# Garmin Edge 25 or Lezyne Power GPS?



## bosbik (Aug 29, 2011)

Hi,

I am looking into getting my first GPS computer and would like to have an HRM option. So I saw the garmin edge 25 and the lezyne power gps. they seem to have similar specs and I can get them almost at the same price.

so any opinions which is better?


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## Wish I Were Riding (Jan 30, 2004)

301 views and nobody has any advice. Bummer. I too am interested in the Power GPS. I still may go that way. Sorry I have nothing useful to add to your thread.


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## NordieBoy (Sep 26, 2004)

The Garmin 25 seems to be a bit crap.


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## rpearce1475 (Jan 24, 2015)

Steer clear of that Garmin. I had an Edge 20 (same GPS system, just no HRM capability) and it was very inaccurate. For instance, I would do what is known (via professional level geomapping for races) to be a 21.1 mile loop at my local trail, and the Garmin would say I had done 19.1ish. It was even worse if I did a ride with lots of fast downhills. The problem is that the sample rate simply isn't fast enough for twisty mountain bike trails, resulting in a lot of cut corners. I called Garmin about this, and they said it's fine because it's a product for "recreational riders", offered me no solution. I sold it to my roadie friend, it's worked fine for him so far. A Lezyne mini gps is next on the try list.


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## richde (Jun 8, 2004)

Your expectations are well beyond what pretty much any consumer GPS can deliver. Professional geomapping is way too labor intensive to replicate using a consumer GPS while riding, although if you walked slowly, you'd probably get closer to their results.


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## rpearce1475 (Jan 24, 2015)

richde said:


> Your expectations are well beyond what pretty much any consumer GPS can deliver. Professional geomapping is way too labor intensive to replicate using a consumer GPS while riding, although if you walked slowly, you'd probably get closer to their results.


I'm not expecting it to be 21 miles exactly (though my phone's GPS tends to be pretty close), but 10% off when my buddy's higher end Garmins are much closer to the mark is unacceptable


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## bosbik (Aug 29, 2011)

hey thanks guys..i expected as much and also from what I have read on the garmin edge 20/25 it wont be able to keep up on the trail...time to look at other brands.


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## jmal (Jul 16, 2009)

I have the Lezyne Power GPS and so far I like it quite a bit. I have not compared it to a wheel based computer to see how accurate the distance function is, but it is nearly identical to my iphone in both distance and elevation which is good enough for me. I basically wanted something that worked as well as the iphone running strava, but had a long battery life and the ability to sync to strava. I also decided I wanted a GPS based elevation measurement. I felt like barometric units were too susceptible to weather changes and sensor malfunction. Riding in the mountains where weather can and does change quickly seems to create problems. They also seem to overestimate climbing. I realize that most people feel like GPS based elevation is not that accurate, but at least it is consistent in my experience. I can accept a little inaccuracy, but I don't like to see huge inconsistencies in known routes.


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## Harold (Dec 23, 2003)

jmal said:


> I have the Lezyne Power GPS and so far I like it quite a bit. I have not compared it to a wheel based computer to see how accurate the distance function is, but it is nearly identical to my iphone in both distance and elevation which is good enough for me. I basically wanted something that worked as well as the iphone running strava, but had a long battery life and the ability to sync to strava. I also decided I wanted a GPS based elevation measurement. I felt like barometric units were too susceptible to weather changes and sensor malfunction. Riding in the mountains where weather can and does change quickly seems to create problems. They also seem to overestimate climbing. I realize that most people feel like GPS based elevation is not that accurate, but at least it is consistent in my experience. I can accept a little inaccuracy, but I don't like to see huge inconsistencies in known routes.


I suppose that depends on your environment. It may be sorta hidden or very small, but your GPS will tell you when it is able to obtain a 3D position fix, and when it only has a 2D position fix. Obtaining a 3D position from the GPS birds depends a lot on your surroundings, but also on satellite constellation geometry. A 3D fix can require as little as 1 additional satellite fix, but as many as several more, depending on the position of the satellites in the sky the GPS already has a fix on.

I have seen on hikes where the GPS bounces from 3D to 2D positional fixes. I've not paid much attention on a bike ride, but I suspect it does even more because of the faster movement.

That GPS-based elevation measurement, consequently, I find to be LESS consistent. The accuracy of the GPS-based elevation measurement varies rather randomly over time.

Barometric pressure-based readings are more consistent. The problem with them is that they consistently increase or decrease when the weather changes. Calibration is absolutely essential to reduce or eliminate this drift. The earliest Garmin Edges didn't have the capability to calibrate the barometric altimeter in any way. I had an Edge 705 BITD. Garmin now offers a couple calibration methods. Many Edges will calibrate elevation based off of waypoints. Many of their GPSes across their lineup will use their "auto calibration" where they periodically use GPS based elevation to minimize drift. But the best way is with frequent manual calibration from known elevation points (like USGS survey discs). Pretty much only handhelds offer this kind of calibration. My Oregon also has a "Elevation Type" setting, where I can change it from "variable elevation" (meaning, I'm moving and the elevation will change) to "fixed elevation" (meaning I've stopped), which tells the GPS that changes in barometric pressure indicate changing weather, not changing elevation.

If you find that your barometric pressure measured elevation plot is affected by rapidly changing weather, you can always obtain elevation from DEM data. Which is what I'm always using if I'm using a GPS that lacks a barometric altimeter. It won't give me elevation while out on a ride, but afterwards, it works fairly well, though its accuracy still depends on the positional accuracy of each recorded point.


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## jmal (Jul 16, 2009)

Harold, you are clearly more versed in this stuff than I. My experience is limited to using my own simple devices and comparing with those that my friends are using. Which is correct, I do not know, but I do know that mine gives me readings that are consistent ride to ride whereas my friends get varied readings ride to ride. Perhaps with more knowledge they could set up their units to get more accurate data. I do know that they calibrate to a know start elevation, but I don't know if they have multiple waypoints. Anyhow, the Lezyne basically works like a sophisticated smartphone running strava. It does have additional capacities for power and HR that I do not use at the moment. It seems to have an outstanding battery life which is the primary reason I needed something more than my phone.


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## Harold (Dec 23, 2003)

jmal said:


> Harold, you are clearly more versed in this stuff than I. My experience is limited to using my own simple devices and comparing with those that my friends are using. Which is correct, I do not know, but I do know that mine gives me readings that are consistent ride to ride whereas my friends get varied readings ride to ride. Perhaps with more knowledge they could set up their units to get more accurate data. I do know that they calibrate to a know start elevation, but I don't know if they have multiple waypoints. Anyhow, the Lezyne basically works like a sophisticated smartphone running strava. It does have additional capacities for power and HR that I do not use at the moment. It seems to have an outstanding battery life which is the primary reason I needed something more than my phone.


From ride to ride, true, your measurements will have a more consistent overall total climbing number. Over time, though, you will absolutely encounter outlier rides where all the GPS data is just fubar. I had a ride earlier this year, shortly after I started also using a wheel sensor with my Garmin, where the GPS data was complete garbage. I checked the satellite constellations and PDOP numbers, and they were horrendous for a period of a few hours while I was riding that day. After about half a lap, I lost a position fix entirely, and didn't get it back for more than half an hour. Only thing that kept the file remotely useful for anything was the fact that I was running an external sensor.

However, from one individual reading to the next, the errors will vary by quite a lot more than a barometric altimeter. Call it "noise" if you will. A barometric altimeter reading is going to have far less noise than a ground-based GPS elevation calculation.

Take my ride yesterday. Just over 17mi.

GPS-based elevation numbers are around 1900ft of climbing with a max of 901. GPS reception was good that day, partly because all the leaves are off the trees this time of year. Elevation calculated from DEM data was around 900ft less, so just over 1000ft with a max of 843.

My ride: https://www.strava.com/activities/460787559
Uncorrected elevation numbers for my ride obtained here: https://connect.garmin.com/modern/activity/999684559

A topo map bears this out. Looking at the high point along the trails in this area, it does not cross the 850ft contour line.

I just compared my ride to that of a friend riding the same place I did. He rode about 28mi that day, with several pavement miles, but his GPS file covered the same trails I rode. I checked the high points of the two, and his barometric altimeter is within 2ft of the DEM-based "corrected" max elevation of my own ride. My GPS-only elevation for that spot, at over 900ft, is almost 60ft off, and that for a single point. It's no wonder the GPS-elevation climbing total is over 900ft more on mine.

My buddy's ride: https://www.strava.com/activities/460788315


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## bbqmike (Jan 5, 2016)

How can I distinguish what sensor the garmin is reading from on the connect site? I have the edge 25 and have a speed sensor, but my first big ride with it was off by 10%, same as the phone setup I replaced. My friend has a 520 with a speed sensor as well and his is dead on, on the same trail. (I did have glonass enabled) I am wondering if the wheel sensor on the 25 is only used for trainer mode? but I would like to verify that. (it could also just not have calibrated correctly).


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## Harold (Dec 23, 2003)

bbqmike said:


> How can I distinguish what sensor the garmin is reading from on the connect site? I have the edge 25 and have a speed sensor, but my first big ride with it was off by 10%, same as the phone setup I replaced. My friend has a 520 with a speed sensor as well and his is dead on, on the same trail. (I did have glonass enabled) I am wondering if the wheel sensor on the 25 is only used for trainer mode? but I would like to verify that. (it could also just not have calibrated correctly).


The Edge 25 is crap. It will always be off, no matter what sensors you're using. The recording frequency is just too low. The Edge 520 permits data to be recorded once per second, while the Edge 25 uses "smart" recording which will never record as often. Garmin's excuse is that the 20 and 25 are "basic" GPSes. I call BS. Lezyne (and a couple other companies) understand that "basic" functionality doesn't have to mean crap data, which Garmin doesn't seem to understand.

I don't know specifically about the Edge 25, but this is how the sensor thing has worked for Garmin in the past. At first, when Garmin supplied wheel sensors, the sensor data was only used when there was no GPS signal. So, for trainer use, or that weird random occasion when you were riding through a long tunnel, or if you were in deep forest and signal dropped out. There were problems with that. People found the wheel sensor to provide better speed/distance data all the time, especially on the mtb. So after eventually, Garmin changed things to allow the sensor data to always take precedence over GPS speed/distance when a sensor was present.

So I would assume this to be the case. But Garmin Connect doesn't tell you if the wheel sensor data is present, or being used, or not. So you can't tell just by looking there. What you can do is download the file and look at it in a text program like notepad. Find the data field from the wheel sensor. See what it's saying and compare with Garmin Connect. Another alternative would be to remove the wheel sensor and ride a loop of your local trails. Stop and save your ride. Then do another lap WITH the sensor. Stop and save your ride. Then compare the two to each other. They should be different from each other.


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## bbqmike (Jan 5, 2016)

Harold said:


> The Edge 25 is crap. It will always be off, no matter what sensors you're using. The recording frequency is just too low. The Edge 520 permits data to be recorded once per second, while the Edge 25 uses "smart" recording which will never record as often. Garmin's excuse is that the 20 and 25 are "basic" GPSes. I call BS. Lezyne (and a couple other companies) understand that "basic" functionality doesn't have to mean crap data, which Garmin doesn't seem to understand.
> 
> I don't know specifically about the Edge 25, but this is how the sensor thing has worked for Garmin in the past. At first, when Garmin supplied wheel sensors, the sensor data was only used when there was no GPS signal. So, for trainer use, or that weird random occasion when you were riding through a long tunnel, or if you were in deep forest and signal dropped out. There were problems with that. People found the wheel sensor to provide better speed/distance data all the time, especially on the mtb. So after eventually, Garmin changed things to allow the sensor data to always take precedence over GPS speed/distance when a sensor was present.
> 
> So I would assume this to be the case. But Garmin Connect doesn't tell you if the wheel sensor data is present, or being used, or not. So you can't tell just by looking there. What you can do is download the file and look at it in a text program like notepad. Find the data field from the wheel sensor. See what it's saying and compare with Garmin Connect. Another alternative would be to remove the wheel sensor and ride a loop of your local trails. Stop and save your ride. Then do another lap WITH the sensor. Stop and save your ride. Then compare the two to each other. They should be different from each other.


Here is an excerpt, I'll grab a log in training mode, but I have a feeling it is indeed not using the speed sensor under normal conditions:

<Trackpoint>
2015-12-31T17:41:01.000Z
<Position>
<LatitudeDegrees>40.84666161797941</LatitudeDegrees>
<LongitudeDegrees>-73.0155791155994</LongitudeDegrees>
</Position>
<AltitudeMeters>85.4000015258789</AltitudeMeters>
<DistanceMeters>222.11000061035156</DistanceMeters>
<HeartRateBpm>
<Value>155</Value>
</HeartRateBpm>
</Trackpoint>
<Trackpoint>
2015-12-31T17:41:06.000Z
<Position>
<LatitudeDegrees>40.84677670150995</LatitudeDegrees>
<LongitudeDegrees>-73.01577223464847</LongitudeDegrees>
</Position>
<AltitudeMeters>85.0</AltitudeMeters>
<DistanceMeters>243.13999938964844</DistanceMeters>
<HeartRateBpm>
<Value>157</Value>
</HeartRateBpm>
</Trackpoint>

the sample rate is all over place, sometimes it a 1 sec update, sometimes 5.


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## Harold (Dec 23, 2003)

bbqmike said:


> Here is an excerpt, I'll grab a log in training mode, but I have a feeling it is indeed not using the speed sensor under normal conditions:
> 
> ...
> 
> the sample rate is all over place, sometimes it a 1 sec update, sometimes 5.


Yep, that's "smart" recording for you. On top of just inherently missing some data, it's somehow actually LESS accurate. I don't know how Garmin managed that, but I can tell pretty easily when I run a track on a trail and forgot that the GPS was on "smart" recording. A map of the recorded file barely resembles what I actually rode. Something about the speed, I think, is what causes those problems because I don't see that if I use smart recording for slower paced activities.


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## bbqmike (Jan 5, 2016)

Thanks, wish I had found this forum before ordering the unit, but isn't that how it usually goes?


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## Harold (Dec 23, 2003)

bbqmike said:


> Thanks, wish I had found this forum before ordering the unit, but isn't that how it usually goes?


Such is life sometimes.

I'm just glad that other companies are actually listening to people and offering budget-friendly bike GPSes that use 1sec recording. Just because someone doesn't want an $800 bike computer doesn't mean they don't care about keeping accurate records of their riding.


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## bbqmike (Jan 5, 2016)

I grabbed a log in trainer mode and sadly it doesn't specify that the speed sensor is being used, the distance variable is the same, so time for something better, with 1s sample rate, I already have all the garmin sensors, so I'm going to stick with them.


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## Harold (Dec 23, 2003)

bbqmike said:


> I grabbed a log in trainer mode and sadly it doesn't specify that the speed sensor is being used, the distance variable is the same, so time for something better, with 1s sample rate, I already have all the garmin sensors, so I'm going to stick with them.


The nice thing about ANT+ devices is that they don't care what brand of device you use. You can mix and match them to your heart's content. If you have the magnetless Garmin sensors, you have to be a little careful, because those are a more recent addition. Basically, it's that the speed and cadence sensors are separated, and the heat unit needs to be compatible with separate speed and cadence. You can use them on an older head unit, but you'll be limited to using one or the other.


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## bbqmike (Jan 5, 2016)

In general, is there anyway to edit a garmin outside it's own menu system? all the configs are hex based when connected to USB, is there a program to read them? Not having an autopause adjustment is nagging issue #3 on this 25, and so far, I haven't scored a good deal on a 510/520 yet.


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## Harold (Dec 23, 2003)

bbqmike said:


> In general, is there anyway to edit a garmin outside it's own menu system? all the configs are hex based when connected to USB, is there a program to read them? Not having an autopause adjustment is nagging issue #3 on this 25, and so far, I haven't scored a good deal on a 510/520 yet.


I've never seen anything like that. If you want 1sec recording, you'll have to get something else.


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## bbqmike (Jan 5, 2016)

I wanted to set autopause to wait longer before pausing, sometimes it pauses while I'm still moving.


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## Harold (Dec 23, 2003)

bbqmike said:


> I wanted to set autopause to wait longer before pausing, sometimes it pauses while I'm still moving.


Yeah, that's Garmin's autopause for you. Turn that setting off, and let your software decide when you're stopped later.

That's another thing you just need to buy a different GPS if you want to change. But frankly, I don't even use it. If I'm pushing my bike up a steep azz 30%+ grade, I'll be moving slower than any autopause setting will be able to detect. I'm gonna stop for short periods on my way up for a quick breather and it's easier to just keep the GPS recording going. Any good software will be able to do its own calculations for that in post-analysis, and be able to be more consistent about it than your GPS head unit.


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## XJaredX (Apr 17, 2006)

Harold said:


> Yeah, that's Garmin's autopause for you. Turn that setting off, and let your software decide when you're stopped later.
> 
> That's another thing you just need to buy a different GPS if you want to change. But frankly, I don't even use it. If I'm pushing my bike up a steep azz 30%+ grade, I'll be moving slower than any autopause setting will be able to detect. I'm gonna stop for short periods on my way up for a quick breather and it's easier to just keep the GPS recording going. Any good software will be able to do its own calculations for that in post-analysis, and be able to be more consistent about it than your GPS head unit.


I'm about to get a 520, and it comes with a wheel speed sensor, isn't that what it is for? The speed sensor I mean. For slow speed maneuvers under the trees, etc


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## Harold (Dec 23, 2003)

XJaredX said:


> I'm about to get a 520, and it comes with a wheel speed sensor, isn't that what it is for? The speed sensor I mean. For slow speed maneuvers under the trees, etc


No. It is more complicated than that. It improves distance measurements at any time but especially the faster you go and the twistier the trail. Fast curves lose more than slow ones.


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