KICKR Core gets stuck at ~40-50 W after stopping in ERG - disabling Zwift Click / virtual shifting fixes it

KICKR Core gets stuck at ~40-50 W after stopping in ERG - disabling Zwift Click / virtual shifting fixes it

I’m starting a new topic because some of the existing KICKR/virtual shifting threads are now very long and seem to contain several slightly different resistance problems. I wanted to describe the specific issue I’m seeing, and the workaround that appears to fix it consistently for me.

The problem

During a Zwift workout in ERG mode, everything initially works normally.

The problem occurs after I stop pedalling long enough for Zwift to enter ERG bailout mode.

When I start pedalling again, Zwift tells me to “Hold steady to re-activate ERG”, but the resistance can remain extremely low.

I can be pedalling at around 75-80 rpm and only producing roughly 40-50 W.

Increasing cadence does not restore normal resistance. Sometimes shifting through a lot of virtual gears changes the resistance briefly, but it falls back again.

The KICKR itself remains connected to Zwift as Power, Cadence and Controllable Trainer throughout this.

What I found

I reviewed the Zwift logs and FIT files from two rides where this happened.

On the most recent ride, I was able to reproduce the behaviour twice.

The useful sequence was:

  • ERG working normally at about 130–135 W.
  • I stopped pedalling.
  • Zwift reported: “ERG mode disabled temporarily”.
  • I resumed pedalling at normal cadence.
  • Resistance remained stuck at roughly 40-50 W instead of returning to the ERG target.
  • I went back to the pairing screen and disconnected/deselected the Zwift Click controllers.
  • Zwift then logged: “Disabled virtual shifting on KICKR CORE”.
  • The KICKR itself stayed connected as Power, Cadence and Controllable Trainer.
  • Shortly afterwards Zwift reported “Re-activating ERG”.
  • Resistance immediately returned to the correct workout target.

I then re-enabled the Zwift Click / virtual shifting and continued riding.

After the next time I stopped pedalling, exactly the same low-resistance problem occurred again.

I disconnected the Click / disabled virtual shifting again, and ERG recovered again.

After that I left virtual shifting disabled for the rest of the workout.

So for me the repeatable pattern appears to be:

Virtual shifting enabled → stop pedalling → ERG bailout → resistance stuck around 40-50 W

and:

Disconnect Zwift Click / disable virtual shifting → ERG reactivates normally

The trainer itself does not appear to be disconnecting when the problem occurs.

Workaround

The workaround I have found is:

Disconnect/deselect the Zwift Click controllers so virtual shifting is disabled.

Once virtual shifting is disabled, ERG recovers and the KICKR behaves normally again.

Similar reports

There are already a number of related reports on the Zwift forums. I’m not suggesting all of these reports are necessarily the same bug, which is partly why I created a separate topic.

My specific issue is that after ERG bailout, resistance becomes stuck extremely low, and disabling Zwift Click / virtual shifting allows ERG to recover normally.

What do you see if you run a log file through trainerdx.com? All good there?

I find it interesting since virtual shifting isn’t used when in ERG mode, though the controls are still active so another test would be to only turn off virtual shifting in settings while leaving the controls paired.