Fenix 7X: Altimeter issue since 10.43

I am using Fenix 7x SS and have the elevation problem bugging me since the last firmware (10.38 may be)

I mostly trail run and elevation is a very important metric for me.  Ever since upgrading to 10.38(?) and the current version of 10.43, i noticed the altimeter sometimes drops and bounces back crazily. For example, i am walking steadily at around 500m, the altimeter will suddenly drop to 450m, and in matter of 10 seconds or so, it will bounce back to 500m. Accumulating multiple sudden drops and bounces of altimeter, in total the elevation and descent will be massively exaggerated.

In a 50km trail run I did in last week, the known elevation and descent of the route is 3300-3600m, and thats also what I got with Fenix 7x in previous firmware. But i got 5500 m of elevation last week.  Hope anyone could look into the issue.

So far I’ve gone through 1x Fenix 7S solar and 2x Fenix 7 solars in the last 3months, all with similar issues.

Total Ascent seems to over-read by anything between 15 and 20%. This when compared to Edge 520 and Forerunner 735XT units which both show almost identical TA readings on the same route on the same day. 

I always make sure to calibrate the Fenix before each activity. I’ve tried wearing the watch on different wrists, toggled between Barometer and Altimeter only settings, performed hard and soft resets, switched between every second and smart data recording, etc, etc. All to no avail. 

Really hope someone has a solution or even better yet, does GARMIN have an explanation because getting feedback from them in South Africa is like drawing blood from a stone. 

7063622 said:

So far I’ve gone through 1x Fenix 7S solar and 2x Fenix 7 solars in the last 3months, all with similar issues.

Total Ascent seems to over-read by anything between 15 and 20%. This when compared to Edge 520 and Forerunner 735XT units which both show almost identical TA readings on the same route on the same day. 

I have struggled with inaccurate / inconsistent altitude data every since I switched from my Fenix 3HR to the Enduro that eventually led to the Fenix 7x SS. Other than poor battery performance, the F3HR had no issues with total ascent accuracy which was the reason I got the Enduro. After many months of testing, I concluded that the issue you're experiencing has to do with the location of the barometer opening which doesn't affect Forerunner models. I trail run with friends and we have Enduro, Fenix and Forerunner models in the group and pretty much the only ones who do not experience such issues are the ones with Forerunner. 

The ones with Enduro and Fenix models had wild Total Ascent data between each other because of factors such as individual sweat rate. Here's what fixed the problem for us and we're seeing very small differences in total ascent data between watches—around 3 to 10m https://twitter.com/JanShim/status/1602209468938260480

Same thing happened when I went road cycling with a friend who wore an Enduro and mine a F7x SS. That day, he forgot to wrap a Buff and when we finished our ride, his Total Ascent was much higher. The next time we rode together, both with Buff, the resulting data was as expected. It's not about left hand, right hand or even calibration before activity. My F7x is running the latest software and I have not experienced altitude issues ever since I started running/riding with a Buff.

Hi Jan,

Thanks so much for the response - really appreciate it. 

I’ll give this a try and see what it yields. I tell you though, if this does solve the problem, I’m certainly going to return the device as there’s no way I’m spending that kind of money on a piece of equipment that needs a workaround like that. 

Garmin really dropped the ball big time on this one then. 

Thanks again!

Apologies - I meant to ask, what Forerunner model does your friend have?

Is it a newer gen unit also equipped with the open barometer ports to the right? Or is it an older version? 

I’d imagine a newer gen unit would have the same issues as the F7 and Enduro?

7063622 said:

I meant to ask, what Forerunner model does your friend have?

Is it a newer gen unit also equipped with the open barometer ports to the right? Or is it an older version? 

They're the older model. The current gen Forerunner has the barometer ports on the right side but are spaced apart with each opening parked next to the Start/Stop and Lap buttons respectively. Not sure what difference if any this makes or whether they're also susceptible to the same problems. 

The problem when it happened on the Enduro drove me mad. I did everything from religiously calibrating the watch using DEM and Manually using altitude data, even messed with Barometer settings, tried Baro/Altimater watch mode, nothing worked. Then one day I started training for a trail race with gloves on (to handle poles). The glove on the left hand stopped the pools of sweat flowing from the back of my hand onto the watch and past it ... and the elevation data didn't go crazy that day. Days, weeks passed running with just a glove and data was consistent. Race day came (was nervous as hell, not about the race but whether I would finish with silly total ascent data) I completed the 30.5km/2075m (official) event having recorded 29.8km/2029m. I couldn't be happier!

That was in September. Over time I got tired of the glove and switched to using a Buff and discovered an added advantage over the glove. The glove would only stop sweat but still leaves the baro openings exposed to drizzles/fast moving air when you're running fast (similar condition to cycling against headwinds etc). I have found that with the glove, total ascent would occasionally creep up when I run compared to my friends who didn't but we all still finished at the same spot. This is where the Buff comes in ... stops inteference from sweat/rain/wind. 

Having said this, my Fenix 3HR from 2016 has the same barometer opening design and apart from dunking the watch into water (such as when you cannot resist the urge to jump into a lake on a hot day), almost nothing would create a problem for total elevation gain accuracy. Somehow Garmin got some things right with that model.

Oh BTW, I set my F7x Altimeter Auto Cal to Nightly and Sensor Mode to Altimeter Only.

MiniYoshi

I've owned two Enduros before the F7x. The first Enduro reported wild Total Ascent data and nothing I did would make it function properly. A 32km trail run with an expected Total Ascent of 2800m the Enduro recorded 600m higher. This went on for a good six months while I was in communication with Garmin email support. Things got increasingly frustrating to the point I was so drained. Eventually, the watch was sent to Garmin Taiwan and they found the barometer to be defective and shipped me a replacement.

Hi Jan,

Did the replacement Enduro sort the issue out without the need for the Buff work-around?

I always cycle with gloves so I didn't think sweat issue would be such an influence. Added to this I have tried with the watch on my right wrist where the ports would be on the opposite side to the direct wind and have (supposedly) less sweat exposure. This made no difference. 

I went out for a short MTB ride with my wife today - her using my Edge 520 and me on the F7 Solar. I tried your suggestion of covering the ports, only I didn't use a Buff (too much material for a 32deg day ), but rather a sweat band and it seemed to yield a much better result (still not to my satisfaction though). We did a 33km ride with 458m (F7) vs a 438m (Edge520) total ascent readings. This was the lowest deficit I've managed to record thus far - the last ride we did with similar distance and ascents, the F7 over-read by 70m. 

I really do not know what to do. As you mentioned, its incredibly exhausting to continuously have to fight with a device that you don't trust. If the Total Ascent is that inaccurate how can the rest of the metrics yield any level of accuracy. 

It really is inexcusable (in my humble opinion) that such a top tier device can deliver anything but the most accurate data available across all metrics. But instead it seems to fall ridiculously short of older gen devices unless you wear a Buff/Sweat-Band over the ports. Maybe Garmin should supply a complimentary Buff with each Enduro/Fenix/Epix sold

Much appreciate hearing your experiences though - at least I know I'm not going mad!

7063622 said:

Did the replacement Enduro sort the issue out without the need for the Buff work-around?

The replacement Enduro has a proper working barometer but suffers the same drifts when used without a Buff. Having to put a piece on each time I ride or trail run is completely Ok—we have many—as long it means consistent and accurate data. As far as I'm concerned, my fight is over and I've found the solution. Coros on the other hand has their barometer opening on the left side so if worn on the left hand, doesn't experience this. Not sure if there's issue if worn on the right hand.

Regarding your F7 vs Edge differences, those two are known to have notable Total Ascent differences. I don't know anyone who has both devices has seen matching data. I once rode a 30km distance with my Fenix 3HR worn on the left wrist (no Buff) while the F7x is mounted on the handlebar. There was a fair bit of headwind I had to deal with that afternoon, surprisingly the F7x recorded lower Total Ascent than the F3HR — the F7x has never recorded lower Total Ascent numbers than the F3HR before.

Ok - it would seem I need to wrap my head around either using a Buff or returning the unit and trying something like the Forerunner 955 and see if there's any difference there. 

Would be a pity to have to go that route though as I really prefer the look and sturdy construction of the Fenix over the "cheap" and seemingly flimsy feel of the Forerunner. 

Anyhow, I'll keep you posted. 

May you have many happy and safe miles bud!