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Incorrect FTP determination

Feddersen
over 3 years ago

Hi

I had a ride where the 830 found a new FTP for me. However it was incorrectly determined. My best 20 minute performance was 285 watt and that calculates into a FTP of 271 which the 830 determined as my new FTP. However in the same ride my hourly performance was 279 watts. Since FTP is the maximum effort within an hour I would assume the 830 would use that value since it was higher but it didn't.

Is there any special reasoning for this or is it an error? In case of an error how do I report it to Garmin?

Best regards Karsten

  • 0 over 3 years ago

    Did your 830 calculate the 0 watts into the average? (System-Data recording - Power Averaging - Zeros included) Can You share (the graph of) this activity somehow?

  • 0 over 3 years ago in reply to Luko79

    Here are the numbers from the ride. They are including the 0-watt periods. All purely Garmin-numbers from the 830 and the Garmin Connect platform and app. 

    This is the 20 min graph

    This is the 60 min gragh:

    The outcome of the ride said FTP = 271. 

    Watt meter are Garmin RS200 pedals.

  • 0 over 3 years ago

    The Garmin generated FTP number is the result of a Firstbeat algorithm.  It doesn't just take the power you have done for a certain amount of time and multiply that by a number to generate FTP.  It relies on HRV data from your heart rate measurements too.

    If you don't think it is right just ignore it and do normal FTP tests to calculate your FTP and put that number in your Garmin.

  • 0 over 3 years ago in reply to Wongataa

      he rode @279w 60mins, so his FTP 279w minimum, but somehow the "firstbeat algorithm" just used the old-fashioned best 20mins watt * 0.95 formula (285/0.95=271w). So something is not good in the algorithm 

    opinion?

  • 0 over 3 years ago in reply to Luko79

    Found this and it looks almost like Garmin is contradicting themselves: https://support.garmin.com/en-US/?faq=i96M1HykRy4LgvA6bORZC9

    Garmin is explaining that FTP is ".. considered to be the highest power level you can maintain for one hour without growing fatigued." - yet they use the 20 minute value to calculate it. 

  • 0 over 3 years ago in reply to Luko79

    Or the Firstbeat algorithm coincedentally calculated a FTP the same as the other method.  That is perfectly possible.

    However the number is generated, if you don't like it ignore it.