I’m a new Xert user and I ran into a power consistency issue between my indoor and outdoor rides. I use Xert for both, but with different power sources: indoors I use a Wahoo KICKR CORE 2, while outdoors I use Favero Assioma PRO MX-1 pedals.
Since the pedal power meter that generated some of my breakthroughs appeared to be reading higher than the trainer, I wanted to check whether both sources were on the same power scale.
In my case it turned out that the power meter pedals were reading about 6.2% higher than the Wahoo trainer.
I decided to write down the procedure I used, because I could not find a simple step-by-step protocol and had to make a few mistakes before getting useful results. Maybe it will help someone else. Also, feel free to point out any mistakes or suggest improvements.
Equipment used:
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Wahoo KICKR CORE 2
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Favero Assioma PRO MX-1 pedals, single-sided
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Xert EBC on smartphone
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Garmin bike computer
Goal:
Check whether the smart trainer and pedal power meter are on the same power scale. If not, estimate the offset needed to align them.
Procedure:
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Put the pedals on the trainer bike/frame.
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Set the correct crank length in the bike computer and/or pedal app. In my case, this meant checking the Garmin settings and the Favero Assioma app.
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In the Wahoo app, turn off ERG Mode Power Smoothing for a cleaner comparison.
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Create a short ERG workout in Xert. I used:
Warmup: 4 min at 50% TP
Test: 3 min sets at 62 / 74 / 86 / 95% TP each, with 45s rests at 50% TP in between.
I kept the test steady-state because I wanted it to be short and easy to repeat several times. My assumption was that steady blocks are better for estimating a simple scaling offset. Short hard efforts or sprints may be affected by ERG lag, trainer inertia, reporting differences, and changing L/R balance with a single-sided power meter. That said, I may still validate the final offset later with some harder intervals.
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Use Xert EBC to control the trainer and record trainer power.
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Use the Garmin bike computer in indoor mode to record pedal power. Garmin may try to control the trainer — do not let it.
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Do a calibration of the pedals before the test. My Garmin has that option, Favero app too.
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Start recording on Garmin first, then start the workout in Xert EBC.
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After the workout, stop pedalling, let both power readings drop to zero, then stop both recordings.
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In Xert Online, find the activity. If both files are grouped as duplicates, use the duplicate activity function to access both recordings.
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Download both FIT files from Xert.
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Compare the files using a tool such as Compare the Watts. Also I found that Chat GPT 5.5 (the paid, thinking version) did an good job comparing the fit files and suggesting the offset value.
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Calculate the ratio:
trainer average power / pedal average power
Example: if the trainer reads 160 W and the pedals read 172 W:
160 / 172 = 0.930
This would mean the pedals are reading about 7% high relative to the trainer, so a power adjustment of about -7% would align them to the trainer scale.
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Set the required power adjustment in the Favero app.
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Repeat the test until the two sources are close enough.
Caveat:
My Favero pedals have a power adjustment option, while my Wahoo trainer does not. Therefore, I adjusted the pedals to match the Wahoo scale. I understand that pedals and trainers measure power at different points in the drivetrain, so this is not necessarily about finding the “absolutely correct” power number. My goal was simply to make indoor and outdoor Xert data more consistent, so that breakthroughs from one source do not make workouts based on another source unrealistic.