Kickr Core erg mode brakes locking

Not sure if this is a Kickr Core issue, or a Zwift issue, but either way hopefully someone can help.

Every now and again, but more frequently recently, I get the issue where my Kickr Core applies excess resistance for no reason - to the point where it’s almost impossible to turn the pedals.

As an example of what will happen:

I start Zwift and connect my trainer on the connection screen and start the workout. I’ll then join an event.
While in the pen for the event, I’ll find my Kickr core is applying an insanely high level of resistance.
If I do a spindown/calibration, it releases all the resistance correctly and I can ride normally while I do the spindown. The spindown is fine.
The second I go back and rejoin the pen, my Kickr Core applies the extreme resistance again for no reason

Today, it took me 10 minutes of turning everything off/on again, several times, before I didn’t have the issue. However, during the group workout, I noticed that the resistance was still too high - I could really ‘feel’ 150w (zone 1) whereas normally it would be virtually imperceptible. Zone 5 was almost impossible to turn the pedals - I had to turn erg mode off (and the resistance still felt high).

I’ve had this happen 5 times, but after each time turning it off/on and doing a spindown resolved it, but today’s the first time it’s persisted during a workout.

Any ideas? My kickr core is 3 months old and has only done 100 hours.

Are you possibly experiencing the “spiral of death” in ERG mode? What is your cadence when this happens?

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I have also been having issue today with my Kickr Core the resistance is stupid, my device is brand new and been working fine until today. I am also having an issue with the game loading when it does eventually get in I have NO routes to choose from.

100% definitely not the spiral of death - the resistance kicks in even when I’m in the pen, after spindown, at 90rpm. My FTP is 296 and I’m finding it hard work pushing 150w, which I would be able to do even at low cadence.

Someone mentioned that this might be the optical sensor being dirty, but it comes and goes (this is I think the 4th or 5th time I’ve experienced this) so I’m not sure it can be that. Also, when I do the spindown the brake releases correctly, which is why I’m thinking it might be the software (Zwift) incorrectly sending instruction to the trainer about the resistance to use.

Put it this way, the trainer is applying resistance so high that when pedalling you can hear the sound of the wheel pulling through whatever it is that is clambing down on it - a bit like pedalling hard on your bike whilst squeezing your brakes hard.

Interesting. As it happens, I had loads of problems getting into Zwift today, lots of No Signal errors that I haven’t experienced for 2 - 3 months, including No Signal from my HRM strap which I’ve never had before, then the signal dropping out…it took me 10 minutes and multiple restarts to get in. No changes elsewhere in my set-up.

@B_Bridges I had this the other day. Very frustrating. Just as you say, the pedals had little resistance, then over ~5 seconds increased until I couldn’t turn the pedals.

Took me about 40 minutes to track it down.

In the Wahoo App, which I only use for calibration, the power was set to a high fixed value. I changed that number to a much lower number, and changed mode from fixed power to resistance or curve or something. Anything except fixed power. Instantly fixed the problem.

So yes, it was the spiral of death, but coming from an unexpected place that wasn’t Zwift.

(And for disclosure, I was using Peloton, not Zwift. Which’ll likely be both the first and last time)