Wahoo Kickr Core Power Drop Since Feb Update

Since the Feb Zwift update I’ve been experiencing random sensor dropouts on my kickr core, the most recent being yesterday right before the end of a race. I seem to lose everything and have to unplug my trainer and re-connect to get zwift to pick it back up. I’m also using a Wahoo Tickr heart rate monitor and this drops too! - All connected via bluetooth using IOS companion to a MacBook Pro.

I have a team mate thats running the same setup but using Ant+ and she is experiencing the same!

Anyone else experiencing this and found a fix or fed back to zwift and had a reply?

I am the team mate with similar problems. Wahoo Kickr Core paired via Ant+ to MacBook Pro. No problems for 2 years and starting 7 February (update day) lots of race ruining power drops. All troubleshooting gone through.

Looking at the screenshot I think you need to select the Wahoo FEC option for ‘power source’ and ‘Controllable’ rather than ‘Kickr Core C389 64’ (this is an old protocol). It may have been set to this before the update and has switched after.

Good spot John,

But the user is using companion app to bridge so no FE-c option.

I would suggest getting an ANT+ dongle and pair it as FE-c

I have noticed 9 seconds power drop. Wahoo Core connected as Power source and Controllable, Inpeak Powercrank connected as Cadence source. Zwift latest version on iPad. Wahoo latest firmware *.12
Issue occured only once.

Yes sorry the connection is through bluetooth. I have the Kickr Core connected to a windows 10 laptop with and Ant+ dongle and I haven’t experienced any dropouts at all. Ant+ connected through FEC is a stable connection and always the best option if it is compatible with the users equipment.

Hi John, thanks for your input here, which Ant+ dongle do you use?

I have a old Garmin one that came with a running watch from years back. It is the full stick version rather than the modern sleeker one. I have heard that none familiar brands work just as well though although cannot verify that is the case. The following might be helpful :https://zwiftinsider.com/ant-dongles-for-zwift/

Hi @Danno_Race3R and @Crazy-Cat welcome to Zwift forums.

It’s unusual to hear that iOS and MacOS versions both have the same symptom. Have both of you tried uploading your log files to Zwiftalizer.com to spot issues? Here’s where to find your log files.

In Cat’s case - there was a session on Feb 23 where sensors connected, and a 2.5 hour ride on Tempus Fugit was completed. In Danno’s case - your last successful connection was also Feb 23 with a logout of 9:10 am UTC. Were both of you experiencing power drops on these rides?

Would both of you upload the log files from these specific rides to zwiftalier and see if there’s anomalies?


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So i dropped my ride log into Zwifalizer and this is what I got out.

Thanks for uploading that. That BLE chart don’t reveal anything out of the ordinary.

If you look at that ride in Zwift Companion’s Activities - there should be a timeline view where you can see the chart for power, cadence, and HR data. Do you see any sharp valleys where there’s zero data coming from the sensor? If you know for sure it’s not just times when you stopped pedalling completely, I’m curious to know which sensors dropped signal? All of them, or just power?

The chart you see on ZC corresponds to data in your FIT file for that session. Depending on what you see, I might ask you to email us that FIT file as the next step.

Thanks for coming back to me, so you can see on the graph (attached) that I lose everything right at the end of the ride, I can confirm it was a full drop of all sensors.

I also took a video of the race https://youtu.be/8GLMTGhWfjU if you skip to 57:50 this is right before it happens. The hr sensor goes first then everything else follows.


Thanks for sending along both of those. I’d like to ask you to send the FIT file for this Feb 23 event, please. Here’s how to locate the FIT file.
Email that as an attachment to support@zwift.com. In the body of your email, please reference this forum thread URL, and ask for Shuji.

You haven’t affirmatively told us yet, but when’s the last time you updated the firmware on your Kickr Core and Tickr HR monitor? Let’s eliminate this as a possibility, shall we?

There was a September 2019 firmware patch that specifically improved Bluetooth performance.

Here’s instructions for updating the Tickr

I’ve been having problems too; lot’s of dropouts and haven’t been able to solve the problem. I also seem to be showing lower power readings than expected for the gear and cadence.
I contacted Wahoo and they got me to do a factory reset and when I rode today the “feel” was ok, i.e. when I rode steady it felt steady but the power readings were lower than usual for the same effort/gear/cadence.

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Hi Shuji,

Emailing that over to you now to review, all firmware is up to date on the kit i’m running, I do a monthly check on this to make sure I’m on the latest software.

This morning I switched to Ant+instead of bluetooth for the first time, have to say the readings in zwiftalizer show everything was running really smooth so this may be the way forward from now on!

Good morning @Danno_Race3R, I see your email from four days ago, but I can’t find one from last night with a FIT file attached. Did you send from a different email? If so - please private messsage me what that is? Thanks.

Never mind @Danno_Race3R! I found it. One of my colleagues flagged it up to me just now.

Hi Shuji,

Apologies I think in my tired state I attached the wrong file for you.

Attached is the Fit file now for you.



(Attachment 2020-02-23-07-48-26.fit is missing)

(Attachment 2020-02-23-07-43-29.fit is missing)

Please email those - those files will not upload to the forum for security reasons.