a very interesting conversation
between bikers that illustrates what Bateson mentions and IT is the subject we
should deal with regarding Froome at the Tour de France. ANY
WHEEL HAS A FLYING WHEEL EFFECT:
Flywheel Weight Dyno Chart?
Started by user:4 , Mar 17 2013 05:02 AM
11 replies to this topic
user:4
Posted 17 March 2013 - 05:02 AM
I have been looking for a dyno chart of bikes with and without flywheel
weights installed... Bout to buy one and Im just curious what the power curve
looks like on paper
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- Bolon Yokte K uh
Posted 17
March 2013 - 06:50 AM
- William1
Posted 17
March 2013 - 07:08 AM
Yup. A flywheel only smooths out power delivery.
- Krannie
Posted 17
March 2013 - 09:44 AM
...but it DOES change HP rise time (the time it takes to get to peak
HP).
You might be confusing HP with Acceleration.
You might be confusing HP with Acceleration.
- slomojo
Posted 17
March 2013 - 04:28 PM
Krannie, on 17 March 2013 - 09:44 AM, said:
...but it DOES change HP rise time (the time it takes to get to peak
HP).
You might be confusing HP with Acceleration.
You might be confusing HP with Acceleration.
Most people equate a fast reving engine with a more powerful engine.
A FWW will not change how much power is made at a specific RPM,( the 2 axis on a dyno graph)it only slows slightly how fast an engine reaches a specific RPM from an idle,it also slows how fast it will idle back down after the throttle is closed.
Just because an engine revs faster does not mean the power is transfered to the ground faster, often because of limited traction,vehicle acceleration is slower.
I run lots of extra weight on my CR and it hooks up better in most conditions.
If you are interested in a flywheel weight try one, its as easy to take off as it is to install,and relatively cheep.
Edited by slomojo, 17 March 2013 - 04:30 PM.
- user:4
Posted 18
March 2013 - 04:38 AM
I know I know I know, I have done extensive research on FWW, I dont
expect to see a power gain, but rather the power curve over RPM. I would guess
that without the FWW, the dyno chart would look a bit steeper in the way the
power comes in over RPM. But with the FWW, would you be able to see the cure
change as how the power is delivered?
something like this but real haha
obviously this is not to scale...
something like this but real haha
obviously this is not to scale...
Edited by user:4, 18 March 2013 - 04:39 AM.
- user:4
Posted 18
March 2013 - 04:44 AM
slomojo, on 17 March 2013 - 04:28 PM, said:
Most people equate a fast reving engine with a more powerful engine.
A FWW will not change how much power is made at a specific RPM,( the 2 axis on a dyno graph)it only slows slightly how fast an engine reaches a specific RPM from an idle,it also slows how fast it will idle back down after the throttle is closed.
Just because an engine revs faster does not mean the power is transfered to the ground faster, often because of limited traction,vehicle acceleration is slower.
I run lots of extra weight on my CR and it hooks up better in most conditions.
If you are interested in a flywheel weight try one, its as easy to take off as it is to install,and relatively cheep.
A FWW will not change how much power is made at a specific RPM,( the 2 axis on a dyno graph)it only slows slightly how fast an engine reaches a specific RPM from an idle,it also slows how fast it will idle back down after the throttle is closed.
Just because an engine revs faster does not mean the power is transfered to the ground faster, often because of limited traction,vehicle acceleration is slower.
I run lots of extra weight on my CR and it hooks up better in most conditions.
If you are interested in a flywheel weight try one, its as easy to take off as it is to install,and relatively cheep.
oh im defiantly getting one. the idea makes perfect sense to me and im sure it will compliment my riding style. After a year or so of hearing from people about why I dont need one, I did the research and realized how much benefit they actually have. certainly characteristics I want my bike to have. cant wait to ride! I realized alot of people also dont know what it really does so the just act like its to "slow you down" haha, yeah, thats it
- CBus660R
Posted 18
March 2013 - 05:07 AM
user:4, on 18 March 2013 - 04:38 AM, said:
I know I know I know, I have done extensive research on FWW, I dont
expect to see a power gain, but rather the power curve over RPM. I would guess
that without the FWW, the dyno chart would look a bit steeper in the way the
power comes in over RPM. But with the FWW, would you be able to see the cure
change as how the power is delivered?
something like this but real haha
obviously this is not to scale...
something like this but real haha
obviously this is not to scale...
A flywheel weight will not change the power curve like that. It doesn't move/change the horsepower and torque output relative to RPM. If you graphed it relative to time, then the FWW will soften the curve. That's why people run them, to lessen the hit and give the tire a better chance to maintain traction.
- user:4
Posted 18
March 2013 - 05:34 AM
CBus660R, on 18 March 2013 - 05:07 AM, said:
A flywheel weight will not change the power curve like
that. It doesn't move/change the horsepower and torque output relative to
RPM. If you graphed it relative to time, then the FWW will soften
the curve. That's why people run them, to lessen the hit and give
the tire a better chance to maintain traction.
your'e right. like Krannie said, I was confusing HP with acceleration.
It wouldn't show any difference on a dyno, but riding the bike would be a
noticeable difference because of the amount of time for the acceleration of
your rear wheel.
Edited by user:4, 18 March 2013 - 05:34 AM.
- Bolon Yokte K uh
Posted 18
March 2013 - 06:11 AM
Wait, that's not a real dyno printout?
- Krannie
Posted 18
March 2013 - 06:18 AM
Bolon Yokte K uh, on 18 March 2013 - 06:11 AM, said:
Wait, that's not a real dyno printout?
It's the new Fischer-Price Dyno, from K-Tel.
- kan3
Posted 18
March 2013 - 06:32 AM
Course it's real
We have a very good advertisement done by
ZeroCx, which demonstrate what I want to clarify:
Froome uses the fly
wheel effect that is present in all the components while pedaling: chain rings,
cassette as well as wheels and hubs, when he is pedaling at a high cadence he
takes advantage of this.
To accelerate requires
fewer watts when using high cadence as well as the effect mentioned above. We have mentioned the physiological
advantages in the previous post:
Cycling training: research
shows cyclists should aim for fast pedalling rates on both flat and inclined
routes
Why pedalling fast is more efficient for the cyclist
Elsewhere we have explained that cyclists are usually more efficient on
both hills and flat terrain when they pedal quickly (at about 80-85 rpm) rather
than at slower cadences. Now, a newly published paper suggests that the greater
efficiency may be related to the rapid rate at which glycogen is depleted in fast-twitch
muscle fibres during slow, high-force pedalling.
To determine the actual effects of slow and fast pedalling on leg muscle
cells, scientists at the University of Wisconsin and the University of Wyoming
recently asked eight experienced cyclists to cycle at an intensity of 85% VO2max for 30 minutes under two
different conditions. In one case, the cyclists pedalled at 50 rpm while using
a high gear. In the second case, the athletes pedalled in a low gear at 100
rpm. They were travelling at identical speeds in the two instances, so the
athletes’ leg-muscle contractions were quite forceful at 50 rpm and moderate –
but more frequent – at 100 rpm. As it turned out, the athletes’ oxygen
consumption rates were nearly identical in the two cases, and heart and
breathing rates, total rate of power production, and blood lactate levels were also similar.
However, the athletes broke down the carbohydrate in their muscles at a
greater rate when the 50 rpm strategy was used, while the 100 rpm cadence
produced a greater reliance on fat. The greater glycogen depletion at 50 rpm
occurred only in fast-twitch muscle cells. Slow-twitch cells lost comparable
amounts of glycogen at 50 and 100 rpm, but fast-twitch cells lost almost 50% of
their glycogen at 50 rpm and only 33% at 100 rpm, even though the exercise
bouts lasted for 30 minutes in each case. This rapid loss of carbohydrate in
the fast-twitch cells during slow, high-force pedalling probably explains why
slow pedalling is less efficient than faster cadences of 80-85 rpm. Basically,
as the fast fibres quickly deplete their glycogen during slow, high-strength
pedalling, their contractions become less forceful, so more muscle cells must
be activated to maintain a particular speed. This activation of a larger number
of muscle cells then leads to higher oxygen consumption rates and reduced
economy.
Admittedly, this scenario – in which slow pedalling preferentially pulls
the glycogen out of fast-twitch muscle cells – may sound a little odd to you!
Fortunately, the paradox isn’t really too troubling; after all, slow pedalling
rates are linked with high gears and elevated muscle forces, while fast
cadences are associated with low gears and easy muscle contractions. Since
fast-twitch fibres are more powerful than slow-twitch cells, the fast twitchers
swing into action at slow cadences, when high muscular forces are required to
move the bike along rapidly.
On the other hand, ‘fast’ pedalling rates of 80-100 rpm are not too hot
for the slow-twitch cells to handle. Slow-twitch cells can contract 80-100
times per minute and can easily cope with the forces required to pedal in low
gear. Another possible paradox in the Wisconsin-Wyoming research was that fast
pedalling led to greater fat oxidation, even though maximal fat burning is
usually linked with slow-paced efforts. Basically, the higher fat degradation
at 100 rpm occurred because the slow-twitch cells handled the fast-paced,
low-force contractions. Slow-twitch fibres are much better fat burners than
their fast-twitch brethren!
Fortunately, there’s a bottom line to all this: during training and
competition, cyclists should attempt to use fast pedalling rates of 80-85 rpm,
both on the flat and on inclines. Compared to slower cadences, the higher
pedalling speeds are more economical and burn more fat during exercise.
Ultimately, the high pedalling rates also preserve greater amounts of glycogen
in fast-twitch muscle fibres, leading to more explosive ‘kicks’ to the finish
line in the closing moments of races.
(‘The Effect of Pedalling Frequency on Glycogen-Depletion Rates in Type
I and Type II Quadriceps Muscles during Submaximal Cycling Exercise’, European
Journal of Applied Physiology, vol. 65, pp. 360-364, 1992)
We have shown the following numbers that belong to ironman competitors. The one that weights more produces less power and goes faster by pedaling at a high cadence.
