We have tried to explain the best way to cycle and we
have used Chris Froome as an example and a flywheel:
18 juil. 2013
Gregory
Bateson wrote an interesting book about: “What every school 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.
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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
The difference between torque and power is that power moves the object; torque is the force apply and it is equal in number
to power when the rpm is 5252:
An engine produces POWER by providing
a ROTATING SHAFT which can exert a given amount of TORQUE on a load at
a given RPM.
Humans pedal at 90 rpm average now a days (by looking
at the Grand Tours), so we are too far from equalizing power and torque. We have different curves related to
torque-power-rpm. Fortunately, there is
an interesting paper written that studies the curve torque-rpm-power in bicycles.
What it shows is that at low rpm too
much force is exerted to move the wheels compared to high cadence low torque at
the same speed. The velocity of the
bicycle is the same; high torque vs low torque by changing cadence. Also, the curve torque-rpm-power is very
different by changing just 20 rpm.
Table 1
Mean pedaling cadence,
cycling velocity, power output and crank inertial load of the cyclists during
experimental condition. Uphill (U) vs. Flat (L)
Cycling condition Pedaling cadence (rpm) Power output (w) Velocity
Crank Inertia (kg/m2)
U60 61.1+-1.9
325+-43 15.0+-0.8 42+-3.7
U80 80.8+-1.6
325+-39 14.8+-0.7 23+-1.6
L80 82.2+-1.6
322+-40 38.3+-1.4 158+-19
L100 99.0+-1.3
325+-35 38.7+-1.5 107+-15
What we see is that the torque does not convert "fully" to
power at low cadence and it is seen in the crank inertia load; we waste energy using that much torque to move something at speed that could be accomplished with less torque. The flywheel plays a role in the equation.
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