Garmin acting funky...

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lalahsghost
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by lalahsghost

I don't typically do hill repeats, but today I decided to. First time, 480ft/148m. Accurate, since it was 0.7mi/1.12 km. Average elevation gain was close to 8%, but spiked to 12-15% once or twice.

Okay, I zoom down the hill to ride back up.

On the second time, the Garmin Edge 500 is displaying -1% to 3% grade, and an elevation increase of 170ft/52m in 0.7mi/1.12km.

Yikes, well, that's odd and not the same. My times were off from each other by less than 30 seconds comparing the two climbs, so it wasn't like my tempo was tricking the computer.

Later in the ride, I was cruising along at a fair speed, considering basketball sized potholes all over the place, and the accompanying gravel... Normally about 18-19mph, and this is pretty accurate, being in my 48x17. I had to check my gearing, because my garmin was saying I was going 11-13mph/ 17-20kph. Grrr...

Could it have been satellite/environmental issues? The ride was occurring 30 minutes after a decent day's rain, but since December 2009 (when I got the Garmin 500), I've never seen such wonky data...

Ugh. Any clues?

etownfwd
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by etownfwd

First, I'd check to make sure that you have the latest firmware for your garmin. If not, see if an update fixes it. Sometimes I've had goofy data show up on my edge in-the-moment, but the info shows up slightly differently when I download it into connect. My experiences have been with heart rate issues, mostly, but I don't see why that couldn't happen with speed too?? :noidea:

If I don't run the speed/cadence sensor and you are just using the GPS to determine your speed, then from what I've read on the garmin forums, it's possible that environmental issues like cloud cover or precipitation might affect your data.

If you are still getting batsh1t data points, then check over on the garmin forums (https://forums.garmin.com/forumdisplay.php?f=20) for some fixes. Some of the resourceful folks over there have come up with several ways to "fix" wacky data points in the .tcx files.

Good luck and I hope you find a fix!

-efwd

by Weenie


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astranoc
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by astranoc

I think regardless of the speed/cadence sensor the unit always take the speed from the satellite. At least that was the case with 705, I am not so sure if 500 is any different.

artray
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by artray

If your Garmin is acting funky you obviously need to , " Take it to the bridge , good god get down "
Could not resist :) sorry .

stiffee69er
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by stiffee69er

I blame Vaughters

lalahsghost
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by lalahsghost

I think I found my problem - Water.

New PC7 style mount exposes the bottom side to water flung up by the front tire. This clogged the little "beep" speaker hole. I'd like to blame this as the culprit, but I'm also taking your guys' considerations!

(Totally JV's fault. I blame the turtleneck sweaters too.)

Oh, totally forgot; here's the link to a recent example: http://app.strava.com/activities/869886 ... eated=true
Last edited by lalahsghost on Thu May 17, 2012 4:34 am, edited 1 time in total.

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Liggero
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by Liggero

altitude, and gradient based on altitude diference, are always inacurate. I would be extremely surprised if, after repeating the same hill climbing twice, you get the same results, that wouldbe astonishing, it's extremely normal to have wrong data related to altitude stuff. This happens in my garmin 500, on polar, etc, etc... always. altitude sensor are very sensible to air pressure, and are very unreliable.
Happy Trails !!!

Murphs
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by Murphs

astranoc wrote:I think regardless of the speed/cadence sensor the unit always take the speed from the satellite. At least that was the case with 705, I am not so sure if 500 is any different.


Not true for the 500, mine works on rollers warming up for crits.

durkonion
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by durkonion

lalahsghost wrote:I think I found my problem - Water.

New PC7 style mount exposes the bottom side to water flung up by the front tire. This clogged the little "beep" speaker hole. I'd like to blame this as the culprit, but I'm also taking your guys' considerations!

(Totally JV's fault. I blame the turtleneck sweaters too.)

Oh, totally forgot; here's the link to a recent example: http://app.strava.com/activities/869886 ... eated=true" onclick="window.open(this.href);return false;

The 500 gets it's elevation reading by sensing the air pressure and that "speaker hole" is for the barometric altimeter, I believe. Uncover it and your elevation should be correct.

I'm not sure about the speed though. Do you have a speed sensor on there? Maybe the magnet was just far enough away that it was missing it every once in a while?

jvanv8
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by jvanv8

Yup, when it rains the elevation data is almost useless. This is pretty well known I think.
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astranoc
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by astranoc

Murphs wrote:
Not true for the 500, mine works on rollers warming up for crits.

Being static or without a locked gps singal locked yeah, I am talking about normal road riding. The ideal would be for one to correct the other all the time, but I doubt that the garmins are that smart.

durkonion
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by durkonion

Nope, the 500 will use the speed/cadence sensor for speed/distance if it is connected instead of GPS. The 305/705 used GPS until the signal quality dropped like you said, however.

OP, is your wheel size set to Auto? I hear that can cause problems as well.

lalahsghost
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by lalahsghost

durkonion wrote:Nope, the 500 will use the speed/cadence sensor for speed/distance if it is connected instead of GPS. The 305/705 used GPS until the signal quality dropped like you said, however.

OP, is your wheel size set to Auto? I hear that can cause problems as well.


I'll have to check - Thanks for the suggestion!

Murphs
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by Murphs

astranoc wrote:
Murphs wrote:
Not true for the 500, mine works on rollers warming up for crits.

Being static or without a locked gps singal locked yeah, I am talking about normal road riding. The ideal would be for one to correct the other all the time, but I doubt that the garmins are that smart.


No. If there is a speed sensor present, it uses the speed sensor.

by Weenie


timzcat
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by timzcat

ON the 800 and pressumably the 500, if you set the wheel size to auto it will use GPS data in comparison to wheel speed to determine wheel size and then use the speed/cadence for speed from then on.

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