GPS Watch Faults

Dear All,

I am using Smart Watch Xiaomi Amazfit Stratos 2.

It measures my distances wrong. Today I swam a course that I know its distance (3km), but the watch measured 2.5km, also the route is nonsense, see the below photo:
https://drive.google.com/file/d/1zk4ESE9jfQn5ZRxyqtIkta8mC9zoFafA/view?usp=sharing
(When I analyze my swim I can only say that the watch understands that I am fed up with Istanbul and tooks me to Antalya      )

Also on Saturday I swam 5.5km(the distance I know) the watch measured it as 4.5km. In our group there were guys having suunto, fenix3, fenix5 and garmin 935xt. Their watches also measured differently but there were no remarkable difference between them, they measured 5.62, 5,45, 5.56 which were quite acceptable due to their zigzaggings in the water.

After I watched the below GPS watch comparisons I do not rely on any watch from now on:
https://www.youtube.com/watch?v=W829SSge2Do
https://www.youtube.com/watch?v=I_p47c4d2Ug
https://www.youtube.com/watch?v=4HsSFBqXUQM

The best solution for me is counting my strokes(determining the avg strokes per length in the pool then counting the strokes in the OW, for example 450 strokes as 500m with 80SPM) as I did before and just measuring the time with a basic 5$ stopwatch.

Any recommendations?

I've never used a GPS watch but I hear some people find them very unreliable unless put under their swim cap or in a tow-float! (GPS doesn't work too well underwater)

I have a lap-counting watch, but it can also estimate distance in open water based on stroke length. You put in how many metres you average per full stroke cycle, and it calculates your distance. Obviously results can be variable depending on currents etc. It's this one: PoolMatePlus.

Dear Mike,

I also have been counting my strokes fro determinig the distance for almost 20+ years in my open water career, this is the best solution, I agree and can say that the GPS watches are nonsense.

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However, today my watch measured the right distance with 2 different modes (triathlon and open water).

Open Water Mode:
https://drive.google.com/open?id=19drfHonkNc9mOjXFq3zy1s9Q1sh_HHta

Triathlon Mode:
https://drive.google.com/open?id=1rOhJVi5_fR8AU0lce6PH6oC4b_cudYYc

I am sharing my findings:
You need to select open water and start it immediately without waiting for the GPS to connect, in this case it measures correctly. As explained in the instruction manual, if you wait for the GPS to connect, theGPSs can detect an incorrect location in the water, and the wrong location is irrelevant to the course you are swimming in.

My comments after I swam and tested Xiaomi Stratos 2 watch in 3.5 months by swimming 310 km:

If you select the exercise type as "swimming pool", the measurement is sensitive, it shows all the data and it is very comfortable to use with one button, it doesn't bother while swimming because it is light and easy to see the screen (big puntos).

If you are going to swim in the open water, you need to choose triathlon or open water, you must press the start button as soon as you start without waiting for the watch to connect to the GPS.

Watch's glass has never been scratched even while I am tying my motocycle by the chain where sharp metal materials hit the watch's screen many times, there is not even a slightest scratch on its screen.

As a result; If my current mind, I would continue with a classic 10$ simple stopwatch since I already know the distance according to my stroke count. But if you want to have an affordable GPS watch, you can buy it for 1/3 price of the Garmins.

Yesterday I sold my Xiaomi Stratos 2 Smart Watch to my friend, I am continuing my workouts by my old simple digital stop watch. As I have been doing for years I set its timer to give beep on each minute and counting my strokes. Trying to hold my SPM above 75 with finis agility paddles. Without paddles I can manage 80+ SPM.

Today morning I swam 2400m by holding 75 SPM in flat sea (30:40, 1:17 average pace).