Forerunner 245 distance measurement really sucks

i have seme problem. My whifes F245 shows (during running) 15K after over 16,5K run activity on my F6xPro. Even Casio G-Shock shows 16,5K.

It was not first time becouse in Rome during the Marathon F245 stops tracking route after 36K, but distance was correct ...

I was written about this in topic on "Beta forum".

FR245, missing part of activity. - Community Discussion - Forerunner 245 Series - Garmin Forums

And nobody has aswered me ... Stange 

It was so also with previous firmware as I wrote here
https://forums.garmin.com/sports-fitness/running-multisport/f/forerunner-245-series/292555/why-my-forerunner-245-distance-measurement-are-really-bad

really bad Garming did'nt solve it

Pieri70 said:

What happens with this device?

Have you contacted Garmin Support? Maybe something with your device is not ok.

And sorry to ask, sure you waited, until you had a fix for GPS?

I had the FR 245 for more than two years and dozens of runs on my „home track“, which is 10,3 km according to Google maps. Usually my FR245 showed values between 10,28 and 10,38km, sometimes little less or little more. I never had more than 1% difference!

Yes I did and at that time they told me to completely reset the device and to use USB connection to reinstall firmware.

Then I got a surgery to my knee and didn't use my device for a long period.

Now I'm practicing sport again and the problem still exist.

My device is out of warranty.

Every time I wait until the top bar is green and I hear a beep.

Ok, very strange indeed. Such a big difference in distance must be some kind of bug or hardware problem.

Have you checked, if „3D distance“ for activity is activated? In other threads this was identified as source of errors - it should be set to „off“, then distance measurement will be more reliable and consistent.

Where is "3D distance", on device or on garmin connect website?

It is on the device, but not in general options, but in options for each activity type (e.g. running).

So Settings - Activities - … - … settings - 3D distance/ pace

I am not really sure if the 245 has this, as I have a 255 by now, but you should check.

All 3D settings should be „off“

Hello again,

after last beta update 12.51 distance was quite good (marathon 42,70K), pace measured all time, full track registered. I think it works ;) But is must be tested.

walk between buildings also registered without problems (not "straight line" - this is gaaaaaaaaaaaaaaarmin :) )