How to download and edit a Hammerhead Karoo FIT file

The Karoo records every ride as a .fit file and syncs it to the Hammerhead Dashboard, which can send it on to Strava, TrainingPeaks, Komoot and others. To cut a section or fix a bad stretch of data, download the file, fix it, and upload the clean version.

Step 1: get the file

From the Dashboard (the easy way, once the ride has synced):

1. Sign in to the Hammerhead Dashboard and select Rides in the sidebar.
2. Click the ... next to the ride.
3. Choose Download FIT, then Save.

Straight off the Karoo over USB (for a ride that never synced). Hammerhead gives these steps for the Karoo and Karoo 2:

1. Turn on Developer Options on the Karoo, then switch on USB Debugging there.
2. Connect it to your computer with a USB-C data cable (a charge-only cable won't show any files).
3. On the Karoo, under Developer Options, tap Select USB configuration and pick MTP, even if it's already selected.
4. Open the Karoo's storage. On Windows it shows up in File Explorer under Internal Storage. On a Mac, Hammerhead's steps use the Android File Transfer app.
5. Open the FitFiles folder and copy the ride to your computer.

From Strava: open the activity on the Strava website, three-dot menu, Export Original.

Step 2: fix it

Open the file in FIT File Editor. The route is on the map, with speed, heart rate, power, cadence, and elevation on the timeline underneath.

• A section in the middle. A café stop with the unit still recording, a car ride back after a mechanical, a stretch where the GPS jumped. Drag across it and press Cut. Distance, time, and averages are recalculated. See crop a FIT file.
• Two files for one ride. The Karoo restarted or you started a new ride by mistake. Open the first file, press the plus button, and add the second. The merge guide explains how the gap is handled.
• Power or heart rate spikes. Select the stretch and cap, smooth, or fill it with the fix tool. The heart rate spike guide covers which to pick.
• GPS drift. Smooth a jumpy stretch or drag a stray point back. See the GPS drift guide.
• Heart rate from a watch. If the strap didn't pair but your watch recorded heart rate, open the Karoo file and add the watch's file. Channels the Karoo file is missing are filled in over the time they overlap. See combine two devices.
• Wrong sport or wrong time. Set the sport in the details panel (change the sport), or shift the start time (time tool).

Press Export to save the edited .fit. The file stays in your browser the whole time.

Step 3: upload it

Delete the old copy on each platform first, then upload the edited file. Platforms reject a file that overlaps an activity they already have. The duplicate activity guide has the order for Strava and Garmin Connect.

The Dashboard's Sync to... option sends the ride it already has, not your edited copy, so upload the edited file on each platform's own website. Hammerhead's import help covers workouts and routes, not recorded rides, so plan on the original staying in the Dashboard.

Worth knowing

• Keep the original. Hold on to the downloaded file until the edited one is in place everywhere you want it.
• A ride that won't open. A Karoo that froze or lost power mid-ride can leave a damaged file. The editor recovers what it can; see repair a FIT file.