Garmin 500-Does strava use GPS speed or speed-sensor speed?

alihisgreat
alihisgreat Posts: 3,872
edited November 2016 in Road general
Just been checking out my sprint, nothing too serious, just a cheeky stretch of the legs and hit 33-34mph according to the real time value showing on the garmin -> but Strava says I peaked at 28.1mph (compared to 32.8mph for connect)

Doesn't it defeat the purpose of the speed sensor if the Garmin logs the GPS data?

Comments

  • lc1981
    lc1981 Posts: 820
    There's some discussion of this here: http://www.bikeradar.com/forums/viewtopic.php?f=40013&t=12897221.
  • alihisgreat
    alihisgreat Posts: 3,872
    That's talking about the cadence and not the speed though...
  • gloomyandy
    gloomyandy Posts: 520
    The following might be of interest:
    https://strava.zendesk.com/entries/2122 ... s-recently
    https://forums.garmin.com/archive/index ... 28227.html
  • lc1981
    lc1981 Posts: 820
    edited January 2013
    ALIHISGREAT wrote:
    That's talking about the cadence and not the speed though...

    Yes, sorry, I was getting confused with this thread: http://www.bikeradar.com/forums/viewtopic.php?f=40020&t=12897173. The speed from the sensor should take precedence over the GPS-based speed. How long did you sustain the higher speed for? The Garmin has different data recording settings. It can record every second but doesn't default to this. Perhaps that explains it if you were only at this speed for a few seconds?

    Edit: OK, so it's showing up on Garmin Connect so the issue is therefore with Strava.
  • alihisgreat
    alihisgreat Posts: 3,872
    gloomyandy wrote:
    The following might be of interest:
    https://strava.zendesk.com/entries/2122 ... s-recently
    https://forums.garmin.com/archive/index ... 28227.html


    Took a link on the Strava page you provided (thanks!) which took me to this: https://strava.zendesk.com/entries/21278088

    Which says that there is a hierarchy of devices ->

    Hierarchy of Garmin Device inputs when multiple Distance data sources exist:

    What happens if you have a power tap or a GSC-10 Speed/Cadence sensor or both? When the Edge has multiple sources for the same information it uses a predetermine selection process to go with what it considers will be the most accurate source.

    - If you have a Power Tap hub connected to your Gamin, it will take speed readings from the Power Tap hub above all other inputs.
    - If you have a GSC-10 Speed/Cadence sensor, the Garmin will take readings from this output over the GPS-calculated distance.
    - If you have neither, the Garmin will calculate distance based on GPS.

    The key is that the data from either of these sources are seamlessly incorporated into the recorded file, under the distance stream. In some cases, the speed in MPH is documented in the file also, as an extension. Regardless, each Garmin-produced file has a distance stream of data measured in accumulated meters that serves to measure total distance and speed (both max and average).

    So its nice to know Strava is theoretically using the data from my Speed sensor.. but the value still differs on Garmin connect at 32.7mph and on Strava at 28.1mph


    So basically Strava is just for showing off and social aspects, and I need to use Garmin connect if I want to see what actually happened?
  • rsilvers
    rsilvers Posts: 70
    ALIHISGREAT wrote:
    So its nice to know Strava is theoretically using the data from my Speed sensor.. but the value still differs on Garmin connect at 32.7mph and on Strava at 28.1mph

    I think I read that if Strava detects anomalies in the data (too great a difference), it will discard the speed sensor data, and revert to GPS data. This may be an example of that happening. If you do another ride, it should show the same speed.

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