Wattage underestimated

When riding outside, I can average a 200+ watts for more than 60 minutes (using Rival AXS Power Meter) and when riding inside with the Kickr v5 I can’t hold 200 watts for more than 2 minutes.

It’s not the same bike, but it shouldn’t matter, right?

I’m 6’1, 90kg and averaging 32 km/h outside. I have the feeling that the kickr underestimates (by 2) the wattage.

I tried the Wahoo Fitness app and Zwift, played with ERG mode and the results are always the same…

When you say “by 2” do you mean 2%, or by 1/2?
If the former, that is well within the accuracy range of a power meter.

Averaging 200W on an outside ride likely to have hills/rolling hills etc is completely different from averaging a steady 200W on an indoor bike. Just think hoe “average” can be made up… it could have sections of 1000W and sections of 1W

Also, might be worth checking your crank length/power meter settings on both bikes.

From what you report sounds like something is going wrong either with the calibration of the trainer or the power control. I’d contact Wahoo support, in my experience the support is excellent.
Submit a request – Wahoo Fitness Support


I meant 1/2. I wouldn’t mind a 2% difference!

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Hey @Dominic_Hamelin-Blai, and welcome to the forums. R u sure you have the latest firmware for the Kickr v5?

Have you submitted a support ticket?
CS staff may read posts in the forum and others may help you troubleshoot but in the meantime, if you haven’t already, def submit a support request.

Yes I do have the latest firmware (v4.3.) and yep, I have submitted a ticket! Wait for a response now.


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Sure. Be sure to come back and let us know what CS says. I wonder if something else has grabbed trainer control?

I remember when I got my first smart trainer in 2017 and I’d get wildly different readings from the trainer (a Cyclops Magnus at the time) where the trainer connected to software would report 200 watts but my power meter was reporting like 280 or something. Turned out to be a faulty trainer.

Is there any way you can get the Rival PM on the trainer bike? I used to check the accuracy and reliability of my Kickr Snap, then the Kickr ‘18 that replaced it by measuring its power output compared to 2 separate power meters. I realize not everyone has that luxury but even if you could borrow from a friend?

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