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24-10.-2007, 07:59 AM
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#1 |
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Registered User
Join Date: Jul 2007
Posts: 62
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KK trainer power output for additional flywheel??
Hello all. I got a chart from these forums which calculated power for mph on the KK trainer a little while ago.( I believe from wiredued) I have a friend who is going to get an additional flywheel for added resistance. Is there anyone out there who can recalculate the KK numbers for an additional 10-15 lbs of resistance that the flywheel provides? Would it just be a percentage estimation? anybody?? thanks.
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24-10.-2007, 08:03 AM
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#2 |
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Registered User
Join Date: Apr 2005
Location: Kansas City, USA
Posts: 3,691
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Re: KK trainer power output for additional flywheel??
Adding weight to the existing flywheel should not change the resistance curve of the unit.
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24-10.-2007, 08:15 AM
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#3 | |
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Registered User
Join Date: Jul 2007
Posts: 62
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Re: KK trainer power output for additional flywheel??
Quote:
Ok. So the weight is attached to the existing flywheel, huh? I had it wrong there  duhhh...Well, none the less, that is good. No new calculations needed! Great!! Thanks!! |
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24-10.-2007, 08:25 AM
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#4 | |
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Registered User
Join Date: Jul 2007
Posts: 62
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Re: KK trainer power output for additional flywheel??
Quote:
ok. After thinking on this, which may be the problem  I am confused. If you add weight to the flywheel, you need more power to attain the same mph you would achieve without it, right? Shouldn't that change the mph readings and the power output that corresponds with it? |
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24-10.-2007, 08:41 AM
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#5 | |
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Registered User
Join Date: Aug 2004
Posts: 1,173
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Re: KK trainer power output for additional flywheel??
http://www.kurtkinetic.com/faq.php
"The Pro Machine was designed specifically for use with the extra weight of the optional 12 lb. flywheel. Because of the extra weight, it requires a bigger 16mm shaft (versus the 12mm of the Road Machine) and also the Pro Machine’s 16 mm shaft is threaded to accept the attachment bolt to hold the 12 lb. flywheel in place." "It’s the fluid chamber alone that provides the resistance and so the resistance does not change, even with the additional 12 lb. flywheel. The extra weight of the 12 lb. flywheel is only designed to make the ride even smoother and to replicate the outdoor road ride. Because the fluid chamber alone provides the resistance, there is no need to recalibrate the Kinetic PC when using either just the 6 lb. permanent flywheel or the additional 12 lb. flywheel." Formula 5.244820x + .019168x^3 17mph=183.33w 17.1mph=185.53w 17.2mph=187.74w 17.3mph=189.98w 17.4mph=192.23w 17.5mph=194.51w 17.6mph=196.80w 17.7mph=199.12w 17.8mph=201.46w 17.9mph=203.81w 18mph=206.19w 18.1mph=208.59w 18.2mph=211.01w 18.3mph=213.45w 18.4mph=215.91w 18.5mph=218.39w 18.6mph=220.89w 18.7mph=223.42w 18.8mph=225.96w 18.9mph=228.53w 19mph=231.12w 19.1mph=233.73w 19.2mph=236.36w 19.3mph=239.02w 19.4mph=241.70w 19.5mph=244.40w 19.6mph=247.12w 19.7mph=249.86w 19.8mph=252.63w 19.9mph=255.42w 20mph=258.24w 20.1mph=261.07w 20.2mph=263.93w 20.3mph=266.81w 20.4mph=269.72w 20.5mph=272.65w 20.6mph=275.60w 20.7mph=278.58w 20.8mph=281.58w 20.9mph=284.60w 21mph=287.65w 21.1mph=290.72w 21.2mph=293.82w 21.3mph=296.94w 21.4mph=300.09w 21.5mph=303.26w 21.6mph=306.45w 21.7mph=309.67w 21.8mph=312.92w 21.9mph=316.19w 22mph=319.48w 22.1mph=322.80w 22.2mph=326.15w 22.3mph=329.52w 22.4mph=332.92w 22.5mph=336.34w 22.6mph=339.79w 22.7mph=343.26w 22.8mph=346.76w 22.9mph=350.29w 23mph=353.84w 23.1mph=357.42w 23.2mph=361.03w 23.3mph=364.66w 23.4mph=368.32w 23.5mph=372.01w 23.6mph=375.72w 23.7mph=379.46w 23.8mph=383.23w 23.9mph=387.03w 24mph=390.85w 24.1mph=394.70w 24.2mph=398.58w 24.3mph=402.48w 24.4mph=406.42w 24.5mph=410.38w 24.6mph=414.37w 24.7mph=418.39w 24.8mph=422.44w 24.9mph=426.51w 25mph=430.62w 25.1mph=434.75w......Lance Armstrong FTP maybe 25.2mph=438.91w 25.3mph=443.10w 25.4mph=447.32w 25.5mph=451.57w 25.6mph=455.85w 25.7mph=460.16w 25.8mph=464.49w 25.9mph=468.86w 26mph=473.26w Quote:
__________________
Romans 5:10 For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life. http://www.earnharts.com/html/reala...ecific.asp?id=3 Last edited by wiredued : 24-10.-2007 at 08:56 AM. |
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29-10.-2007, 04:30 PM
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#6 | |
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Registered User
Join Date: Mar 2006
Location: Budd Lake NJ
Posts: 187
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Re: KK trainer power output for additional flywheel??
Quote:
Do you have any numbers for the Clydesdale unit. I bought one, but can not even find it on the Kinetic Website. Google only find those for sale. No info. Looks Identical to the standard. I assume the internals have been changed to simulate a heavier rider. |
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29-10.-2007, 10:16 PM
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#7 | |
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Registered User
Join Date: Feb 2007
Location: East Coast
Posts: 127
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Re: KK trainer power output for additional flywheel??
The numbers you list below match the table provided on the Kurt Kinetic website, but don't seem to match the formula. For example, I get 185.84 watts when I use the formula for 17 mph. Which do you suppose is correct?
Quote:
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29-10.-2007, 10:36 PM
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#8 | |
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Registered User
Join Date: Aug 2004
Posts: 1,173
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Re: KK trainer power output for additional flywheel??
I made the same mistake as you just did some one here corrected me a while back it is a typo on the kinetic site considering the number entered into the computer is .01917 which is very close to .019"1"68 not .01968
Quote:
__________________
Romans 5:10 For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life. http://www.earnharts.com/html/reala...ecific.asp?id=3 |
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29-10.-2007, 10:59 PM
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#9 | |
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Registered User
Join Date: Aug 2004
Posts: 1,173
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Re: KK trainer power output for additional flywheel??
Sorry I don't know anything about that unit... BTW what is the flywheel weight on the Clydesdale?
Quote:
__________________
Romans 5:10 For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life. http://www.earnharts.com/html/reala...ecific.asp?id=3 |
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30-10.-2007, 08:31 AM
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#10 | |
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Registered User
Join Date: Mar 2006
Location: Budd Lake NJ
Posts: 187
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Re: KK trainer power output for additional flywheel??
It looks like the same exact size as the standard Road Machine. So barring different materials it is the same.
I like the smaller flywheel cause I have to make my spin smooth. Not the flywheel. I would think the power curve during accelerations and decelerations would be different with different flywheel weights, but same at steady state. So the heavier flywheel might fell more real during sprints and such for a big guy. I am not so concerned about that though. Quote:
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30-10.-2007, 08:45 AM
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#11 | |
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Registered User
Join Date: Oct 2006
Posts: 1,506
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Re: KK trainer power output for additional flywheel??
Quote:
So to answer your questions, the watts vs mph readings from your KK or other trainer won't change with a larger flywheel in ways that you can measure. The larger flywheel will just smooth out the irregularites of your pedal stroke by coasting through the dead spots better. If you could make very fast micro power measurements you'd see it takes additional energy to initially accelerate the larger flywheel but you'd get that energy back by maintaining wheel speed when you coasted saving you the effort of accelerating the system again to make up for the lost speed. In general you won't see these differences during acceleration for reasonably sized flywheels because the moment of inertia is still relatively small and cyclometers and power meters only sample so often and usually average their displays a bit to reduce erratic readings. IOW the additonal moment of inertia is small enough that you still acellerate the trainer fairly fast and the averaging/sampling rate of the cycling computers make it hard to see the micro differences during that period of acceleration. -Dave |
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