Fenix 6X with wrong elevation data and spikes on altimeter profile - Sign here if you have the same

Hello everyone, I’m reporting my very bad experience with Garmin. I bought one of the premium products on the market and a strong brand, looking for highly reliable basic metrics, GPS and Barometer Altitude. I’m a long trail runner and these data are very important.

But in 1 year, I was completely disillusioned from the Fenix 6X Sapphire not able to measure for me the altitude gain. I wasted a lot of time with Garmin, I called, I wrote to support and beta testing team, I had 2 replacements without any explanation, but the problem is still not resolved on the 3rd device and several Firmware.

I have hard times to accept to not have an official answer from Garmin included no mentions on firmware fixes, apart replacements without any explanation. This make my suspicious of a design flaw (on barometer sensors and holes positioning) that Garmin doesn’t want to acknowledge, but this is just a personal speculation.

Problem:

After 20/25 minutes of running, the elevation profile starts to present random peaks and spikes in altitude that finally results in completely wrong elevation gain. Randomly I have hundreds of meters of altitude gain in flat runs of 10 / 12km. We are not talking about errors of "a few meters" but about measurements that on average are more than 3 times, with more than 250% error!

The elevation profiles are ALL OF THE SAME TYPE where the problem is appearing after 20/25 minutes.

It is not a problem of using the watch ... I have been running both trail running and road for 10 years, never had such problems with Suunto (Ambit 2, Ambit 3 Peack, Sparta, Suunto 9 Baro), only with Garmin Fenix ​​6X Sapphire.

I went through several tests:

  1. I tested 3 Garmin Fenix 6X Pro (my first one and the 2 replacements)
  2. I Test the various types of calibration (manual, at start-up, continued). Enabling, disabling the maps.
  3. It's not a GPS coverage problem, I run in open spaces and clear skies
  4. I have hard reset clock
  5. I have tested the various firmware releases over the months and the problem has always arisen

 The problem does not occur:

  1. Wearing the watch on the right wrist (where the barometer holes are NOT frontal to the running direction so no direct air flow that may push swear in)
  2. Using a wristband on the right of the watch, protecting the barometer holes from sweat
  3. Using a cover (where the barometer holes are protected)
  4. Wearing the watch on the belt
  5. In easy activities, such as walking

These items, combined with the fact that the problem occurs after 20/25 minutes, may indicating that the cause is the sweat entering on the barometer holes with the swing of the arms and the front air running, thus disturbing the sensor. Not sure why this is not happening to everyone, maybe it could be depending by the individual sweating level and\or different physiology of the liquid (who knows? The PH, …).

Since in my several calls with the support they told me they never had complaints for altimeter problems I invite whoever have the same to reply indicating “I have the same” and I compile in this post the list of the customers affected

Only 2 examples...find many in other posts on the forum. All are similar, some better, some worst but always wrong.

     

Users affected:

  1. Paolo Costantini
  2. acajic14
  3. eezytiger

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  • I read somewhere else that some Instinct have the same issue, which seems to be solved with their latest beta...

  • Yes, but unfortunately there is no feedback about that yet. Let's wait and see :) 

    • Fixed rare issue where elevation would jump after starting an activity.
    • Improved the accuracy and reliability of elevation data during activities.
  • I had the exact same issue with my Fenix 6X Pro. I'd start getting those spikes after 20-30 min. After some trouble shooting with a Garmin support team member, we found it to be caused by sweat getting into the altimeter port. The 6X's altimeter is extremely sensitive and the ports are in a bad location on the watch and sweat easily gets into them. I think previous models of the Fenix had a more raised back which kept the ports a little bit off the skin. The Fenix is lower profile and now sweat is an issue. As long as I'm wearing a wrist band to absorb sweat the altimeter works fine. 

  • Why doesn’t water cause the same problem? Surely swimming creates much more opportunity for water ingress? 

    How were you able to troubleshoot this issue so conclusively over the phone when it couldn’t be resolved from the returned watches?

    How do you suppose the sweat gets into the holes? Do you have so much sweat on the back of your hands that it flows off in sufficient quantities to block the ports? 

  • I know it seems hard to believe and thought it unlikely when the Garmin rep suggested it. I gave him the benefit of the doubt though and when I noticed the spikes happening in real time on a run last week I checked the ports. Surprisingly there was sweat in there. I cleared the openings with a puff of air and saw the elevation readings immediately stop fluctuating.   
    I think the issue is how close that lower port is to the skin. If you sweat a lot, as I do (I live in a warm and humid climate), it seems to easily flow into that lower port. Part of the issue may also just be the size of the port openings. The openings on previous Fenix models were wider. Here is a Fenix 5 for comparison:


    Maybe some capillary action going on with the 6X ports?? This is a problem I never had with my 935. The ports are in a much smarter location on that watch. 

  • Why doesn’t water cause the same problem? Surely swimming creates much more opportunity for water ingress? 

    Is altimeter function useful for swimming? What sort of gradients do experience when you swim? Maybe the altimeter is locked for swimming, just as it should be, but wasn't in the past, for indoor cycling.

    A couple of days ago I showered with the watch. Whilst drying off I received a storm warning alert. There was no storm. But I expect the water in the watch created a seal and its own weight/inertia/momentum created the impression of extreme pressure changes, exactly as we see with these spiky elevation graphs.

    I would say that water blocked ports and pumping arms are a justified explanation for this undesirable behaviour.

  • What sort of gradients do experience when you swim?

    Off-topic.

    You might not be aware, but the old phil here, he can easily do 10% gradients when swimming. With his hands tied behind his back. Can also swim straight up, if needed. In thin air too. Walking on water is another favorite pastime of his. Even when it is not frozen. Does not need the GPS in his Fenix, as he can navigate by the polar star in the southern hemisphere in broad daylight and blindfolded. Always tells his Fenix and lab equipment what his correct heartrate is. Chuck Norris hides away and whimpers when he is nearby.

    End off-topic.

    Have a nice day.

  • I had similar problems in last summer. I was following the relevant topics here as well but I concluded that it was a design problem.

    After spending a lot of time on documenting/reproducing/experimenting on the issues I got tired of it.
    I vote for the sweat, which may cause spikes when it is convering the baro input as a thin film or randomly blocking the barometer holes or only part of them.

    Usually it took 25-40 minutes till the issue emerged. I got zero issue since October.

    Here are some examples, I cut them from Strava, they are visualizing much better than Garmin Connect.

    Example #1

    Flat segment on an 5km island loop:

    Good. At 8.1km it starts go crazy.

    Good elevation until 8,1km

    Baaaad.

    Same segment, bad elevation in the next loop

    Example #2

    Loops on a 300m track. Good ones (I've seen better elevations but it is within meters, it could be a windy day)

    300m loop good elevation (let's say - windy day)

    At approximately 40 minutes fluctuation is over 15meters.

    Bad elevation. Sweat?

    Another one.

    Nice start (flat road, then a bridge at 5th km then flat again until 6th km from where it was going crazy.

    Bad From km 6

    After this run I investigated the baro holes and there were sweat droplets around. Those bright dots are sweat drops, glaring in the sun.

    I even can see the culprit: a hair that can transport sweat or water to the holes. But I'm sure that fluid can get then without the hairs. I had problems in rain.

    baro holes

  • Is altimeter function useful for swimming?

    Hadn’t considered the altimeter might be disabled for swimming so that makes sense.

    Are we sure that lower port is for the barometer? My understanding is that it’s only the two ports higher up. Assuming the ports on the F6 Pro are the same it looks like that lower opening is for inserting a tool to lever off the back when the screws are removed. If it is a barometer port it is very poorly placed but then I can accept the possibility that sweat might block the port. However, so can rain, dirt, dust etc and we would expect to see many more instances of this problem instead of just a few.

    I am more than willing to concede the possibility of sweat causing the spikes but that is not the same as seeing hard evidence that it does. 

  • F3HR used to generate a very creative altitude graph for indoor cycling.

    With the 6X it is not even possible to display this nonsense data.