I recently bought a Zwift Ride with the Kickr Core. During my first few rides, I noticed the power readings seemed a bit too high. To double-check, I paired my Assioma DUO pedals and did a comparison.
Turns out, the Kickr Core is reporting power about 6% higher than the Assiomas. Cadence is also consistently 2–3 rpm higher on the Kickr.
Everything is updated to the latest firmware. I did a spindown calibration on the Kickr Core after a warm-up ride, and the crank length on the Assiomas is correctly set to 170mm.
Is anyone else seeing similar discrepancies in power and cadence with the Kickr Core?
This is Haziel from Zwift Support. Thank you so much for sharing your detailed observations and taking the time to compare your Kickr Core with the Assioma DUO pedals. I completely understand how important it is for you to have accurate and consistent data, especially as you work on fine-tuning your training and performance metrics.
Since you’ve already updated your firmware, calibrated your Kickr Core after a warm-up ride, and double-checked that your Assioma DUO crank length is set correctly, could you please let me know if you’re seeing this issue on both the Wahoo app and Zwift? This information will help us aisle down the problem
Additionally, have you noticed if the difference in readings remains stable, or is it fluctuating?
Please remember that you can always reach out to us at Support@zwift.com. We will be happy to support you further.
Hi @Mike_Rowe1, I saw the video a while ago, he didn’t seem to find any issues indeed.
I’m starting to wonder if I might have a faulty unit.
Not sure if the cadence is different from the one on the Assiomas, if this is a fix I can perform myself.
Today, I’ll be measuring cadence using a separate Garmin sensor on the crank, just as an additional reference to verify the accuracy of the Assioma DUOs. I’m confident they’re correct, but it’s always good to double-check.
The cadence isn’t fluctuating, it’s just consistently reading 2–3 RPM higher than what the Kickr Core shows.
Here is a screenshot from a zoomed section from the cadance taken from the Zwiftpower site.
The Kickr Core doesn’t have a cadence sensor, it does not measure crank arm revolutions. It estimates cadence based on what’s observed at the rear axle, and I’d say it’s doing a pretty good job. The Assiomas are measuring crank arm revolutions. If the power difference bothers you I suggest talking to Wahoo, but with only two power meters it is hard to guess which one is more correct. Also check that crank arm length is consistent both in the the Assioma settings, and on the cycling computer you are using to dual record.
I compared the Assioma DUO to a Tacx Neo 2T some time ago, and the difference was less than 1%.
The crank length settings are correctly set to 170 mm in both the Assioma app and my Garmin Edge, so there’s no issue there.
If cadence and power readings are off, there may be a problem with the unit. Over the course of an hour, a difference of 2–3 RPM is significant in my opinion. If the cadence is being misread, it could also be affecting the power output, higher reported cadence could result in an overestimation of power.
Your Kickr Core is estimating your cadence from fluctuations in the power while you’re pedalling. That has nothing to do with the way that it measures the power.
Is this something you’ve heard directly from the manufacturer?
It still seems odd that power and cadense are overreporting. That would suggest the Kickr Core thinks I’m pedaling faster than I actually am. If what you’re saying is correct, then it would mean I’m pedaling in a way that causes the Kickr Core to interpret a higher cadence, leading to a distorted power distribution.
Now that I think about it, could a left/right leg imbalance be a factor? I know I have a known imbalance 53% left / 47% right which is confirmed by both my Neo T2 and Assiomas..
No, I haven’t heard this directly from Wahoo, but I can assure you that this is how it works.
I can also assure you that any inaccuracies in cadence aren’t related to any power inaccuracies. The trainer measures/calculates your power, and then it looks at variations in that power to estimate your cadence.
I have been seeing the same results (or better call them issues) since I have got the Assiomas Duo.
I have Kickr Core and it regularly overreports the power by 3-6 percent, depending on the length of the ride and the type.
I have done all the calibration numerous times, and this drives me crazy, to be honest. The famous two clocks and a man dilemma.
Sometimes it is something manageable like 2%, but it’s always the Core reading too high.
Today, I did a 1:45-hour ride, and the final score was 141w to 134w in favor of Kickr Core.
I’m running the latest firmware, and the topic you linked is marked as solved. I’m not experiencing the exact same issue, when I stop pedaling, my cadence drops immediately to 0 RPM.
However, based on what I’ve read, it seems the issue might not be fully resolved…
I’m also using virtual shifting in Zwift, which was one of the main reasons I chose this setup.
I believe that there have been more than a few people who reported that the Kickr Core reads high. I know this from a friend as well, he has a KickrV5 at his house and a Kickr Core at his vacation home. His Core reads 10W higher than his V5. He also uses Assioma pedals, although Uno, not Duo.
