Related
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Zwift FTP and Garmin FTP different value

ManSurfingOnLifeBuoy
over 2 years ago

I did my FTP Ramp Test on Zwift and it is now set at 161.

I synchronize my Zwift data with Garmin and everything looks fine, all but the FTP results.

In Garmin, FTP is set at 2.77W/kg, 88.2 x 2.77 = 244W.

If I would ride, according to Garmin, for an hour at 244W, it would have been a long time that ambulances would have came and brought me to the hospital.

How does Garmin calculate their FTP ?

And why is it different than the Zwift App if Garmin can only transfer the data from Zwift ?

  • 0 over 2 years ago
    ManSurfingOnLifeBuoy said:
    And why is it different than the Zwift App if Garmin can only transfer the data from Zwift ?

    From the document What Is the Functional Threshold Power Feature on My Garmin Device? | Garmin Customer Support

    How Is My FTP Estimate Determined by My Device?
    Garmin devices take your user profile information from the initial setup to estimate your FTP. From there, once you have established a VO2 Max Estimate, that value will be used to determine your FTP Estimate.

    For the most accurate value, you can conduct an FTP test using a paired power meter and heart rate monitor.

    For instructions for performing an FTP test, refer to your owner's manual.

    Why Am I Not Getting an Updated FTP Estimate Reading for My Recorded Activity?
    In a guided FTP test, a new FTP estimate will only be generated if the following conditions are met:

    • Activity must include heart rate data from either a built-in optical heart rate sensor or from a chest strap.
    • 95% of the average power for a 20-minute interval within the ride must be greater than the current FTP setting.
    • The average power for that interval of time must be greater than the previous 20-minute power record.

    Outside of a guided FTP test, a new FTP estimate will only be generated if the following conditions are met:

    • FTP Auto Calculation is enabled (refer to your owner's manual).
    • Activity must include heart rate data from either a built-in optical heart rate sensor or from a chest strap.
    • 95% of the average power for a 20-minute interval within the ride must be greater than the current FTP setting.
    • The average power for that interval of time must be greater than the previous 20-minute power record.

    .

    I do not use Zwift, so cannot tell for sure, but from what is written in the document, I'd tell that FTP is not being imported or updated, unless you record the ride with your Garmin device and meet the above mentioned conditions

  • 0 over 1 year ago

    Zwift is based on 95% of max wattage over a sustained 20 min period. Garmin works on an absolute number based on 1 hour, so it’s likely Zwift will always be higher.