Garmin AVG Power

I have a new power meter on my MTB, (Stages XT dual sided) and recorded some rides with it now.
I love having the power data when i’m on my MTB but the data between Garmin and TR/Strava/others isn’t the same. (recorded on a Edge 530)
The AVG power and thereby the NP, TSS, IF and KCAL’s are different between the platforms.
This is my ride from yesterday on different platforms:

Strava:
MTB sb013 met Niels Inc koprol | Ride | Strava

Garmin:
Garmin Connect

TR:
MTB sb013 met Niels Inc koprol by sasha1103 at Sunday, Mar 07 2021 - TrainerRoad

Garmin Connect give me an AVG of 256 and the others reported a average of 234/235.

Looked at this with an TR engineer (great help as always!!), and they noticed that the FIT file contains more data that TR/Strava does take into account and Garmin does not.

FIT:

I’ve created an export of the record that contains 5852 rows, i’m getting the avg power of 256, but including all the other records i’m getting the average of 234/235.

I have submitted a ticket to Garmin but maybe someone here knows why Garmin isn’t including all the data to get to the Average/NP etc. Kind of frustrating not to know what is the “real” data here.

Settings from my Garmin:
Auto pause on
Include 0’s in power = on
Include 0’s in cadans = off

Turn autopause off.

3 Likes

Did you set the Garmin to record data every 1 second, or is it set to Smart Recording?

It is set to record every 1 second.

  • turn off auto pause
  • record at 1 second intervals
1 Like

I’ve created a smaller test yesterday and still having the same issue with Auto pause off and with 1 second recording (setting was always on 1 second recording).

Evening Ride by sasha1103 at Monday, Mar 08 2021 - TrainerRoad

164 watt average by Garmin
155 watt average by TR

I checked my outdoor MTB ride from Sunday and the average power in Garmin and Strava was 171, the power in TR was 171.

I use an old Edge 820

Is your weight and FTP exactly the same across all devices and platforms? I know it shouldn’t change the power reading, but I’d check those too.

1 Like

Yepp everything is the same.

@GPLama & @dcrainmaker
Have you guys ever seen this?

Interesting. FIT File Explorer is a handy tool for digging around FIT file with.

Out of interest:

Weekend 70km ride: 206W Strava / 207W TR / 209W Garmin Connect.
Weekend 48km ride: 172W across all three.

Went digging and i can see that Garmin isn’t including all the data sets when calculating the averages. But cant find a explanation/reason why this is happening. If i include all the timestamp’s into a single file. The averages are the same across the board. But GC isnt doing this… UGH!

@GPLama
Think we’ve found the answer to this problem.
https://forums.garmin.com/sports-fitness/cycling/f/edge-1030-plus/258340/incorrect-average-lap-power/1234425
“So this gets a little complicated, but the difference is due to a couple of things going on. One is that there are radio outages that are causing some of the records to be back filled. The second is that the tools you are using to process the data are using the power values assigned to each record and are not using the accumulated power values. Using the accumulated power values is the better approach. Because of this the tools are subject to how the dropped messages are being backed filled.”

So if there is a missing data point, Garmin know’s this because of the accumulated power values and corrects this in the averages. TR and other platforms only look at the raw power data without taking into account the accumulated power values. So it’s actually Garmin who knows "best’.

3 Likes

now that is a good bit of information to know! Thx!