Big discrepancy between FIT and GPX file total distance, and as displayed on Trip Computer

Has anyone else run into this?  My trip computer is giving me really bad calculated distances.  On a 10 mile walk, it told me I went 16 miles.  Downloading the FIT file, the FIT file has the bogus distance.  The GPX file had the correct distance.  Both have the same exact points, same track.  The trip computer displays the FIT calculation, which is clearly wrong.

I have contacted customer service about this three times and they keep telling me that they expect a difference between the FIT and GPX.  However, this is way off, there's no way I should be seeing a 6 mile difference over 10 miles (BTW I know the route and I know it's 10 miles, not 16).

I am really frustrated with the customer support.  They are not taking me seriously.

I'd appreciate anyone who has some ideas on this to share their thoughts.

Thank you. 

  • Hi the GPSMap 66s unit has sw version 7.20 their are know updates showing as available in Garmin express.

    All fine with gpx  just issue with .fit which has elevation issues.

    The original post mentioned that Garmin were aware and hoping to release a firmware fix in may , v7.20 was released in March, in the UK no new releases since then, kind regards

  • Hi, I have been in communicaiton with Garmin for a good while on this and they were working on fixing it.  They sent me a Beta version so I could test it and it did fix the distance problem but not the altitude problem.  I was told that they would be releasing an update in May but that didn't happen.  So I'm a little disappointed.  I haven't seen any update since v8.10 in the US.  I am about to start my thru hike so too bad the new release isn't out yet. 

  • Version 7.60 for 66S is here. I will test.

  • That's great thank you , do you have anything from Garmin that shows what this new version adds or fixes ? Thanks for looking into this 

  • Hi I know someone who has now tested v7.60 and they have advised their is still an issue with the elevation data in the .fit file , my unit still won't let me update past V7.20 firmware , hoepfully another firmware release asap will sort this issue 

  • For 66S not fixed in release 7.60. It is not listed as one of the fixes. But it was worth checking.

    Same symptom:
    FIT file has exaggerated distance and climb. GPX file correct.
    Open GPX file in basecamp - delete a single point. (Last one for example) - Total Distance and climb do not change.
    Open FIT file in basecamp - delete a single point. (Last one for example) - Total Distance and climb now match GPX. 

  • Just FYI, the FIT file contains gyroscope information. That's why the file format that downloads if you run on a treadmill is FIT, after clicking "download original." It is possible to have an arm swing, while running, that is both faster and unevenly proportional to one's cadence (stride). So, one's FIT file is showing mileage based on your arm's swing, as interpreted by the gyroscope, like in a treadmill run, but the GPS is tracking a different distance in mileage based on GPS waypoint locations. My friends and I used to joke around and swing our arms much more and ridiculously faster than our natural running cadence, to see how big a difference in mileage it would report. We also used to get on the treadmill and swing our arms ridiculously fast while running and the FIT file would say we ran a mile in 3.01 minutes. (hahaha)

  • Interesting. But that is not what is going on here. If this were the case then you would see consistent discrepancy. The issue appears to be with the saved file. If you edit the file and remove a single point the totals are then correct. This is the same for a 3km or20km hike. So the issue is with the way the whole file is saved and the way the distance and height changes are calculated. Remove one point and basecamp then calculates correctly.

  • Resolved with current Firmware just released???