Initial PowerTap settings

Discussion in 'Power Training' started by MikeMuk, Aug 26, 2006.

  1. Alex Simmons

    Alex Simmons Member

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    AFAIK, it should match - always does with me. Is your PT CPU sampling rate set at 1 sec (actually 1.26 secs) or at a longer sample rate like 2 or 5? I'm not sure if that would make a difference - but what I do know is that, say you have 5 sec sampling - it only records the data point every 5 secs (discarding the others) and not an average of last 5 secs. So maybe (and I'm only guessing) the peak occured during the non recorded data points but it still updated the Max Watts reading in the CPU.

     


  2. Bike N Ski

    Bike N Ski New Member

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    Alex, it was set to 2. I've changed it to 1 and I'll check it on the next ride. Thanks for the suggestion - it makes sense.
     
  3. Alex Simmons

    Alex Simmons Member

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    Have another crack at it and let us know.
     
  4. rayhuang

    rayhuang New Member

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    Sorry for digging up this old thread, but did you guys figure this out? Mine was set at 5 for two months and I too have experienced the same sort of things where my peak watts on the computer does not correlate with what i see in Cycling peaks or on Power Agent. Also-at times I dont see on the graph what I know I did on the ride. Of course this applies mostly to short intensity stuff (under 1 minute efforts and max power).

    Thanks in advance,
    Ray
     
  5. Alex Simmons

    Alex Simmons Member

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    What was set at 5? The CPU rolling average or the frequency of data sample capture?

    If you set it to capture data every 5 sec, it will discard all other data points in between, just recording every 4th one (at 1.26sec per data point). So if your power peak happened on a data point that isn't stored, that's why the difference.

    The CPU will still update the max power number on the CPU display no matter if that data point is stored for later download or not (since all it needs to know is if any instantaneous data point is higher than current max, and if so then update the max value for the CPU display).
     
  6. rayhuang

    rayhuang New Member

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    Frequency of data capture. I set it to 2 for the next ride.

    Thanks Alex,
    Ray
     
  7. sugaken

    sugaken New Member

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    Why? Why not set it to 1? Is there any particular reason you have to set it to >1?

    Even if you change it from 5 to 2, there is still 50% chance for your download data to miss the maximum power you see on the computer.

    Ken
     
  8. rayhuang

    rayhuang New Member

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    Good point-why didnt I set it to 1?!?!?!? My last download seemed to show more subtle variations in power so going from 5 to 2 seemed ot help-though I didnt do any short interval work.
     
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