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  1. #1
    Life is Short...Ride Hard
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    Garmin Edge 500 accuracy issues

    When on the road, it is spot on. But i have noticed that my millage and speed are off quite a bit at times when on the trail. Where i ride, there is a lot of tree cover.

    Is the garmin edge 500 just not that good for riding under the trees? Any one else having this issue?

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  2. #2
    sheep in FOX clothing
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    Based on the real-time display, or viewing the tracklog after-the-fact?

    If the later, make sure it's set to 1-second recording.

    If the former, you may need to spring for a wheel magnet sensor.

  3. #3
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    Re: Garmin Edge 500 accuracy issues

    Both actually. It gets a slightly more accurate when uploaded to strava.
    But im still off a half mile, sometimes a full mile.
    I have it set to 1 sec. I learned earlier this year that smart recording wasnt that smart at all. Missed switchbacks completely.

    And as far as speed goes, i was much faster than my buddies yesterday, yet my average speed was calculated slower than 2 out of the 3.

    But like i said before, when on the road, it is spot on perfect. So thats why i think its because of the canopy and not getting a great signal. Possible?

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  4. #4
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    Re: Garmin Edge 500 accuracy issues

    Side note, other riders were using garmin 305, garmin 805 & strava app on iphone.
    I had better speed numbers than the phone but less millage.
    The other garmin units, were higher than mine in both categories.

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  5. #5
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    a GPS will always underestimate distance if it's reasonably accurate. This is because the GPS draws straight lines between track points, which cuts curves a little short every time.

    There will be a little bit of variation between devices. Phones and old GPS receivers (~10yrs old) are less accurate, so they might actually overestimate distance due to the presence of one or more bad points.

  6. #6
    sheep in FOX clothing
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    If you are talking about numbers being off on actual Strava segments, that is no one's fault but Strava's, and a well-documented issue they have been aware of for more than a year but apparently have been unable to fix.

    If you're losing mileage over the entire ride, then you may need to add a wheel magnet to get the accuracy that you're after in the trees.

  7. #7
    trail rat
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    It is a road computer, designed for relatively straight modern roads, not twisty singletrack. Twisty trails confuse it's recoding algorithm, since roads to not wind back and forth every few feet. It is the wrong tool for the job of recording trail rides.
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  8. #8
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    Re: Garmin Edge 500 accuracy issues

    Quote Originally Posted by slocaus View Post
    It is a road computer, designed for relatively straight modern roads, not twisty singletrack. Twisty trails confuse it's recoding algorithm, since roads to not wind back and forth every few feet. It is the wrong tool for the job of recording trail rides.
    So what are some good devices for me to consider that would work great in the woods?

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  9. #9
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    705, 800 and I presume 810. Can't get much deeper than the coastal Redwoods in California. However, you can't do 1 second recording on the 705 for more than 4 hours. So I don't recommend it anymore for those who do longer rides. I also recommend running your file through Topofusion for more accurate mileage.

  10. #10
    sheep in FOX clothing
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    Quote Originally Posted by slocaus View Post
    It is a road computer, designed for relatively straight modern roads, not twisty singletrack. Twisty trails confuse it's recoding algorithm, since roads to not wind back and forth every few feet. It is the wrong tool for the job of recording trail rides.
    This is incorrect. The 500 has had a fixed 1-second recording function since a 2011 firmware upgrade. I've recorded a 10-hour ride in this mode without running out of track points.

    Personally, I've never seen any sort of track accuracy difference between the 500 and the 800 when they are recording on the same interval.

  11. #11
    trail rat
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    Quote Originally Posted by ghettocruiser View Post
    This is incorrect. The 500 has had a fixed 1-second recording function since a 2011 firmware upgrade. I've recorded a 10-hour ride in this mode without running out of track points.

    Personally, I've never seen any sort of track accuracy difference between the 500 and the 800 when they are recording on the same interval.
    I know that they updated firmware with one second recording, but can you give me a link that shows they changed the recording algorithm?

    No where I have seen Garmin mention or advertise the 500 as anything but a road bike designed GPS; all the press releases when it was introduced (at the Tour of Australia) and tutorials and info on their website and blog suggest it as a road computer. Garmin regularly posts tracks from the 500 used by pros in races, but I have yet to see them post any tracks from off road races, nor do they even sponsor off road racers. Garmin Athletes
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  12. #12
    sheep in FOX clothing
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    Quote Originally Posted by slocaus View Post
    I know that they updated firmware with one second recording, but can you give me a link that shows they changed the recording algorithm?
    I'm not sure I understand your request. The recorded tracklog in this mode is one trackpoint every second with a straight line between them. So wouldn't the recording algorithm be T=1 second? What other variables would there be in the track interval to calculate?

  13. #13
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    I had the same problem with my 500. I had to set it for 1 second intervals and get a wheel sensor. now its spot on. the trees are messing it up.

  14. #14
    Shuttles R 4 Pussies
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    Quote Originally Posted by LvilleFan View Post
    I have it set to 1 sec. I learned earlier this year that smart recording wasnt that smart at all. Missed switchbacks completely.
    How are you able to set data sampling to 1 sec? I have a 3 month old Edge 500 with current firmware, and it doesn't say anything in the manual about being able to change sampling rate. All it says is that "The Edge uses smart recording" with no mention of a setting to change it.

    I'd love to be able to try to change it and see if it solves the problem I have of my Edge constantly pausing and restarting itself during rides (maybe losing its satellite fix?). Sometimes this happens as often as five second intervals. My riding buddy, who bought his Edge 500 the same time as I did, doesn't have this problem. Both of us are using the GPS for speed/distance rather than wheel sensors. Originally I had mine tied to my wheel sensor, but on a Garmin forum it said this can sometimes cause the unit to pause and restart, so I disabled it but the problem still occurs.
    Screw the shuttle, I'm riding to the top. You're all worthless and weak!!!

  15. #15
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    mine never stops or pauses so that's a different problem.

    to change recording intervals

    menu
    settings
    bike settings
    data rec
    data recording
    every second

  16. #16
    Shuttles R 4 Pussies
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    Quote Originally Posted by JonathonFLA View Post
    mine never stops or pauses so that's a different problem.

    to change recording intervals

    menu
    settings
    bike settings
    data rec
    data recording
    every second
    Great. Thanks for the info. That's something they should include in the user's manual.

    I'll give it a shot and see if anything improves.
    Screw the shuttle, I'm riding to the top. You're all worthless and weak!!!

  17. #17
    trail rat
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    Quote Originally Posted by BrentP View Post
    Great. Thanks for the info. That's something they should include in the user's manual.

    I'll give it a shot and see if anything improves.
    The user manual was printed before that option was added via a firmware update. Garmin usually has updated PDF manuals online, and the firmware changelogs will alert you to changes too.
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  18. #18
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    This problem was main reason I did not get one couple years ago. People would lose info in woods. I am sure it is much better now, but, I already have the cateye wheel sensor and it is fine for me. I mean as long as I compare myself to myself, I can see good or bad. Not strava orientated as I know I am slow. Little more conditioning and go from there.

  19. #19
    Shuttles R 4 Pussies
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    Unfortunately I won't be able to try the 1 sec setting until next week, as I'm heading off to Los Angeles in an hour and won't be back until Tuesday. At the very least, I hope it helps prevent the "drift" of my GPS, which Strava support explained to me was the cause of some sections of my rides periodically not showing up in Strava after uploading.

    My auto-pause and restart problem occurs both when I'm in the woods and on the road, with nothing to block the signal. It sounds like I might need to follow up directly with Garmin.
    Screw the shuttle, I'm riding to the top. You're all worthless and weak!!!

  20. #20
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    Re: Garmin Edge 500 accuracy issues

    My 800 was doing the auto stop/start thing too, drove me nuts. Went to garmin, got the pdf and all is good. Turned pause to when i stop,beeps off,1 sec recording.
    Next, figure out the basemap thing!

  21. #21
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    I can't comment on the start/stop, but I can say I've been very disappointed in the 500's accuracy. It just can't handle quick transitions in direction. I had a Forerunner 305 prior to this and while the traces were noisier, they were at least accurate. The 500 will say I keep going straight for 50-100 yards even though I've turned. It will then maintain that 50-100 yard offset for over a mile before finally snapping back into position. This happens pretty much every ride and makes Strava a useless endeavor. It's especially obvious on rides where I've taken the road to/from where I ride and it shows me travelling through buildings for the entire return trip. I'm pretty disappointed overall.

  22. #22
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    what settings do you use on your Edge 500? specifically, recording interval.

  23. #23
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    I use "Every Second" recording. I also know I'm not the only one since I've started to look for it in other's traces on Strava. Most of the 500's I've come across display the issue if used in switchbacks that allow you to carry any sort of speed or on road sections with quick corners.

  24. #24
    sheep in FOX clothing
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    Strange. I have positional drift and a "snap-back" maybe once a month, riding every day, and usually less than 10 meters or so. I think it's from a loss of reception, not a logging interval issue. Are you riding with limited skyview (mountains or buildings, trees should be okay)?


    Still haven't seen any difference at all in the 500 and the 800 tracklogs from my rides. He's a tight trail in dense vegetation from the 500 yesterday with 1-sec recording and a wheel magnet.

    Mountain Bike Ride Profile | N.Don&Motown Greenery w/Nick near Toronto | Times and Records | Strava

    (if you're not logged into Strava you'll need to manually zoom in on the SE part of the ride, the rest is road riding)

    The tracklog does incorrectly cross over itself twice if you zoom way in, (non-terrain map mode) but the trail is so close to itself there they put in logs to keep people from making a wrong-tern shortcut.

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