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Forerunner 935 accuracy on a track

bart_vdw
over 6 years ago
Today was the first day I used my Forerunner 935. I immediately tested it in two track races: a 3000m race and an 800m race:

* 3000m race: https://connect.garmin.com/modern/activity/1926043892
* 800m race: https://connect.garmin.com/modern/activity/1926043919

Notice that the distances recorded are not correct:
* 3000m race -> actual recorded distance is 3240m (240m extra, which is an error of 8%)
* 800m race -> actual recorded distance is 880m (80m extra, which is an error of 10%)

I have used the Virtual Partner in these races to set a pace, but because of the larger distances recorded, the pace given was too optimistic (which means I thought I was running at a good pace to break my record, but in reality I wasn't...).

Has anyone experienced errors of these magnitudes on track recordings? Can I do anything about it? Or might there be something wrong with my device?

Thanks for your comments,
Bart
  • 0 over 6 years ago
    Did a workout + a test today:

    workout: https://connect.garmin.com/modern/activity/1960445790
    => We did 8 x 1000 m with 7 x 400 m rest = 10800 m (not always in lane 1, sometimes in lane 2...) but the device recorded 11700 m, which is 900 m more or an error of 8%! That is more than 2 laps too much! (I had the watch on my right wrist, and in the settings it was also set to right wrist)

    test 800m: https://connect.garmin.com/modern/activity/1960445849
    => watch recorded 850 m => an error of 50/800 = 6% (I had the watch on my right wrist and in the settings it was also set to right wrist).

    I would love to see some more tests on a 400 m track, with people running in lane 1 and comparing left and right wrist results... If you switch wrist though, make sure you also change it in your user profile settings on the watch. You never know that matters...
  • 0 over 6 years ago
    Looks like you have shown the wrist setting has no effect in this context.

    realise you want to wear the 935 on your right but as I have said several times, for best results on track then, for me at least, left wrist was the far better choice.
  • 0 over 6 years ago
    Or I could run the track clockwise :)
  • 0 over 6 years ago
    Or I could run the track clockwise :)


    Sounds indeed like a good test! Next time I'll wear on my right wrist, running a clockwise 800m :-)
  • 0 over 4 years ago

    Responding to an old thread here, but I just ran a 5K TT on the track this past weekend, and also had a huge GPS distance error.  I did 12.5 laps on a 440yard track which is 3.125 miles, but my Garmin 235 recorded it as 3.3 miles.  That doesn't seem like a big number, but that's a difference of almost 0.175 which is almost 3/4 of a lap.  When running at a 6:30 pace that's 1min:8s difference, which is huge.

  • 0 over 4 years ago in reply to IBaKiteboarder

    For distance on a track to be reasonably accurate you need a Stryd. GPS just doesn't cut it.

    That said, if you did have the watch on your right wrist, switching to your left will make it better.