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  1. #1
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    Trainer that produces power graphs?

    Physics teacher looking to spend a little bit of the possible leftover end of the year science budget.

    I'm trying to develop a lab whereby students pedal on a bike at different cadences and we measure power, heart rate, speed, etc. - whatever we can, but definitely power. I'd like to be able to save the data in a graph so that we can do some simple analysis. We have the bike and computers already, just need something to do the data collection (and allow us to spin).

    Anyone have any idea what might be a good fit for that task? Not looking to break the bank - a few hundred dollars would fly. 1K+ won't. Your input is appreciated.
    My other bike is a /7.

  2. #2
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    Sounds like a computrainer is what you need - RacerMate.

    However, they are over your budget new although you may be able to find one used or get a special rate because you are using it within a school. You'll be hard pressed to find any new power meter for less than $700 - you could check out StageONE though - they have one that goes in the crank arm. With this route you'd still have to get a trainer to put the bike on though, and then a bike computer capable of reading the Ant+ signal from the power meter.

  3. #3
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    editing away info that i don't think is quite valid.
    Last edited by brassnipples; 01-14-2014 at 09:38 AM.

  4. #4
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    A used PowerTap might fit your needs, it happens I'm trying to sell mine. You could couple it with an ANT+ stick and use GC as stated above or an ANT+ dongle for iPhone/iPad and whatever app suits your needs.
    Powertap - Open Pro rear wheel and accessories - RoadBikeREVIEW.Com

    Another alternative is to use the SportTracks Trainer Power plugin that maps speed to power for many different trainers. It works OK depending on setup and the trainer/tire used as brassnipple stated.
    Check out my SportTracks plugins for some training aid software.

  5. #5
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    The Elite Arion Digital rollers might be what you're looking for. Ant+ 495gbp / $770 USD and available soon:

    Arion digital - Elite /en

    Elite Arion Digital Parabolic Resist Rollers | Buy Online | ChainReactionCycles.com

    You could either output its information straight to Goldencheetah or have something like a Garmin Edge 500 set to record the data before downloading it onto a PC.

    I saw it mentioned on the DC Rainmaker site where he was planning on reviewing it in the next few weeks.

  6. #6
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    Kurt Kinetics publishes a power vs speed function for their Road Machine trainers. So if you can measure speed (with a simple bike computer), you can calculate power.

  7. #7
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    Quote Originally Posted by tbaier View Post
    Physics teacher looking to spend a little bit of the possible leftover end of the year science budget.

    I'm trying to develop a lab whereby students pedal on a bike at different cadences and we measure power, heart rate, speed, etc. - whatever we can, but definitely power. I'd like to be able to save the data in a graph so that we can do some simple analysis. We have the bike and computers already, just need something to do the data collection (and allow us to spin).

    Anyone have any idea what might be a good fit for that task? Not looking to break the bank - a few hundred dollars would fly. 1K+ won't. Your input is appreciated.

    Hi Tbaier,

    I created a device to measure power off a Kinetic trainer and display it and graph it on a laptop. Maybe I can help you. I am at work now, in the evening I'll send you a picture.

  8. #8
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    As a physics and chemistry teacher, I'm interested in this project. I wonder if TrainerRoad would be willing to work with you on this. They already have the ability to do what you are wanting -- get the data, export to the computer or simply have the kids transfer it to their computer.
    If you can be blissfully ignorant to the notion that something is impossible, then you might surprise yourself. -- Andrea138

  9. #9
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    Here's the formula for the Kurt Kinetic conversion from speed to Power.
    Watts= 5.2448 * mph+0.01968*mph^3

    Would seem to be a pretty reasonable measure of relative power even if the absolute values may be a bit off. Somewhere on the web I saw of comparison of this with a powertap and they tracked each other real well.

  10. #10
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    Analyzing potential sources of error is a good classroom exercise in any case. For example, plugging your measured speed into that formula only gives you the steady-state power at that speed.

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