I finalized my testing of three power meters. It took place from 16.12.2025 until 06.01.2026. All screens and readings of power were made on
https://compare-the-watts.com/. All files you can find here -
https://drive.google.com/drive/folders/1zK7ZtPF-K969JV58sm26zGjgVzL1gek8?usp=sharing. Some photo examples I attached in the post. I will add some videos into the google drive, from rides and showing the calibration etc. Comparison is also on Facebook group -
https://www.facebook.com/groups/975602387895509/?ref=share.
The tests and all workouts were recorded on: Garmin Fenix 8, Huawei Mate tablet and Bryton S810. The following devices have been compared:
1. Favero Assioma Duo, used since 2021 (4.5 years)
2. Elite Justo, used since 2023 (almost 3 years)
3. Xcadey gen 2 easton 110 BCD (almost new)
Before every ride sources 1 and 3 were calibrated as Elite Justo is self-calibrated device, however, two times it was also calibrated and before all tests. The firmware for all devices has been updated, and it is the newest possible. All the data is on my google drive including all original fit files for all dates. Unfortunately, several times I had some issues, it was not related to connection or to any power source but the recording device ( I believe). Sometimes it was due to changing windows on my tablet and then My Whoosh device turned off the training, or I wanted to change recording device, and switch to another source.
During the testing period so for full three weeks which include many different workouts all sources showed rather consistent results, and the results were not identical of course. However, some unexpected episodes also happened, which I describe below:
1. For each workout, for each day you can find fit file;
2. For each workout you can find general screen and some detailed comparisons for the interval part if occurred;
3. Except for the FTP test from 03.01.2026 all workouts have been done using ERG mode;
4. For one workout I switched, and the Bryton S810 was a controllable device of the smart trainer. For most of the time the Elite Justo controlled the watts and workout in ERG mode;
5. Screens are from Compare the watts;
6. Sometimes the workout timeline is moved, that is due to the different methods of pausing the activity for each device, mostly the MyWhoosh (elite justo) recording is moved. I adjusted it in the Compare the watts by time offset, and the detailed comparison is correct. Due to that, the average watts for the entire workout are different and not correct. Then the interval part can be compared;
7. For Favero and Xcadey there are L/R balance data;
8. Sprints are much better recorded on Favero and Xcadey, and showed more reliable watts;
9. The maximum data from Compare the watts and recorded in the file is different for Favero and Xcadey;
10. I noticed different readings of watts during workout for all devices, for all of them I have 3s average watts so that should not be the case;
11. I identified some issues with displaying watts, I connect Xcadey and Favero to Garmin Fenix 8 and to MyWHoosh and it presented different readings;
12. I connected Xcadey as power source to mywhoosh and Elite Justo as controllable device for workouts in Mywhoosh, and the watts were displayed different on the Mywhoosh, and different on Garmin Fenix 8;
13. Favero and Xcadey are more sensible and reads all fluctuations of wattage more reliable;
The results overall:
1. Are consistent for all power sources, the graphs, watts and the cadence recorded are not identical but similar;
2. The comparison to other sets is always different, never been the same and within 1%, between the sources;
3. The graphs are very similar, Favero and Elite Justo are closer, and the GAP is probably around 1-5%;
4. The GAP for Xcadey is bigger, around 1-6%, except for two days 24-25.12, were I noticed some serious issues for all devices, the readings on all devices were strange,
5. The watts recorded and presented by Xcadey are always higher, around 5-10w from Elite Justo;
6. The maximum watts are much lower on Elite Justo and certainly not accurate;
7. Based on the workout assumptions, Elite Justo was in a lower or middle range of watts required, Favero Assioma was always below, Xcadey always met the requirements,
8. Favero and Xcadey L/R balance are very similar, the differences are very low;
9. I have different FTP based on the results obtained from all devices, between 352, 357 and 362w;
10. I charged Favero and Xcadey 16.12.2025 and today so 14.01.2026 the batter level is 10% (Xcadey). During that period, I rode more than 50h. However, the readings are not representative as my son (1.5 years) loves to spin the pedals, and the Xcadey was very often activated, even when Favero was not installed,
11. On the 12th of January I decided to swap pedals, and I installed Favero on my second bike. For me the results of Justo and Xcadey are reliable and enough. I just adjusted my FTP for the readings from Justo and Xcadey.
Riding for around 4.5 years with a power meter I still don’t know which is the most accurate one from those three, however I have one conclusion from my side. If you use power meter, perform all tests on it, that is crucial, and you should stick to it. If you change power meter, you always should perform a new FTP test on it. Even if it shows some lower or higher watts, you will have the proper and valid readings. I didn’t notice any unusual results so one showed 400w and another 600 w, except sprints, for sure that is the biggest flaws of a smart trainer due to their build and way of working. I also noticed that the feeling of 200w outside is a bit different than inside using all three devices. After all rides and tests, I would say that the watts are in the middle. I will repeat it when the weather will be more convenient in Poland. Lastly, my Favero Assioma now has some issues with the body, I changed the bearings but now I felt some play, again. It was noticed by many people in the past.
If you have any suggestions/comments/questions, I’m happy to answer.
