Resistance on Kickr Core failing

The resistance on my Kickr Core always drops to nearly nothing, and sometimes ramps back up, on Zwift rides. It does not do this on Wahoo SYSTM training rides. It ruins my Zwift training plans, which are always done in ERG mode, because it will not hold the target watts. When the resistance fails, the watts/power displayed on the screen do NOT drop. That is, the display will say I’m still pedaling at X watts even though I’m practically free-wheeling.

A) I’ve worked with Wahoo support but to no avail. They say it is interference from other devices like a fan but the problem persists when ALL other device are off. (and SYSTM works fine with them on)
B) I’ve read all the “known bugs” posts but those doen’t help me. It is insufficient to just accept that it doesn’t work correctly and have to live with it.
C) This happens with ERG on or off.
D) I’m using a 3 year old iPad. I’ve not read anywhere that the iPad specifically correlates to such issues.

Has anyone found a real solution to the problem yet?

Hi @Robert_Barth

Welcome to the Forums!

That’s a tough one because if you’ve been in contact with Wahoo support and they’re telling you it’s wireless signal interference, that’s almost certainly the same conclusions Zwift support will draw.

That being said, if you contact Zwift support (which may require some patience while we work through the rudimentary troubleshooting), if it reaches a point where we’ve exhausted our resources to help you, we can gather your log files and data, and flag it up to a higher technical authority of the team to investigate any possible bugs or known issues.

That’s the most honest answer I can give you and what may very well likely happen for this type of issue.

Feel free to contact us here and opt to “Start chat”, go through the initial Solvvy portion of the process at which point you should then be able to send Zwift Support an email or chat with a live agent.

I had this problem with a Core. I eventually got Wahoo to replace it, and the problem is not there with the new one. I tested the environment with a spec A and there was no significant interference to explain the constant issues I was having - it started worse than my Snap and got worse over the year I had it.

I had wireless issues with that one trainer more than any other - I had a Snap before that, and the replacement Core and the Kickr V5 I have now all do not have the same issue.

I can only surmise a wireless problem with that one trainer, whether it was poor connection of the antenna or some other assembly flaw, a design issue they corrected - impossible to say without inside knowledge.

Video I made about my experience (happened to be during Zwift Academy last year)

It does seem like there are some conditions within Zwift that make it more likely to happen - but I haven’t looked into it in detail.

What you say makes a lot of sense, Craig @Craig_D_Mart

If one is exhaustive in exploring all other troubleshooting options, then I suppose that a hardware fault is the last thing to check off the list.

In these situations, we tend to steer KICKR using Zwifters to Wahoo Support as the best resource for help.

It still seemed like Zwift was far more sensitive than using my Garmin to control the trainer, @Steven_D - I never had a dropout using my edge for workouts, and if you look at the video, the dropouts there happened EXACTLY at the start of the sprint segment two days in a row.

I firmly believe there’s something on the Zwift side that’s making it worse, but it’s almost undoubtedly weaker RF performance from that particular trainer as well. (In my case, not judging Robert’s, as I didn’t go through all the steps I did in my own house at his, obviously)

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Steven D, well, now it is NOT confined to zwift. It happens while in Wahoo’s SYSTM workout too. Still, they claim no culpability or responsibility and say it is “interference”. Yet, they have now made a wired connection for their other trainers (does not work with Core). I’m new to cycling but not new to wireless telecom. The problem isn’t interference; the problem is their product’s inability to SHIELD from interference. I am VERY frustrated because I can’t train indoors with this. Maybe I should switch ti Tacx??

Craig, seems to me there is clearly a flaw in Wahoo’s equipment. Do I understand you correctly to say that you replaced your Kickr Core and the new one does NOT have this problem? Wahoo’s offer to me is to first send my unit to them and they will send a factory-reconditioned-unit ( aka USED) as a replacement with a few weeks. An unsatisfactory offer.

Steven D, I started with Wahoo Support; they are NOT supportive.

Steven D and any/all readers on this forum. Because Wahoo has not yet offered an acceptable solution, has anyone found a solid solution?
Such as; Windows PC works with core better than iPad
or, newer version iPad works
or, a specific mesh network works better
or, a wired solution (hack?) works better?

Robert - 2 things - Never had an issue using RGT or Garmin head unit to control trainer, and that only happened on 2 specific rides, the Zwift Academy assessment rides. On both of them, at EXACTLY the same spot in Watopia, the resistance went to zero.

Those things point at Zwift as a contributing factor. Most times when something goes wrong, there are multiple contributing “causes”. I know I always have to argue with people when they do failure analysis and come back quickly having found THE cause (and stopped looking). Based on what I saw, Zwift is definitely doing something at gradient reversals that can go wrong.

Bluetooth, Ant+, 2GHz wifi all use the same frequencies. You can move which channel you’re on to avoid your own wifi network jamming Ant+ & Bluetooth - but you can’t control your neighbours, and lots of devices are advertising their wifi network for wireless management all the time.

I’d suggest the following steps to try to improve your situation:

  1. Move to wired or 5GHz wifi for your device running Zwift and any other network devices in the same general vicinity. Everything in your house if you can.
  2. Switch between Ant+ and Bluetooth (use whatever you weren’t)

On Wahoo’s offer though - that’s exactly the offer I took. The reconditioned replacement works perfectly. I don’t understand why this is unsatisfactory for you. I got my replacement the next day. They won’t guarantee that time period, but they shipped the replacement as soon as they saw the item in Purolator’s hands.

Your comments are reassuring. Thanks. I’ll see what works for me.

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Hi Craig, you might be on to something with the Zwift software itself. I have a 2 year old Snap (V2) and find here is a particular training session on Zwift that simply drops resistance and at the same stage of the session each time. I regularly experience resistance drops or no change in resistance. I was riding this morning (not in ERG mode) and gradients had no effect but downhill would increase resistance? That is a -3% felt like a +3%? I run all connections through an iPhone XS Max then onto an Apple TV 4k. I figured the issues lay within the hardware setup but perhaps it is my Kickr Snap? I’m looking for a decent computer to run the system.