Any way to edit wheel size in a garmin file?

A buddy of mine and I did a HUGE ride today all on singletrack. My Garmin updated last night and I didn’t think anything of it until my mileage was WAY off today on a course I ride regularly. The update screwed up all of my wheel sizes on my sensors!
Is there any way I can get into that file and correct my wheel size? I’ve looked in Golden Cheetah, but can’t find it…

This is a shot in the dark and I’m not 100% if I’m getting this right, but if you strip out all the speed and distance data, would it then recalculate speed and distance based on your gps locations and timestamps?

You can use the above online tool to do it. Make a copy of your FIT file and see if it makes a difference…


  1. Go into the Tool section
  2. Select the Bike you are using on the ride ( That asumes you have set up for more than 1 bike, the Garmin allows lots of Different bikes setups)
    3 The 3rd one down below Bike weight, you can input the wheel size.

Not sure it will recalculate the work out you have already done.

I will have a look at one of my saved files and see if i can change it in a saved file.

Thanks. I ended up using Garmin’s tool to export the fit file as csv. I opened the csv in excel and found the distance data column. If you add two columns next to it you can then use a formula to add in a multiplier (ratio of correct wheel circ / incorrect wheel circ) to adjust the values. Then you have to past (values only) into the second column you created. Once that’s done delete the original column and the one with the formula in it and save the file.
Worked like a charm!
Now to do rollout tests on all my bikes today and input the sizes again.

Yes, Strava should be happy with a fit file that has no speed and distance data fields if it has a GPS track.