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  1. #1
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    Lezyne Power GPS Dropping Segments

    I've been using a Lezyne Power GPS for the past two months or so and I have noticed that it drops or misses segments on Strava regularly and consistently. At first I thought it was just GPS drift on a particular ride, but after some regular use, it drops the same segments every time regardless of conditions, tree cover, etc. My iPhone and others' Garmins do not seem to do this. I have used it with both GPS and GPS+Glonass with the same issue. I'm at the point where I'm tempted to buy a Garmin, but then I read about data losses and it makes wonder if I should even worry about Strava segments at all and just stick with the Lezyne. Anyone have any ideas as to why this happens with the Lezyne and not other devices? Do they use different satellites? Is it potentially more accurate than the others and therefore showing slightly different start points that do not match the older data upon which the segments are based? I do not see any way to adjust the data collection frequency with the Lezyne either. Any thoughts are appreciated.

  2. #2
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    jaml,
    Sorry I won't be able to help specifically-I use a Super GPS but I do not use Strava. But I do have a question for you. When you sync your data to GPS Root does all the ride data show including the missing data that does not show in Strava? My suggestion would be to contact Lezyne support with this issue but be patient sometimes they are very quick to respond other times multiple emails may need to be sent. Would like to hear if there is a solution.

  3. #3
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    What you could do is open up one of the original .fit files from the Lezyne Power GPS, in order to have a look the raw data that is being recorded. That could give a clue as to what is happening. It would let you see what the recording rate is and if there are any GPS dropouts or other issues visible.

    The Leyne Power GPS saves rides as .fit files in its "activities" folder. You can plug it into a computer via USB and copy the files out.

    The trial version of Fit File Repair Tool should be able to open them, as you only need to look at the file.

    http://fitfilerepairtool.info/

    .

  4. #4
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    Based on the information given, there's really nothing anyone can say for sure.

    What do your ride files look like overlaid onto maps? Where I live, most of the trails appear on the basemaps Strava is using now, and they look to be pretty accurately represented. So I can see how accurate my recorded GPS file was based on how well it lines up with the trails as drawn on Strava's basemap.

    It's possible that the segments may be made based on inaccurate data, but IME, that's less important than YOUR GPS data.

    It's possible that the Lezyne is doing some data filtering that Strava doesn't like. It's possible you have dropouts. It's possible you've got a single stray recorded point that throws things off. That would be the Lezyne not doing ENOUGH filtering/processing.

    Lots of stuff is possible. Look at the file on a map. Look at the original file.

    Post a link to the Strava activity here, even.

  5. #5
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    Quote Originally Posted by Harold View Post
    Post a link to the Strava activity here, even.
    If it was a group ride you can do Strava flyby, and then look on the map to see how the GPS tracks of different riders line up.

    With my old Garmin Edge 500 for example you could see how its recorded track would be way off route, compared to other people's recorded tracks, in certain places.

  6. #6
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    Quote Originally Posted by WR304 View Post
    If it was a group ride you can do Strava flyby, and then look on the map to see how the GPS tracks of different riders line up.

    With my old Garmin Edge 500 for example you could see how its recorded track would be way off route, compared to other people's recorded tracks, in certain places.
    Yep, that can help, too.

  7. #7
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    Looking at Strava more closely, it does look like the GPS is really off in many places. It definitely deviates from trails that appear on the base maps. When I look at the flyby, the guy I was with has a much more accurate track. He was using a Garmin and it nearly matches the visible trails on the Strava maps. Mine is off at the beginning of the dropped segments enough apparently that they are not documented. Bummer. I really like the Lezyne otherwise. I do not think there is any way to manually change the sampling rate or accuracy. I'll contact Lezyne, but I would imagine this would require a firmware update. So, if you guys were looking at a new GPS, would you go for the Egde 520 or the 500. There are deals to be had on the 500. Or something else entirely?

  8. #8
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    Quote Originally Posted by jmal View Post
    Looking at Strava more closely, it does look like the GPS is really off in many places. It definitely deviates from trails that appear on the base maps. When I look at the flyby, the guy I was with has a much more accurate track. He was using a Garmin and it nearly matches the visible trails on the Strava maps. Mine is off at the beginning of the dropped segments enough apparently that they are not documented. Bummer. I really like the Lezyne otherwise. I do not think there is any way to manually change the sampling rate or accuracy. I'll contact Lezyne, but I would imagine this would require a firmware update. So, if you guys were looking at a new GPS, would you go for the Egde 520 or the 500. There are deals to be had on the 500. Or something else entirely?
    Post up the Strava activity.

    I honestly can't get excited about any of Garmin's more recent stuff. Lots of doo-dads and bells & whistles that I just don't care about.

    I am using a Bryton Rider 310 that I've been mostly happy with. Major drawback to it is that it doesn't offer any navigation capability whatsoever. It simply records. Though it does record pretty well, IME. The only times I've really managed to throw it off have been when I rode underneath a 4 story parking structure. It's been a little off riding through urban canyon territory, too...but better than some older GPSes. Those situations are a real challenge for any GPS. It does not utilize GLONASS, though. From a pure accuracy standpoint, friends who have ridden under the same parking structure actually get fairly accurate tracks with the Garmin Edge 1000. The battery life on that one is just too terrible for me to want to spend my money on it, though.

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  10. #10
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    Your rides don't match.

  11. #11
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    Quote Originally Posted by richde View Post
    Your rides don't match.
    We met on the trail and then rode together for a little bit. The segment, The Juicy Deuce, is missing from mine but shows on the other rider's ride. About 4.3 miles in.

  12. #12
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    Quote Originally Posted by Harold View Post
    Post up the Strava activity.

    I honestly can't get excited about any of Garmin's more recent stuff. Lots of doo-dads and bells & whistles that I just don't care about.

    I am using a Bryton Rider 310 that I've been mostly happy with. Major drawback to it is that it doesn't offer any navigation capability whatsoever. It simply records. Though it does record pretty well, IME. The only times I've really managed to throw it off have been when I rode underneath a 4 story parking structure. It's been a little off riding through urban canyon territory, too...but better than some older GPSes. Those situations are a real challenge for any GPS. It does not utilize GLONASS, though. From a pure accuracy standpoint, friends who have ridden under the same parking structure actually get fairly accurate tracks with the Garmin Edge 1000. The battery life on that one is just too terrible for me to want to spend my money on it, though.
    Regarding navigation....

    Who actually needs it? If you DO need it, and I mean really NEED it, is a Garmin 800-type GPS the right solution? I don't think it is, you'd want an Etrex with a longer battery life, easier recharging/battery replacement and more ease of use.

    If anyone wants to navigate their local, or really any established trail, just use MTB Project. If you want to navigate the backcountry, get an Etrex.

  13. #13
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    I dunno, man. I don't see any major problems there. It matched you to several segments in the area. There are really only two other people on the Strava Flyby. One guy has a known GPS - an Edge 510. Yeah, yours may be a touch less accurate than his, but it's not a deal breaker to me. The other one used a phone. Unfortunately, all we know is that it was an Android phone. And that one was LESS accurate than yours, it looks like.

    If you want more accurate GPS tracks than what you have now, you're going to have to spend quite a bit of money for that extra accuracy.

    Don't get too bent out of shape regarding the trails as they're shown on the basemap, either. While the accuracy generally is pretty good, they're never perfect.

    https://www.strava.com/activities/500742947

    Here's a local trail nearby that I rode recently with my Bryton Rider 310. I picked up every segment along the trail, and my track's far from perfect. One guy that shows up on the Flyby is a guy with an unknown iphone, but it's clear that his track is less accurate than mine. There's another guy with an Edge 520, and I think his is more accurate than mine by a touch. The southern portion of the trail is in a meadow with very easy GPS reception and his is right on the labeled trail (which is also probably more accurately marked on the map than the wooded northern portion). He only did one lap, though, so it's hard to see how repeatable the results are for his ride. But the major lesson is that we both got matched to the segments even though my GPS is a little less accurate. Strava can be fairly forgiving in that regard. It also means that the leaderboards are far from perfect. Your results can and will get fudged.

  14. #14
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    Quote Originally Posted by jmal View Post
    We met on the trail and then rode together for a little bit. The segment, The Juicy Deuce, is missing from mine but shows on the other rider's ride. About 4.3 miles in.
    The GPS error, which even exists in your buddy's ride, just missed the point were it triggers the beginning of the segment. You can see on the other ride that even though he obviously rode the same trail in opposite directions, the tracks are offset. All of that is pretty normal.

  15. #15
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    Quote Originally Posted by richde View Post
    Regarding navigation....

    Who actually needs it? If you DO need it, and I mean really NEED it, is a Garmin 800-type GPS the right solution? I don't think it is, you'd want an Etrex with a longer battery life, easier recharging/battery replacement and more ease of use.

    If anyone wants to navigate their local, or really any established trail, just use MTB Project. If you want to navigate the backcountry, get an Etrex.
    Define need. Nobody really needs it. Carry a paper map for navigation.

    A map on the GPS provides very nice quick reference navigation capability, even as compared to digging out the phone and booting up your favorite navigation app. The GPS can also do things with its navigation capability. That's especially the case for following a route that's been preloaded into the GPS. The phone can do that, too, but phones these days are too damn big to put on the handlebars. The GPS is made to go right there.

    Most trails I ride, I don't need navigation. I know my local trails very well. But quite regularly, I go places that I DON'T know like that. Some places that I only sorta know. And some places I've never visited at all. When I ride, I prefer to keep my phone off while it's in my pack. It's a tool for contact that I only turn on when I need to contact someone. I want maps to be more accessible than that. A mapping GPS becomes awful handy because the maps are a button press away. As to whether a mapping Edge or an etrex is the better choice, it's not a simple answer. It depends. People used etrexes on their bikes for years before the Edge came out. It will do great in that capacity, that's for sure. But there are some subtle software differences that make the Edge series the clear choice for certain types of riding. The etrex isn't going to be all that useful to you if you also ride a road bike and if you also spend time on the trainer. Or if you ride with a power meter in any of those situations.

  16. #16
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    I guess what got me thinking about all this is the ride I did last Sunday. There is a segment that is a climb that got dropped. It's not quite a mile and climbs about 1,000 feet. Everyone else recorded it just fine, but mine is missing. I don't mind small stuff, but when I climb for 30+ minutes, I'd like to have it in my data. My top speed was weird on that ride too, as well as elevation. I think my elevation was high, but knowing the area, I also think others' was low.

  17. #17
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    Quote Originally Posted by jmal View Post
    I guess what got me thinking about all this is the ride I did last Sunday. There is a segment that is a climb that got dropped. It's not quite a mile and climbs about 1,000 feet. Everyone else recorded it just fine, but mine is missing. I don't mind small stuff, but when I climb for 30+ minutes, I'd like to have it in my data. My top speed was weird on that ride too, as well as elevation. I think my elevation was high, but knowing the area, I also think others' was low.
    The Lezyne Power GPS doesn't have a barometric altimeter. It uses GPS altitude instead. The elevation is unlikely to match the elevation from a different Garmin GPS with a barometric altimeter, as they are recorded differently.

    Do the (Lezyne) GPS devices have a barometer?
    "Our GPS devices do not use a barometer. We have the latest GPS chip technology (Power and Super use both US and Russian satellites) and advanced GPS programming to consistently read within 5 – 10 meters of a fixed elevation point. While barometers can boost accuracy, they are weather sensitive and require regular calibration. With the reliability and simplicity of our optimized GPS system we concluded that a barometer wasn’t necessary at this time."

    Lezyne - Engineered Design - Support - FAQ

    Looking at the Strava ride you posted a lot of it is under tree cover. That can affect GPS accuracy for any model. You're also shown as travelling at low speeds (3mph) on the climbs. When moving slowly that can negatively affect GPS accuracy too. The worst sections of GPS track, where it is wandering off course, look to be at around the slowest points of the ride.

    The Garmin Edge 500 is notorious for having relatively poor GPS accuracy on anything but open terrain. If you're after GPS accuracy a Garmin Edge 500 wouldn't be an improvement!

    A Garmin Edge 520 might be better, as you can enable 1 second recording. It also has a barometric altimeter. If the tree cover where you ride is very thick you could still potentially run into reception issues though.

  18. #18
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    WR304, It's not the elevation discrepancies that I worry about. I understand that there are differences between platforms. It's really just missing segments that my iPhone and others' Garmins do not miss. I also understand how slow climbs can be a problem, though they don't seem to be for others that are riding even more slowly and using different platforms. However, the segment that dropped on the ride posted above was a steep drop that is fairly fast. Good to know that the Garmins are not any more or much more accurate. I think I'll just deal with the Lezyne for now. I need new bibs anyway, so I'll spend the cash there.

  19. #19
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    Quote Originally Posted by jmal View Post
    WR304, It's not the elevation discrepancies that I worry about. I understand that there are differences between platforms. It's really just missing segments that my iPhone and others' Garmins do not miss. I also understand how slow climbs can be a problem, though they don't seem to be for others that are riding even more slowly and using different platforms. However, the segment that dropped on the ride posted above was a steep drop that is fairly fast. Good to know that the Garmins are not any more or much more accurate. I think I'll just deal with the Lezyne for now. I need new bibs anyway, so I'll spend the cash there.
    You will always see fast downhills result in less accurate tracks. Any GPS will do that. A few factors will make it worse: Forest cover, the terrain itself (especially if you are in the bottom of a deep valley or canyon with steep sides, or on the northern slope of a hillside), tall buildings, that sort of thing. All GPS receivers get less accurate. When signals are bouncing off of stuff, it makes things more difficult. Newer, higher end models from companies that have been in the game a long time will tend to have algorithms that help process that multipath error into useful data, too. Less frequent recording intervals make it worse, too.

    SOME phone apps do this better than others, also. Phones have problems in these same circumstances. A low quality app that does very little data processing will be even worse. I have tried using people's geotagged photos from their phones in more remote places before. Holy cow. You wanna talk about garbage data? There's one area in particular I was working on. A guy with an iphone was sending me geotagged photos. His phone with the camera app running could barely receive a GPS lock in a lot of places as it was. When he had no GPS reception, the phone geotagged the picture with the location of the only cell tower in the area, which was over a mile away (probably because the phone remembered the last known location of that tower, not necessarily because he had a cell signal at the time - I'd suspect that he had no cell reception while he was out on the trails because if he had cell reception, he should have had GPS reception). He took some nice photos, but I couldn't use them for my project because the embedded coordinates were crap. This is a prime indication that GPS apps on phones are doing a LOT of processing to supply useful tracks.

  20. #20
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    There's a big difference in GPS accuracy between a Garmin Edge 500 (released in 2009) and a Garmin Edge 520 (released in 2015).

    The Garmin Edge 520 (with 1 second recording enabled) may well fare better than the Lezyne Power GPS (which appears to use some form of smart recording) for picking up Strava segments. It's still down to GPS reception though, with all the caveats that entails.

    With a Garmin Edge if you have a power meter connected that automatically sets it to 1 second recording mode (over riding any other recording settings). It's possible to connect a bluetooth enabled power meter to the Lezyne Power GPS (it doesn't support Ant+) which might do the same, automatically set the Lezyne Power GPS to 1 second recording mode. That is an expensive test though.

    Is your Lezyne Power GPS on the newest firmware version? If it's not on the latest firmware there might be some additional options added?

  21. #21
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    Yes, it's up to date on the firmware. I just got back from a road ride with it and it lost the entire ride. Frustrating to say the least. I bought it based on good reviews and the desire to have something more robust than my iPhone, as my iPhone was crashing in cold temperatures. Other than the cold weather issue, my iPhone was much more reliable. It never dropped a ride and didn't miss segments. Not sure if I'm going to go old school and ride without a computer, or buy something else. These are expensive mistakes if they don't work as intended or desired. I don't expect perfection, but I would like to be able to trust my GPS most of the time.

  22. #22
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    Did the Lezyne Power GPS save a .fit file on the device for your ride today? If you have a corrupt .fit file it may be possible to repair it and recover the information.

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    Nope. It did not save anything.

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    Lezyne Power GPS

    Try calling them. They are on the west coast but good support there when I called them which more than I can say for Garmin. Depending on how the segments were created in Strava the segment may not be very accurate when it was created and the GPS may not recognize the track as being on course.



    Quote Originally Posted by jmal View Post
    Nope. It did not save anything.

  25. #25
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    Looking at the recorded information for this ride I think it's fairly safe to say that your Lezyne Power GPS is using some sort of Smart Recording. Rather than recording every second it is frequently skipping between 1 and 4 seconds of recording. This is happening throughout the ride whilst you were riding and will impact on accuracy.



    The table above shows a section of ride, about 35 minutes in. The green arrows on the left show where the Lezyne hasn't recorded a point in that second. They are where there are momentary gaps in the recording.

    This is by design, not a faulty unit. If there isn't an option to change the recording interval in the device there isn't much that can be done. It's down to Lezyne to release a firmware update that would enable one second recording.

  26. #26
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    Try the "Don't see the segment you're looking for?" link at the bottom of your list of segments and see what it says for the Juicy Deuce segment and why it didn't match. Only you have that link available below your list of segments, so we are unable to do this on your Strava activity page.
    But based on other's comments on what appears to be Smart Recording by you Lezyne, I'm guessing that is the culprit. Try to find a setting on your GPS to change that to a fixed interval. Garmins offer 1 second intervals.

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    Quote Originally Posted by jmal View Post
    Yes, it's up to date on the firmware. I just got back from a road ride with it and it lost the entire ride. Frustrating to say the least. I bought it based on good reviews and the desire to have something more robust than my iPhone, as my iPhone was crashing in cold temperatures. Other than the cold weather issue, my iPhone was much more reliable. It never dropped a ride and didn't miss segments. Not sure if I'm going to go old school and ride without a computer, or buy something else. These are expensive mistakes if they don't work as intended or desired. I don't expect perfection, but I would like to be able to trust my GPS most of the time.
    Let me know what Lezyne's says. I am having the same issues. On the road and the mountain. I am so disappointed on the Unit and customer service. I talked to Adam in Lezyne's and he kept telling me bad data happens all the time. I sent data and info for a month of the issues, Lezyne couldn't care less.

    The smart GPS reading is not good for mountain biking unless is doing two or three second samplings. My lezyne does not pick a lot of the segments too.

    Inaccurate GPS locations from time to time.

    The android app is so primitive is a pain to share a ride.

    When racing with a big group the unit sometimes pick the HR sensor or Speed Cadence sensor from other racers messing my readings up.

    If I don't carry my speed cadence or HR sensor, it would connect to somebody's else in the middle of the race.

    I contacted Lezyne's numerous times to please fix the issues, Adam basically was saying it was my fault. I am personally going back to garmin sooner than later if an update does not come out soon. Please complaint to Lezyne to gain some pull to fix these issues.

    Thank you.

  28. #28
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    I have the new Lezyne Super GPS and it has been a fiasco. During my races and more worry is the unit is working correctly than enjoying the race.

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