Kickr suddenly felt very heavy during cooldown section

Hi all!

I’m relatively new with Zwift and Smart trainers. Since two weeks I have been biking with a Wahoo Kickr Core (2018) and Zwift through a high end desktop PC, connected by an ANT+ dongle with a 1.5 meter USB extension cable from PC to near the base of the Kickr. In Zwift I have the Trainer Difficulty setting to about 75% and for Training setting I have ERG mode activated.

First of all, I’m having a blast with this gear!! :smiley:

However last Monday I was riding the #2 Zwift Academy Ride 2019: Race practice. This ride is 60 minutes. Now, it appeared that about 55 minutes in (75 - 100 Watt cooldown section) the
Kickr suddenly became very very heavy to pedal?! Like 18% incline heavy. There also appeared a short message in the center databar (which is always on top of the screen), but unfortunately I missed it. I was kind of scanning all my gear to figure out what was happening… I did momentarily stop pedalling before the issue occured and it is unclear to me if the increased heaviness was some kind of punishment or a bug haha.

Does anyone recognize this? Is this a bug or a feature?


Welcome to Zwift @Nando_Biker

Here are some info on how to do a workout in ERG mode.

On a fraction of my rides, using sim mode, I’ll get a single spike of increased power, where the resistance suddenly goes up 100 to 200 watts for about a second. Most rides this does not happen, and I don’t recall it happening more than once in a ride. The effect is transient; everything is normal, there’s a very short spike, and then everything settles back where it should be given the incline, gearing, cadence etc.

Equipment: Zwift on Windows 10 PC, KICKR 2014, ANT+ directly under the trainer, using a USB cable attached to a powered USB hub.