Wahoo Kickr Core Resistance dropouts

Hi there,
I have a second hand Wahoo Kickr core which i bought off eBay 2nd hand almost a year ago, and until very recently it has worked very well. However nearly every ride that i now do on it, there have been issues with power / resistance.
(I mainly use zwift, my house-mate uses the wahoo app and has similar issues)

When starting the ride, everything is normal however 5-10 seconds later, the resistance suddenly drops and so does the power reading.

  1. Power reads as expected for a few seconds
  2. Resistance drops and power slowly drops (i still feel like i am pedalling at the same power, since i increased my cadence)
  3. Power completely flatlines to ~40w, even when im not pedalling
  4. I try to push again, power reads as expected for ~10-20s
  5. Resistance drops and power flatlines to inaccurate values
  6. I stop peddaling for 30s then pedal slowly. Power seems normal again
  7. Same as 4
  8. Same as 5 except the power is not shown as constant
  9. Same as 6
  10. Same as 4 & 7 but pushing harder
  11. Same as 5 but at a higher power
  12. Same as 6 & 9
  13. Power reads as normal for a long time
  14. I change (virtual) gear in zwift and resistance drops
  15. Steady hard pedalling which just results in 2 spikes
  16. Huge spike of 1330w when i was off the bike and saving the ride

So it seems that the power readings come back to normal after a time of purposeful slow riding.
In terms of what i have tried to fix this:

  1. Spindowns - very often spindowns fail or said they have failed when i haven’t even done one. When i do manage to do one (usually after force quitting the app several time), 1 of 2 things happen. 1 - spindown works as it should, i load up zwift and the same thing happens as before. 2 - after 3-5 seconds, the resistance drops and the core thinks it’s speed is dropping.
  2. Followed multiple toubleshooting articles on wahoo, including https://support.wahoofitness.com/hc/en-us/articles/4407156565266-Spindown-Calibration-Troubleshooting-for-KICKR https://support.wahoofitness.com/hc/en-us/articles/4407140895378-KICKR-power-spikes-or-dropouts
  3. Done all sorts of combinations of turning things off and on again

One more thing is this doesn’t seem to happen in ERG mode in zwift. This is confusing as the problem lies evidently in the trainer not zwift

If anyone has any idea on how to fix that I’d greatly appreciate it. It could be to do with the cold weather in England currently but I would have thought that wahoo would have thought of this. Thanks :slight_smile:

I’d suggest testing out on different apps, but primarily the Wahoo App to see if you can replicate the issues outside of Zwift. Try the different modes and see what happens.

Also, while you’re the second owner of the unit, it still might be worth contact support directly.

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Thanks Glen. Yes the issue occurs in the wahoo app too - here’s a video of an attempted spin down (with mic) where essentially the same thing happens as in zwift: https://vimeo.com/1046303929?share=copy
I have contacted support but just wondering if anyone has any hints before they can get back to me :slight_smile:

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That video link is broken and returns a dead page, amusingly called VimeUhOh

The only thing I can think of (besides an internal hardware issue) is that you’re somehow getting interference.

This might seem too simple or you may have already tried it, but have you toggled Bluetooth Off then back On on whatever device it is you are using to run Zwift?

You mention you’re using virtual gears so I’m assuming the Zwift Play or Click. Are you also using the Zwift Cog? If not, are you able to get a smoother ride (i.e. more predictable resistance) using the mechanical gears on your bike?

What is it that you’re using to ride Zwift? PC, Mac, AppleTV, mobile?
What other sensors are you connecting and are you using the Zwift Companion App?
When you are riding are you 100% certain that all other apps that may be trying to connect to your Kickr, or are not overly willing to let the connection go, have been forced closed?

Thanks Glen - sorry about the video, i believe the link should work now. I use Windows PC, and i don’t own a specific single speed cassette cog but just use the 8/9 speed cog in combination with zwift gears in order to get optimum cadence in some longer rides. Both still “result” in (probably don’t cause) these power dropouts. I will try the methods you have suggested about bluetooth & apps :+1:

So a PC but what version of Windows?
What are you using for virtual gears?
Are you on the latest firmware for the Kickr Core and for Zwift and for whatever you’re using for virtual gears (Play or Click)?

I’ve had Spindown failures on occasion too and they are generally resolved by toggling Bluetooth off and back on, and/or uninstalling the WA, restarting my phone, then reinstalling the WA.

I’m sure you read in one of the troubleshooting articles that you should be riding the trainer for a good 10 minutes BEFORE doing the spindown in order to warm it up. This would be especially important if you’re trainer is in a place where its very cold.