Garmin reporting higher max power than TrainerRoad

Hi all,

I’ve recently started using a Favero Assioma Duo power meter with my Kickr Core and using TR Powermatch. In my first workout with this set up and just to ensure everything was consistent, I also had my Garmin 520 Plus recording the data from the Assiomas. Both the Garmin and TR were set to showing 10 second power.

Overall the average and normalised power numbers reported were the same (within less than 1%), however in terms of maximum power there was a big discrepancy of around 20% difference (319w on TR, 397w on the Garmin).

I would have through that as they are both measuring data from the same power meter the data would be identical. Has anyone else experienced discrepancies between TR and Garmins and can anyone shed any light on the reason and what I can do about it? 20% difference just can’t be right.


Boy lots of things.

First off if I ride outside and look at max on Garmin it’s always higher than Strava. There is some smoothing and I suspect the max on your head unit is absolute max measured where what you see on apps is max measured over 2-3s.

For your specific scenario I think there are issues with multiple units reading the same pm at the same time. The pm takes multiple measurements per second but the device can only record 1 point per second

So your Garmin might grab, display, and record power from 0:00:01.3 and tr from 0:00:01.45 and that could be the cause.

While 10s power might be displayed on the head unit, it will be recorded at 1s intervals in the .fit file (and post ride analysis).

And when you are talking sprint and 1s power, timing differences between different devices can be huge - at 90 rpm, one device might capture 2 pedal downstrokes, while the other device only captured 1. As you increase the timespan to 5s, 10s, etc power, timing differences smooth themselves out.


Thank you both for the excellent explanations - that makes perfect sense.

So it’s not an issue with the equipment being at fault, just a matter of how they capture data at different times.

I guess that means I can take the highest power number that is captured out of the two of them as the ‘correct’ one then, as that will be the highest power recorded in that workout, it’s just that only one of the devices was recording at the specific moment that it was made, right?

Thanks again!