Garmin 955 Altitude Problems

I had similar problem as you can check in earlier post this week considering distance. I haven't had time to repeat the test, but I will tomorrow...probably.

It was off on the "peak" for 12m on 432m, calibrated, went down and back up - then it was off by 16m. Day earlier it was showing max altitude of 620m while I was at 1030m. I don't get it why it only relies on barometric pressure, not combined with GPS location to get the altitude right..and "it has maps" + preloaded route was used with correct altitude.

Well, I had f6 and 955. Now I own a 255.

All are having these issues. Maybe at least my 255. But only thing to lnow is that altimeter can not be working good on a watch obviously.

It works very well on my phones Orux maps for example. Usually it is inside a 5m bias.

I had another same run/walk today. At 432m today it showed 412m. Everytime less and less. I mentioned that to Kevin-Garmin.

Interesting thing is I calibrated the altitude at that point to 432, it wrote calibration completed, waited for couple of seconds, checked again - 411m after calibration.

It only showed the correct altitude after the second calibration. The distance with Smart system is within 10m, but less than last time.

Another run, another woe. 432m today, FR955 showed 409m. Grit X with factory problematic barometer showed 433m. Every run it shows 2 meters lesser than previous. Everytime calibrated.

Does anyone on 13.15 have wrong altitude measurements? I did not have such issues before 12.27. I will probably go over 1000m this weekend if no rain and see how much it will be wrong. 

If it is the same problem on 13.15 I think of sending it for repair/replacement. I don't know if it is hardware or firmware problem.

Now when I bought Garmin, Polar started to work correctly and showing the same distance as all systems on FR955 + correct altitude.

Did you choose altimeter mode and not baro in settings before the tests? Can you do the test with auto calibration set on off so we can see how the barometric sensor functions alone? You can also check barometric sensor functioning if you leave the watch on the desk for a day and track pressure changes compared to a nearby weather station which is calibrated regularly and much more accurate then the sensor inside the watch.

I hope I wrote my previous post understandable.I referred to settings which are in my fr 935 but I believe that they are the same as in 955.  My fr 935 altimeter was very unreliable so I always took an old suunto core with me in the mountains which is spot on in steady weather conditions.

Hi thanks for the reply. I have all on auto. On Altitude or Barometer:

Auto Cal. - ON

Sensor Mode - Auto

When I calibrate I select - Enter manually. I do it from the glances (long press light button) and selecting Altimeter. I will try to do some of those tests for weekend, but I was wondering if anyone had such problems on the beta firmware. I don't recall such issues before 12.27 as I mentioned.

Whatever configuration you use the Garmin altimeters do not work, I have 945 and it is a disaster even blocking it on the altimeter only (a little better than automatic), from the tests made by both me and other friends of the forum, the algorithm used grants too much importance when the temperature varies, in fact just staying above or under the blankets generates variations in height, crazy

Mine is on 12.27 - seems to be the latest software. 

But altimeter seems to work for me so far - but yet to test it rigorously, though I did it for a few hikes and it worked much better than auto. 

I always calibrate with GPS and it is usually pretty accurate based on elevation markers. Calibrating with DEM doesn't work for me - I get totally weird numbers even if I've got the relevant maps downloaded. 

Lastly if it's about the sensors being in the wrong place - totally agree that this is silly and hopefully Garmin can fix this going forward. 

What I don't understand though is that the watches are rated for swimming etc so technically the sensors (wherever located) are prone to exposure to water and stuff? This goes for all garmins of course but the constant exposure to sweat for the forerunners can't be good. 

According to the graphs, I think the problem is that if the sensor mode is set on auto, the watch is not quick enough for efficient switching between alti and baro mode and between each switch when we stop moving a few meters of elevation are lost. And if elevation is manually inserted before starting activity, GPS will not correlate elevation during activity. That's why the elevation count is lower than expected.