# Garmin Edge 500 accuracy, need help



## drbob20 (Apr 21, 2008)

I picked up an Edge 500 a few weeks ago, it's pretty cool but I'm not sure how accurate the mileage is. I did our usual thursday ride, the trail is somewhere around 6.5 miles. I used the lap feature and came up with 5.11, 5.54 & 5.29 miles on the three laps. in the parking lot I had a total of 17.17 miles while my riding partner using his wheel magnet computer showed 21 total miles. The other day I ended up with 26.72 while actual mileage was 29.42. I'm much more certain of the accuracy of my buddies wheel magnet computer because I've ridden the trails previous to owing the Garmin and have shown similar results. Anyone have experience or suggestions with this? Any help is appreciated.


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## ataylor (Dec 28, 2009)

make sure you have updated the firmware to the latest release.


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## drbob20 (Apr 21, 2008)

I have version 2.30 installed, I think it's the latest.


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## rjgarcia (Mar 24, 2010)

Are you using a speed/cadence sensor?

If not, you are using the satellites for position and speed and it doesn't take into account elevation changes as part of your distance. From the satellites perspective you are always traveling on flat ground for the distance calculations.


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## drbob20 (Apr 21, 2008)

Ok, i put the speed/cadence sensor and mileage is now accurate, thank you for the suggestion. Question though, will the unit automatically recognize that the spd/cadence sensor is there or do I need to go through the menu every time?


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## rjgarcia (Mar 24, 2010)

I believe it looks for it when it turns on, just like it does with the heart rate monitor, but I cannot confirm. On my Oregon, it finds it all by itself without me having to tell if after the first time.


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## D-Town (Oct 20, 2005)

drbob20 said:


> Question though, will the unit automatically recognize that the spd/cadence sensor...?


Yup. It will recognize the sensor with a "beep" sound when the unit starts up. It's the same for a power meter or hear rate monitor as well.


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## trailhunter (Oct 11, 2004)

My friend has the same issue, we did a similar ride and came up with a different reading, someone else advised that he should change his sampling rate which apparently effects memory space but is more accurate. Not sure if this is correct or not but may be someone else could add to this.


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## 1SPD (Apr 25, 2010)

Dang it! I am running into the same problem with mine. I thought it was cool that the thing woudl track it all but did not even think about the satellites looking at it all as flat ground even though it tracks elvation differences.

The good news is that I am actually riding farther than what it is telling me. But the down side is that I have to put a stupid sensor on my bike now. Wish I would have known this from the beginning as I would have purchased the bundle instead of individual pieces.


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## tshulthise (Apr 23, 2010)

I'm pretty sure you have to turn the GPS off to use the cadence sensor for mileage calculations. I haven't tried it yet because I'm pretty sure that will drop the GPS route information. Is that true? The manual is not clear how that works.

BTW, the accuracy is TERRIBLE with these things. If you want better than 20% accuracy then the GPS mileage is junk. Its not just hills that cause the problem. As indicated by the different distances logged for the same laps mentioned earlier. The GPS goes in and out a LOT when in the woods. I suspect the accuracy is much better on flat ground on a sunny day with no obstructions but how often does that happen. Never.


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## fishbum (Aug 8, 2007)

Accuracy of any GPS is great on a flat road in a straight line... add lots of small turns and the accuracy decreases because of the sampling rate. If your turn radius is 10' and that's your track interval then you miss a lot of the distance... Add to that all the short ups and downs that don't even register as a change in the track elevation and yes, the accuracy would be questionable. Then figure in the +/-30' horizontal GPS accuracy at any given moment, add tree canopy and other variables and you get what you get...
One thing is certain - it's better than it used to be and will keep getting better.


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## slocaus (Jul 21, 2005)

tshulthise said:


> I'm pretty sure you have to turn the GPS off to use the cadence sensor for mileage calculations. I haven't tried it yet because I'm pretty sure that will drop the GPS route information. Is that true? The manual is not clear how that works.
> 
> BTW, the accuracy is TERRIBLE with these things. If you want better than 20% accuracy then the GPS mileage is junk. Its not just hills that cause the problem. As indicated by the different distances logged for the same laps mentioned earlier. The GPS goes in and out a LOT when in the woods. I suspect the accuracy is much better on flat ground on a sunny day with no obstructions but how often does that happen. Never.


The 305 and 705 only use the GSC10 if the unit looses GPS signal for a significant time, or if you turn the GPS off. The 500 changed that and will use the GSC10 to augment the GPS signal; it will be most accurate if you calibrate the GPS by doing a wheel roll out.

Turn on one second recording to get the most accurate tracking. GPS elevation is a tough one, since you are moving closer and away from the 22000 mile geosynchronous satellites, and not perpendicular, so the barometric altimeter helps, but then barometric pressure changes during the day. Gah!  

The final solution is that the software you load the track into on your computer can do corrections to track and elevation based on known points in the maps and give you very close to real accuracy. TopoFusion is the most accurate, and allows you to control how the corrections are done. Using DEM data works best for me in central coastal California. YMMV. :thumbsup:


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## EBrider (Aug 3, 2004)

I noticed on a 5.75 mile stretch of trail with about 2k in elevation change, it short changed me about half a mile. I may get an extra cadence sensor and put it on my mountain bike. It appears that it uses my cadence/wheel sensor on the road bike to calculate distance and speed. It calibrated the wheel diameter with GPS.


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## chiplikestoridehisbike (Aug 8, 2007)

Slocaus:

"Turn on one second recording to get the most accurate tracking" how do you do this on a 500? I have read something about the power meter but am unsure. Do you just enable the power meter weather or not you actually have one?


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## slocaus (Jul 21, 2005)

chiplikestoridehisbike said:


> Slocaus:
> 
> "Turn on one second recording to get the most accurate tracking" how do you do this on a 500? I have read something about the power meter but am unsure. Do you just enable the power meter weather or not you actually have one?


I guess you cannot, sorry. I had a 305 for years and now the 705. They had basically the same settings, and I assumed the 500 did as well, with some additional features. I just looked at the 500 manual. It sound like you have to have a power meter to get one second recording, but try turning the ANT+ feature on and see?

To me this is more proof that the 500 is a great road computer, but not for off road. This is one example, but you do not have multiple tight turns / switchbacks with rolling ups and downs in road biking. That is where one second recording really makes a big difference.


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## Harold (Dec 23, 2003)

slocaus said:


> I guess you cannot, sorry. I had a 305 for years and now the 705. They had basically the same settings, and I assumed the 500 did as well, with some additional features. I just looked at the 500 manual. It sound like you have to have a power meter to get one second recording, but try turning the ANT+ feature on and see?
> 
> To me this is more proof that the 500 is a great road computer, but not for off road. This is one example, but you do not have multiple tight turns / switchbacks with rolling ups and downs in road biking. That is where one second recording really makes a big difference.


agreed...I live by 1sec recording. Maybe you get it on the 500 if you use the HRM, too? seems to me you'd want 1sec recording when you're using the HRM.


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## chiplikestoridehisbike (Aug 8, 2007)

Thanks Slocaus. I'll post the outcome.


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## tshulthise (Apr 23, 2010)

I went through every screen and put them in Excel just to make sure I didn't miss anything and to have a reference for the future. There isn't a "1 second tracking" feature on the 500. The 350 had it but the 500 doesn't show one anywhere that I could find. I'm pretty sure I went through every screen.


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## tshulthise (Apr 23, 2010)

Also, I turned on the cadence sensor and entered a wheel size and it still doesn't read accurate MPH under trees and the mileage is usually low by about 10-20%.


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## chiplikestoridehisbike (Aug 8, 2007)

I added a speed sensor and have been using a heart rate sensor. Wheel sensor seemed to make speed and distance more accurate. (see other post) 500 seems to record data well. I will see if I can disect one of the graphs. One thing I noticed was a post ride track exported to Google Earth was much smoother than Garmin's online software. There has been discussion of this over on the garmin about the display of their software. Topofusion is mentioned as giving very accurate displays. So far very happy with the 500. 705 is probably a better unit, but 500 does what I want.


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## russ3706 (Feb 15, 2007)

Hopefully the next Garmin cycling unit will be WAAS enabled like many of their other units, then we can forget the current inaccuracies to a large extent. WAAS is typically accurate to about 3 feet horizontal and 4' vertical all but a fraction of a percentage of the time, at least thats what development engineers I fly around doing GPS testing tell me. Of course tree coverage will affect it some, but it would be a move in the right direction. I'm quite surprised the 705 does not have it, especially at its pricepoint, seeing as how an automotive unit I purchased last year for $125 was WAAS enabled...


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## Harold (Dec 23, 2003)

russ3706 said:


> Hopefully the next Garmin cycling unit will be WAAS enabled like many of their other units, then we can forget the current inaccuracies to a large extent. WAAS is typically accurate to about 3 feet horizontal and 4' vertical all but a fraction of a percentage of the time, at least thats what development engineers I fly around doing GPS testing tell me. Of course tree coverage will affect it some, but it would be a move in the right direction. I'm quite surprised the 705 does not have it, especially at its pricepoint, seeing as how an automotive unit I purchased last year for $125 was WAAS enabled...


to be honest, WAAS is not all it's cracked up to be. it's a drain on battery life and with modern receiver chipsets that are able to process multipath and all that, WAAS is largely unnecessary.

GPS applications in an aviation environment are different than in a forested one. might well be worth it to pilots, but I'm not missing it on my E705, which is just as accurate as my 76CSx that does have it.


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## slocaus (Jul 21, 2005)

Failure Imminent for WAAS GEO Satellite
April 15, 2010 link

One Of Two WAAS Satellites Failed

The Wide Area Augmentation System, which broadcasts GPS corrections used by aviators across North America, is powered by just two satellites, and one of them has failed. Intelsat, the company that provides the satellite service to the FAA, lost control of the satellite on April 3. The satellite will "drift out of orbit over the next two to four weeks," the FAA said on April 12. The most immediate impact will be felt in northwestern Alaska, where service will be unavailable at 16 airports. However, the FAA said that due to the lack of redundant coverage, WAAS users across North America may experience temporary service interruptions. Also, a "single-point failure situation exists until redundancy [is] restored," the FAA said. A replacement satellite should launch by the end of this year; meanwhile, the FAA is looking at other options to mitigate the impact.

The Government Accountability Office raised questions last year about the lack of redundancy in the GPS system. "It is uncertain whether the Air Force will be able to acquire new satellites in time to maintain current GPS service without interruption," the GAO report warned. "If not, some military operations and some civilian users could be adversely affected." Click here for more details about the outage, in an FAA PowerPoint presentation. link

FAA Predicts Erosion of GPS WAAS Service Due to Intelsat GEO Failure

still more


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## Harold (Dec 23, 2003)

slocaus said:


> Failure Imminent for WAAS GEO Satellite
> April 15, 2010 link
> 
> One Of Two WAAS Satellites Failed
> ...


Here in Texas, I'm still getting WAAS on my 76CSx, so I'm not sure if there's an erosion of service at the moment for my area.


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## bosp7 (Nov 21, 2008)

russ3706 said:


> Hopefully the next Garmin cycling unit will be WAAS enabled like many of their other units, then we can forget the current inaccuracies to a large extent. WAAS is typically accurate to about 3 feet horizontal and 4' vertical all but a fraction of a percentage of the time, at least thats what development engineers I fly around doing GPS testing tell me. Of course tree coverage will affect it some, but it would be a move in the right direction. I'm quite surprised the 705 does not have it, especially at its pricepoint, seeing as how an automotive unit I purchased last year for $125 was WAAS enabled...


WAAS doesn't help. I ride with a Garmin Etrex Vista Hcx and on a trail that I know is 13 miles long, it consistently indicates 11.5 miles. That's with the track point rate at 1 second and WAAS enabled.


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## JHANguyen (Jun 9, 2009)

Would you guys recommend getting the 305 over the 500?

I'm in the market to get a GPS and am deciding between the two. Not looking for any mapping futures, just regular cycling computer + the ability to share/compare online.


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## tshulthise (Apr 23, 2010)

JHANguyen said:


> Would you guys recommend getting the 305 over the 500?
> 
> I'm in the market to get a GPS and am deciding between the two. Not looking for any mapping futures, just regular cycling computer + the ability to share/compare online.


I've had both. I tried two refurbished 305's from Amazon and neither would work with the cadence sensor so I sent them back. Other than that I liked the 305.

The 305 is larger but has the capability to use a "virtual trainer" so you can race against yourself if you ride the same course over.

The 500 is smaller and has three screens that you can customize whereas I think the 305 may only have one or two. I like the mount better for the 500. I've read complaints that the 305 mount breaks easy and that the battery terminals fail after a year or so. The 500 has a barometer so you can track elevation changes. I like that added feature. I've read but am not sure that the 500 uses a combo of the wheel magnet and GPS to determine speed and distance. I.E. it uses the magnet when the GPS signal is low. I'm pretty sure the 305 only lets you use one or the other and you have to turn the GPS off if you use the wheel magnet.

Hope that helps. Short version is I like the 500 better but I would like to have the virtual partner (but who knows if I'd really use it).


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## JHANguyen (Jun 9, 2009)

tshulthise said:


> Hope that helps. Short version is I like the 500 better but I would like to have the virtual partner (but who knows if I'd really use it).


I thought the Edge 500 has virtual partner?

On the Garmin website it says, "Virtual Partner® (train against a digital person): yes (within a course) "


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## tshulthise (Apr 23, 2010)

JHANguyen said:


> I thought the Edge 500 has virtual partner?
> 
> On the Garmin website it says, "Virtual Partner® (train against a digital person): yes (within a course) "


My Garmin 500 does NOT have Virtual Partner. I looked on the Garmin website at the Edge 500 and its not mentioned there either. The Edge 305 has it.


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## slocaus (Jul 21, 2005)

tshulthise said:


> My Garmin 500 does NOT have Virtual Partner. I looked on the Garmin website at the Edge 500 and its not mentioned there either. The Edge 305 has it.


Um......

http://www8.garmin.com/manuals/Edge500_OwnersManual.pdf

page 2
page 17
page 19
page 20
page 62

This comparison shows both have virtual partner.



tshulthise said:


> The 500 has a barometer so you can track elevation changes.


Barometric altimeter: yes 
https://buy.garmin.com/shop/shop.do?cID=160&pID=331#specsTab

Fourth item up from the bottom on the specs tab.


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## snellvilleGAbiker (Apr 30, 2009)

*same problem*

I just purchased edge 500 and having the same accuracy problem but only on the trail. On the road, it's pretty good but when i hit the trail, the accuracy is terrible. My trail loop is about 8 mi long, but it's been recorded at 5.9-6.4 mi. As the result, the mph is not accurated either. 
Is Garmin gonna put out a "recall"?

I have a forerunner 305 and it's only off by .5-.6 mi. But i lost it. I should just purchase another one instead of this POS


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## slocaus (Jul 21, 2005)

snellvilleGAbiker said:


> I just purchased edge 500 and having the same accuracy problem but only on the trail. On the road, it's pretty good but when i hit the trail, the accuracy is terrible. My trail loop is about 8 mi long, but it's been recorded at 5.9-6.4 mi. As the result, the mph is not accurated either.
> Is Garmin gonna put out a "recall"?
> 
> I have a forerunner 305 and it's only off by .5-.6 mi. But i lost it. I should just purchase another one instead of this POS


The Edge 500 was designed as a road bike computer. It has a different algorithm for "smart recording" than the Edge 2/3.6/705 series, from the research I have found in the various GPS and bike forums.

What that means is that in the 500, the track is only marked on changes in direction or speed, but essentially at a slower rate than in the other series. Roads do not change direction or elevation as much as trails, obvious, I know, but think about it. If you design a road computer, design it to lay down a bread crumb track point less often, since roads are designed to go as straight and level as possible. You can build a smaller GPS with longer battery life.

If you want more frequent track points with "smart recording" or 1 second recording, then build that into the 2/3/6/705 series that is designed for off road or on road. It will be slightly larger, but much more practical for off road and on road use combined.

You can turn on 1 second recording in the 2/3/6/705, but you can only turn on 1 second recording in the 500 if you have a power meter installed and enabled (enabling power and 1 second recording does not make any difference if the 500 is not paired with a power hub according to reports I have read). You can add a GSC10 (or other ANT+ aftermarket sensors) and the 500 will share it for better accuracy, unlike the 2/3/6/705 that only uses it if the signal is lost or the GPS turned off, as stated above. There is a thread about this here and many of them in the Garmin Forums.

The other essential is to update to the newer firmware, have you done that?


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## tshulthise (Apr 23, 2010)

slocaus said:


> Um......
> 
> http://www8.garmin.com/manuals/Edge500_OwnersManual.pdf
> 
> ...


Interesting. I haven't set up any courses so the Virtual Partner might be buried in that menu somewhere and my not show on the menu unless you have courses programmed. Its not as easy to get to as it is on the 305. I remember it being on the menu on the 305 without any courses input and its not on the 500. Its also possible that a newer firmware version has it also. I don't have the latest firmware uploaded yet but I just bought mine about two months ago.

That list also says the 305 has a barometric altimeter. I think I got that confused with the temperature. The 500 has a temperature sensor and the 305 does not. Both have a barometric altimeter.


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## adamant76 (Jan 9, 2009)

I just got a 500 as a gift from my lovely wife...so far I really like it. I was not aware of the accuracy problems as I went from nothing to Garmin500. I will have to monitor that now. My question is if anyone has had luck on Geoladders with the Garmin 500 yet? I can't seem to upload. The Garmin COnnect works great, but I want to get on Geoladders.

thanks,
Adam


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## slocaus (Jul 21, 2005)

adamant76 said:


> I just got a 500 as a gift from my lovely wife...so far I really like it. I was not aware of the accuracy problems as I went from nothing to Garmin500. I will have to monitor that now. My question is if anyone has had luck on Geoladders with the Garmin 500 yet? I can't seem to upload. The Garmin COnnect works great, but I want to get on Geoladders.
> 
> thanks,
> Adam


The Edge 500 has its own proprietary format for uploading data (.FIT), and it seems that Garmin has not shared that with other developers yet. From what I can see, you will have to upload to GC, export as tcx or gpx and import to Geoladders, maybe.......

When the 705 came out it was like that in using TCX (a Garmin invention) and not GPX, so many third party software like SportTracks and TopoFusion had issues. It does not seem like most of the other ones have been able to solve the Edge 500 FIT format yet. You might want to pursue it with Google, I did a bit, but since I do not have that issue, I leave it up to you. Have fun.


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## btx (Jun 2, 2006)

So, what's the verdict on this thing? I was about to buy one for road and off road use without power meter or HRM. I use my old Etrex on my roadie and nothing on my MTB at the moment.


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## slocaus (Jul 21, 2005)

btx said:


> So, what's the verdict on this thing? I was about to buy one for road and off road use without power meter or HRM. I use my old Etrex on my roadie and nothing on my MTB at the moment.


Road bike GPS get the 500.
Mountain bike GPS get the 705.
If you ride both bikes, get the 705 to get the best for both.


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## tshulthise (Apr 23, 2010)

btx said:


> So, what's the verdict on this thing? I was about to buy one for road and off road use without power meter or HRM. I use my old Etrex on my roadie and nothing on my MTB at the moment.


If you use the wheel magnet and turn it on then it will give you accurate mileage readings even under tree cover. The elevation feature seems to be decent if you turn on "elevation corrections" in Garmin connect. If you don't need the maps and it you don't want to have the function where it shows you how far ahead or behind you are from a previous ride then I think its the one to get. After learning how everything works I really like the 500.


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## slocaus (Jul 21, 2005)

tshulthise said:


> If you use the wheel magnet and turn it on then it will give you accurate mileage readings


You still only get "smart" recording at the longer track point intervals that the 500 uses for "straight line road biking", and not the one second recording, or the quicker tracking algorithm that the 705 uses to track frequent directional changes, like swoopy, flowy trail, and especially switchbacks. That messes with elevation too, which is why you have to futz with GC when you use the 500 for mountain biking.

If you want Virtual Partner, remember that the 705 has that too, as well as power. The only thing I can find that the 705 does NOT have that the 500 does is temperature.

Also,if you want to use the numerous third party track sites, like GeoLadders,and some of the third party software, like TopoFusion, then the proprietary FIT files from the 500 cannot be directly uploaded to those sites / programs.

This take me back to the 500 as a road bike computer only, where you will use limited analysis programs, Garmin Training Center, Garmin Connect, WKO+ or maybe Cheetah. If you road and mountain bike, and want to use _every other site / analysis program available_, get the 705.


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## btx (Jun 2, 2006)

Or the 305, correct? Those things are going for under 200 as refurbs....


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## tshulthise (Apr 23, 2010)

slocaus posted some good information for folks who don't mind spending the extra $$ and who want more detailed analysis than Garmin Connect provides.

U can set the 305 to one second recording. I tried two refurbished 305's from Amazon and neither worked with the cadence sensor so I sent them back. Also, I don't think the 305 will use BOTH the GPS and the wheel sensor simultaniously. It uses one or the other. I think you have to turn the GPS off to use the wheel sensor but I'm not 100% sure about that.

My Edge 500 was within a couple tenths of a mile accuracy with the wheel sensor connected on a winding 12 mile mtb trail under the trees. That's close enough for me to save the extra $$. Here's an example http://connect.garmin.com/activity/41993392

I just use Garmin Connect for basic analysis so the 500 is ideal for me.


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## drbob20 (Apr 21, 2008)

After 44 rides & 1000 miles using my wheel/cadence sensor on my mtn bike all seems to be well & accurate. I don't ride my rd bike as much so I don't use the wheel/cadence sensor on it. I think using on both would be ideal but having to switch from mtn to rd bike on the unit will be a hassle and I"m sure I'd forget to do it. If that happened I'd be riding my rd bike and it would use the mtn wheel size and I'd be all messed up. So for now I'll keep the cadence/wheel sensor on the mtn bike and not worry about the accuracy issue on the rd bike.


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## EBrider (Aug 3, 2004)

If you get cadence sensors for both bikes, the unit will differentiate between bikes. You set up bike 1 and bike 2.

For me, the 500 is perfect. Has all the info I need, compact and reasonably accurate. If I'm training for something, its more based on time than miles. And if I'm not training, I don't care how far I rode. So if its off a mile or two after a long ride, it really doesn't matter.


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## slocaus (Jul 21, 2005)

btx said:


> Or the 305, correct? Those things are going for under 200 as refurbs....


Yes, most settings and firmware are the same. No mapping of course, and some other slight differences. The 305 does not have the menu lock that I like and use every ride on my 705.



tshulthise said:


> slocaus posted some good information for folks who don't mind spending the extra $$ and who want more detailed analysis than Garmin Connect provides.
> 
> U can set the 305 to one second recording. I tried two refurbished 305's from Amazon and neither worked with the cadence sensor so I sent them back. Also, I don't think the 305 will use BOTH the GPS and the wheel sensor simultaniously. It uses one or the other. I think you have to turn the GPS off to use the wheel sensor but I'm not 100% sure about that.
> 
> ...


Of course you can get cadence / speed and HRM at the same time on 305 and 705 as well as the 500! Why would you not be able, they are training / fitness GPSs?

If I am going to set on a trainer in the middle of winter, I expect to get both speed / distance / cadence and heart rate data, and Garmin delivers. (I do not ride trainers indoor anymore, I live in California with 300+ days of sun, no snow, and minimal rain, and exorbitantly high COL for a reason - so I can ride year 'round.) rft:


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## Toff (Sep 11, 2004)

The more I use the 500 the more I dislike it.

I find it to be very unreliable. Under light tree coverage I can watch my speed go anywhere from 13 to 20 mph on a straight line. While everyones 305 broke eventually at least it recorded speed/mileage decently.

The recent update finally got it to start more quickly tho.

I wouldn't buy it again.


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## phatfreeheeler (Mar 3, 2005)

Just downloaded 2.40 (Lots of updates), we'll see how that runs. I actually have not had a problem with the 500 since I did the first firmware update after buying it. I like it, but I do wish I could make it record at 1 sec intervals. I will never use a power meter, but just want clearer tracks on trail. I want to see every switchback. Supposedly the smart recording function has been updated so we'll see. I'm gonna talk to a rep at the OR show about it.


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## Frodo1095 (Jul 19, 2010)

I am interested with regards to all these posts quoting the inaccuracy of the edge 500 for measuring distance (in mtb's) due to elevation and sharp turns vs sampling rate.

But what are you using for comparison ?
Old bike computers with a wheel magnet that relies on an inputted wheel diameter that takes no account of tread depth, tyre pressure which would vastly alter the rolling daimeter of any given tyre and would not neccessarily conform to the one figure you can pick in your computer.

I am not trying to say anyone is a liar or misleading.

I am looking at buying an edge 500 for my mtb rides to aid with training as well as mapping, plus I like the idea of using gps instead of a wheel magnet.
I didnt want to have to put on a speed / cadence sensor in order to get accurate info

But if it is so far off why would anyone buy one and is it that far off beacause off all the tree cover and signal drop out ?
How would a 705 be better ?

The more I read the more confused I seem to get


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## 3034 (Apr 12, 2006)

I had the edge 305 for 3 years (broke)
I currently have the edge 500
all for mtn biking

DO NOT GET THE edge 500 for mtn biking
poor accuracy


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## tshulthise (Apr 23, 2010)

Go here http://connect.garmin.com/activity/46556417 and play with all the functions on the page. That is why we buy a GPS bike computer. You can also look at all your training events over a period of time. I use it as a motivational device to try to keep my mileage and calorie count up from month to month.

You can NOT consistently get very accurate distance from an Edge GPS under heavy tree cover. Its just not sensitive enough. The wheel sensor takes care of that problem on the 500. I don't think the 305 uses both GPS and the wheel sensor at the same time but you choose either/or but if you choose to use the wheel sensor you loose the GPS tracking. Someone correct me if I'm wrong there. I'm not sure about the other models.

Wheel sensors are the most accurate measure.

I didn't get the 705 because its more expensive the mapping function wouldn't be helpful for where I ride and the screen is so small it would be of limited utility to me.

If you just want accurate distance then go with a Cateye bike computer. Very inexpensive and relatively accurate if you set it up correctly. If you want the GPS tracking and review of all your stats then the Edge series is great. Whatever motivates you to ride more is the right choice.


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## slocaus (Jul 21, 2005)

Frodo1095 said:


> I am interested with regards to all these posts quoting the inaccuracy of the edge 500 for measuring distance (in mtb's) due to elevation and sharp turns vs sampling rate.
> 
> But what are you using for comparison ?
> Old bike computers with a wheel magnet that relies on an inputted wheel diameter that takes no account of tread depth, tyre pressure which would vastly alter the rolling daimeter of any given tyre and would not neccessarily conform to the one figure you can pick in your computer.
> ...


You got it with the "sampling rate". The 500 has a slower sampling rate to allow smaller size, lighter weight and still keep long battery life. That sampling rate assumes you are doing mostly straight line riding with few abrupt, short radius turns at slow speed, i.e., it is designed for road biking.

When used for mtn biking, that slow sampling rate means that distance and speed are skipped between samples, resulting in errors. Add the wheel sensor, and that will correct it since the magnet is read every wheel revolution. The 500 does integrate the GPS and magnet sensor for data recording where the old 305 did not, as @tshulthise states.

There have been long discussions in the Garmin Forums that the 705 was like the 305, but that a software update along the way changes that so that wheel magnet and GPS distances are integrated, but it is hard to see that item in the change log. I'm still skeptical, and Garmin has not weighed in on the discussion.


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## tshulthise (Apr 23, 2010)

Correction... I must have done something wrong. Its very accurate now with the cadence sensor on. Just noticed that I posted this a while back.


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## ericthepotter (Dec 6, 2007)

*500 map view*

I realize this thread has been dead for a month and a half but here is a link to a ride I did with the 500 where you can see some of the trail.

http://connect.garmin.com/activity/55521115

If you use satellite view and zoom all the way down you can get an idea where the sampling took place and how often it misses the trail. The trail I road is a 7 mile loop and the 500 shows about 5.9 miles to the end (ignore the last part of the map I forgot to turn it off and it recorded about a mile of me driving home). Since I don't feel like pulling it off my road bike I plan on getting a second speed/cadence sensor for my mtn bike to improve accuracy.


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## tshulthise (Apr 23, 2010)

It works great with the cadence sensor. Its not a big deal to install a cadence sensor.


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## 3034 (Apr 12, 2006)

mine works best with an edge 305.....

the edge 500' s accuracy is so bad, I keep hoping garmin will have 
an update to fix it. I loose lock all the time on the same trails the
edge 305 was rock solid on. the 500 is a real piece of Shet



tshulthise said:


> It works great with the cadence sensor. Its not a big deal to install a cadence sensor.[/QUOTE


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## tshulthise (Apr 23, 2010)

With the cadence sensor its very accurate plus you get all the benefits of a GPS and the Garmin Connect web interface. The cadence sensor is no big deal to use and takes care of all your concerns. Easy.


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## carbs79 (Sep 8, 2009)

Does any body know if you run 2 cad/speed sensors (1 on MTB,1 on road) with the 1 head unit, does it automaticaly pick the sensor up when you switch between bikes or will i have go into the settings and pair the sensor when i switch bikes?


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## slocaus (Jul 21, 2005)

carbs79 said:


> Does any body know if you run 2 cad/speed sensors (1 on MTB,1 on road) with the 1 head unit, does it automaticaly pick the sensor up when you switch between bikes or will i have go into the settings and pair the sensor when i switch bikes?


Set up two different bike profiles, enabling the sensors in each, and then pair each one when you have that bike profile active. When you switch bikes, switch profiles, and it will be done automagically.


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## tshulthise (Apr 23, 2010)

3034 said:


> I had the edge 305 for 3 years (broke)
> I currently have the edge 500
> all for mtn biking
> 
> ...


True only if you don't use the cadence sensor and wheel magnet. However, the 500 is very accurate with the wheel magnet since it supplements GPS dropouts with the wheel magnet info.


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## maxxim (Jul 18, 2005)

*Edge 500 now has 1 second recoding*

Many people requested the feature because of the poor accuracy on the trails and Garmin listened.

You need to update firmware to 2.7 or higher and change from smart data recording to one second data recoding located at Menu -> Settings -> Bike Settings -> Data Rec. -> Data Recording.


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