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Watch calculates wrong running distance

Chris
over 2 years ago

Hey there!

I just figured out that my 955 calculates the wrong running distance. On my standard short route my 935 gave me a distance between 6.07 km and 6.09km. This is fairly in line with the distance I calculated using the gmap pedometer (6.23 km). Today as I took the 955 on this route for the first time (second run overall) it gave me 6.94km(!) in Multiband mode. When I compare the routes on the map the tracking is spot on and better than the 935, but the distance is just not right! It seems that it constantly predicts the distance short of about 15%, which accumulated to an overall too long distance for the specific route.

Any Idea what is going on here? Again the route on the map is perfect.

  • 0 over 2 years ago

    I'm not sure that two activities counts as "constantly".  It's possible that the 955 hasn't picked up GPS quickly enough so it might be an idea to make sure that GPS is active before actually starting an activity.

    I've just compared a 5k run I made with my 955 and one I made with my old 945 and they're both exactly the same in terms of GPS trace and distance reported.

    A wonky GPS is the prime suspect for mis-reported distances, I feel.

  • 0 over 2 years ago in reply to Spiderpig

    Thanks for checking!

    With "constantly" I mean it calculates 1km after in reality less than 900m have passed, and it does that for every km. So its not off at some point. Run was started after GPS was locked in, so start and endpoint are perfect. Again, the trace on the map is very nice, so the position is determinded perfectly. Just the distance between them seemed to be calculated wrongly. So exact same trace between 935 and 955 but one says 6.1 and the other 6.9 km. Thats actually a hughe deal for me because it renders the watch useless for any further training.

    It seem I am the only one with this problem. I will try to reset the watch and try again. If it persist I will send it to Garmin.

  • 0 over 2 years ago

    My 955 usually shows I have run more miles than my other watches. I’ve been running with it for about a month and consistently is showing more than both my 945 lte and my old 935 on the same runs. In open areas for example last night my 955 showed 6.15 miles and my 945lte showed 6.01. On a trail run it’s even more off for example my 955 has shown 9.5 miles when my 945lte showed 9.0 . I’m not sure what watch is accurate but I’ve had 910,920,930,945lte and 955 and most have been very close in distance like no more than a few hundredths off on a run. It’s starting to get annoying. 

  • 0 over 2 years ago

    I'm seeing similar, on my 6km route its coming in at 6.25... about 10s/km out compared to stryd, which is alot. Also my chest garmin run, is about 6 or 7 beats lower than with my previous 645M.  

  • 0 over 2 years ago in reply to masoncc

    that's odd. my 955 has been spot on (within 0.01-0.02mi) for 6-8mi runs compared to my 945LTE and 935  (ie, runs that i have done many times). moreover, the 955 gives me much better instantaneous pace and absolute position of where i ran (side of road/trail) than the 945LTE or 935 ever did.

    (i'm using All Satellites while my 945LTE and 935 were with GPS "only")

  • 0 over 2 years ago

    Compared to 945 my 955 calculated distance properly even without full GPS fix (during that day when all had problem), so that's weird.

  • 0 over 2 years ago

    I suspect older watches were under-reading the distance due to their less accurate GPS. With my previous watch I would consistently have to run about 5-10% longer to cover the distance I'd calculated on a map tool like plotaroute.com.

    I've switched to per-second logging rather than smart logging.

  • 0 over 2 years ago

    I’m seeing the same, since moving from 945 to 955 solar parkruns are all coming in at around 5.14km ish as apposed to the usual <5km

  • 0 over 2 years ago in reply to LeonRoss

    Yes, my local parkrun is reading "long" with the 955 compared with the vivoactive3 that usually read it up to 600m short.

    I blamed that on extensive tree cover and many closely spaced right angle bends in the course, multiplied over the four laps.

    I'll probably be doing a beach out-and-back parkrun next weekend, which the va3 has always recorded as 5km (±10m). Let's see what the 955 makes of it.

  • 0 over 2 years ago

    Any updates with this?

    Have a friend who recently purchased a 955 and they are consistently recording long distances. He is using multiband mode.

    He exported a recent 5k run which recorded as 5.11km and calculated distance from the GPS points recorded and it was 5.03km. This seems to indicate that the GPS trace was fine, just the watch has added distance somewhere.

    He has switch to GPS only mode and will run the course again, so will be interesting to see if it is still long.