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  1. #1
    Just ride :-D rjtokyo's Avatar
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    Calculating Power Output on a Trainer

    Is there a way to calculate, or even approximate power output on a stationary trainer, like maybe a Cyclops Fluid 2, without a power meter? It seems that since you don't have any variables of rider weight, wind resistance, road slope, rolling resistance, etc., it may be possible to do based solely on a specific trainer's resistance and the gear ratio being used. On a secondary note, is there anyone in the BF community that has a PowerTap (or equivalent power meter) and say a Cyclops Fluid 2 that would be willing to measure power outputs on the trainer in different gear ratios and post the results?

    I would love to get a PowerTap SL, but it's going to take a while before there's enough $ saved up for it. Thanks!

    - RJ

  2. #2
    Used to be a climber.. GuitarWizard's Avatar
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    If you look on the CycleOps site, I believe there is a chart that will give you approx. watts for a given cadence/gear ratio....

    *EDIT* Nevermind, it's on this site:

    Click me, click me
    Last edited by GuitarWizard; 02-15-06 at 06:46 PM.
    1999 Trek 2500 - hit by a car on it in May, 2011 and currently bikeless

  3. #3
    Just ride :-D rjtokyo's Avatar
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    Quote Originally Posted by GuitarWizard
    If you look on the CycleOps site, I believe there is a chart that will give you approx. watts for a given cadence/gear ratio....

    *EDIT* Nevermind, it's on this site:

    Click me, click me
    Perfect! Thanks GuitarWizard! Just what I was looking for. I'm more and more convinced that training by Power Zones is more effective than with HR.

    Cheers! - RJ

  4. #4
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    I don't understand this chart. The flywheel of the trainer is turned by your rear wheel. Your rear wheel turns at a speed based on cadence and gearing. Turning a 53x12 at a cadence of 60 turns the flywheel at the same speed roughly as turning a 39x15 at a cadence of 100. But the wattage charts shows 700W vs. 500W.

    What am I missing?

  5. #5
    Videre non videri
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    53x12 at 60 gives about 540 W on the chart.
    39x15 at 100 gives about 520 W on the chart.

    What's the problem?

  6. #6
    Realist Greg180's Avatar
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    The link takes you to the Branford bike site...Where in that site is the chart?

  7. #7
    Senior Member huytheskigod's Avatar
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    Hate to drag up an old thread but I would like to have this chart but as the previous poster stated, the link no longers points to the correct data. If anyone knows where to find similar data, it would be very useful.

  8. #8
    Just ride :-D rjtokyo's Avatar
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    Quote Originally Posted by huytheskigod
    Hate to drag up an old thread but I would like to have this chart but as the previous poster stated, the link no longers points to the correct data. If anyone knows where to find similar data, it would be very useful.
    Hey huy-

    Yeah unfortunately that chart seems to have been removed. A while back I used the data from it to make up a chart of wattage output for various gear ratios and I can dig it up and post it here later. Right now I'm heading off to catch a plane for Okinawa to participate in this weekend's two-day Tour d' Okinawa, a 320km ride encirling the island . Will try to post the chart after that.

    Cheers! - RJ

  9. #9
    Senior Member huytheskigod's Avatar
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    Quote Originally Posted by rjtokyo
    Hey huy-

    Yeah unfortunately that chart seems to have been removed. A while back I used the data from it to make up a chart of wattage output for various gear ratios and I can dig it up and post it here later. Right now I'm heading off to catch a plane for Okinawa to participate in this weekend's two-day Tour d' Okinawa, a 320km ride encirling the island . Will try to post the chart after that.

    Cheers! - RJ
    Thanks much! Have fun with the tour as well.

  10. #10
    Senior Member zimbo's Avatar
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    On the CycleOps Fluid2, the power curve depends on the kind of rear tire you are using and how tightly you clamp down on it. You also need to let the unit warm up for 10-15 minutes first.

    I have a PowerTap and here are my own anecdotal measurements with the CycleOps Fluid 2. I'm using a Michelin Carbon tire and I always tighten it down to spec (which for the Fluid2 is 2-and-a-half turns after the clamp touches the tire).

    14 mph = 130 watts
    15 mph = 145 watts
    16 mph = 160 watts
    17 mph = 185 watts
    18 mph = 210 watts
    19 mph = 235 watts
    20 mph = 265 watts
    21 mph = 295 watts
    28 mph = 600 watts
    30 mph = 700 watts

    These are rough ballpark estimates and, again, these are based on tightening the clamp 2.5 full turns from the tire-touch point on Michelin Carbon tires.

    --Steve

  11. #11
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    has anyone done this for a mag850 at the 7 resistance levels??

    has anyone done this for a mag850 at the 7 resistance levels??

    Quote Originally Posted by zimbo View Post
    On the CycleOps Fluid2, the power curve depends on the kind of rear tire you are using and how tightly you clamp down on it. You also need to let the unit warm up for 10-15 minutes first.

    I have a PowerTap and here are my own anecdotal measurements with the CycleOps Fluid 2. I'm using a Michelin Carbon tire and I always tighten it down to spec (which for the Fluid2 is 2-and-a-half turns after the clamp touches the tire).

    14 mph = 130 watts
    15 mph = 145 watts
    16 mph = 160 watts
    17 mph = 185 watts
    18 mph = 210 watts
    19 mph = 235 watts
    20 mph = 265 watts
    21 mph = 295 watts
    28 mph = 600 watts
    30 mph = 700 watts

    These are rough ballpark estimates and, again, these are based on tightening the clamp 2.5 full turns from the tire-touch point on Michelin Carbon tires.

    --Steve
    Joseph Vella

  12. #12
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    I know this is an old thread but here is a working Archive of that branfordbike chart showing watts using a CycleOps Fluid 2 Trainer.

    Any other charts like this? Please post them. Also is their any software or hardware to tap real or even approximate wattage off of a CycleOps fluid 2 Trainer? If not I might put something together.

    http://web.archive.org/web/200508291...r/tr1biga.html

  13. #13
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