Assioma Uno and Wahoo Kickr Core - dual power and calibration

Hi Zwift community,

I have been riding on Zwift for a couple of years using my Kickr Core and managing to calibrate easily with the spanner/wrench tool before races. I would like to dual record power as I have the Assioma Uno pedals that I use out on the road IRL.

I would prefer to use my pedals as the main source for power reading in Zwift so I have the closest comparison between virtual and real-life training data.

However, having selected Assioma as the power source yesterday they are overreading considerably in Zwift, where I am able to calibrate them. I assume I need to calibrate the pedals for Zwift but there is no spanner/wrench icon and I can’t find anywhere in the forums where this issue has been described before.

Any help or advice would be most welcome.

Kind regards,


Hi @Oli_Brand, welcome to the forums!

Most of the time the advice will be “don’t use Zwift to calibrate your equipment, Zwift might not have the most up-to-date software/specs for the trainer/power meter”.

You should use the Wahoo app to do spindowns on the Kickr Core, and the Assioma app to calibrate the pedals. Zwift will use that calibration info, you don’t need to use Zwift to calibrate anything.

You should use the assioma app to calibrate the pedals.
Similar for the Kickr, use the whaoo app to make sure the firmware is up to date and do the spin down test there.
How much over are they reading? if they are single sided it might be that your left leg is more powerful than your right and so the reading will be higher (as it is the left leg doubled to give overall power).

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Also, make sure you have disabled the “double the power” option within the assioma app; Zwift already doubles the measurement from Unos when connected via bluetooth so it’s not needed.

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Hi Mike,

Thanks for the swift reply and warm welcome. I shall look to change my calibration approach to the app and not Zwift.

I calibrate my Assioma pedal often as I have to move them between two bikes and the crank arms are slightly different lengths. If I place my bike on my trainer, calibrate the pedal and connect it to my Elemnt Bolt, the power output ‘feels’ right with regards to effort and reading. However, if I then disconnect it and connect it to Zwift, the power is considerably higher. What would normally feel like Z1 recovery is reading much higher, around Z3.

Thanks again for your help and support, it is much appreciated.


Hi Chris,

Thanks for helping me out here. The reading is considerably over. When pedalling what would normally be around a Z1 moving into Z2 warm up, I am seeing number that represent Z3 into Z4.

I will ensure that I use the calibration on the Wahoo app from now on following your response.

Thank you,


Hi Colin,

Aha! Maybe this is the problem. Is this an option that is not normally considered when using the pedals with a head unit, such as the Wahoo Elemnt Bolt that I currently use? I ask because I have not disabled this and, antidotally, my power on the road seems in line with other riders (as much as it is possible to compare) and certainly not double!

Many thanks for your support.


are you able to record the wahoos power reading on your head unit while using zwift to see if it matches that?

One thing to mention, the “double the power” option will only affect Bluetooth connections - as far as I’m aware ANT+ connections work “properly” out of the box (and the option has no bearing). So if your Bolt is connecting to the pedals over ANT+ it should be reading correctly.

Are you using bluetooth to pair the pedals to Zwift out of interest - if you are it might be worth seeing if you can try via ANT+ (or as Chris mentions above, connect the pedals to Zwift and your Bolt and see if both readings differ).

Hi Chris,

I am not sure, I will have a look at how to do this and give it a try.

Thank you,


Hi Colin,

I see. Yes, I am using bluetooth to connect the pedals to Zwift. I will investigate ANT+ to work out how to do this.



Thanks for the update; in that case I would say the quickest solution would be to connect to the pedals via your phone’s assioma app, disable “double the power” and everything should then connect as normal in zwift (though the latest update has introduced some bluetooth connection issues to windows 10 devices) and report the correct values (which will save you looking into ANT+ connectivity).

If you connect your trainer to your garmin (connect to the power source not the trainer or it might try and control the resistance and do weird things when zwift also tries to control it)

then it will display the power from the trainer you can see if this matches the power zwift is showing from the pedals.

maybe you’re just a beast at indoor cycling :grinning:

I am facing the same issue, but with Assioma Duo pedals. I haven’t had a chance to dual-record a ride yet, but they seem to read >10% higher than my Kickr. I did a factory spin-down calibration on the Kickr last night and no change. It is an older bike that has never had drivetrain maintenance (like ever), but I wouldn’t think the drivetrain friction losses would be that much. I’ve calibrated the Assiomas, checked the crank length is correct, and have them set to send 1 value to Zwift (since Zwift can’t pair with two separate power sources at the same time).

Of note: I’m about 80% convinced at this point that the pedals are correctly reflecting power input at the pedal, given readings & perceived effort from outdoor riding. There’s also far less than can go wrong by measuring at the point of contact versus literally the final point before the rubber hits the road (rear hub). That said, I now have two important questions – assuming I’m not missing some configuration thing:

  1. If I’m using the pedals outdoors, should I also use them in Zwift?
  2. What are the ethics of using an objectively correct power meter for Zwift racing, when the reading significantly conflict with what my trainer is reporting? I absolutely do not want to cheat, but there are two things in favor of the pedals (1. they’re actually accurately measuring power output at the nearest point to my body, and 2. I suspect many, many other Zwift racers use power meters to record rather than their trainer, so now I wonder about what kind of disadvantage I may have had for the whole past year). I’m at a loss as to what to do.

All this said, I know the two of us can’t possibly be the only ones using Assioma pedals with Kickr trainers, and surely many, many more riders must not be seeing this discrepancy, so hopefully someone can help figure it out.

Clean your chain! Could easily be 10% loss of watts in the drivetrain if it really is poorly maintained. You probably need a new chain too, they don’t last forever.

This appears to have been the issue and now having disabled the “double the power” option I am getting very close readings from both the pedals and the Kickr. Thank you so much.

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