Kickr Core v1.4.8 not dropping to zero and power is too high

After upgrading to Kickr Core FW v1.4.8 and Zwift 1.60.0 (since Saturday 2024-03-09) there seems to be an offset on the power reported from Kickr Core. It is most noticeable when attempting to supertuck. The wattage does not drop fully to zero, like it used to do (at least not for several seconds), but seems to have a baseline offset of around 27W. My 20min avg from Kickr Core was 271W compared to 254W from Stages. I have done a lot of DRs and it has always been the other way around (Stages reporting higher than Kickr) and Kickr used to drop to zero as expected.

From yesterdays race: zwiftpower analysis set_id 412921 (my messed up numbers caused Zwift to bump me to B for at least 90 days).

Easy ride from Saturday with lots of coasting: zwiftpower analysis set_id 412608
One sample suggest that it takes 18 seconds to drop to zero.

Sample ride on v1.3.17: zwiftpower analysis set_id 411889

See more dual recordings at zwiftpower profile 3892276

I was planning to do some testing today, but of course there is no repro. I did power cycle the Kicker Core after the race yesterday, but I am 98% sure I also power cycled it after updating the FW to v.1.4.8 on Saturday.

Today (Analysis set 413210 over at ZwiftPower if you want to have a closer look) it drops nicely to zero and the Stages power meter reports higher numbers):


Zoomed in

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Have you performed a manual spindown with the wahoo app?

Yes, several times, but since v1.3.17 it will do auto spindown.

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Even though a manual spindown is still possible, there’s no way to disable the auto-spindown AFAIK so it will happen eventually

Hi, I’ve also had the same issue but with my Kickr V6, at first I thought I had good legs, but after a couple of rides I could see that my power meter wasn’t matching up, the higher the power the bigger the discrepancy and like you said it seemed to take longer than usual for the power to go down to zero. I’ve gave up and went back to a certified reconditioned V5 and it matches within 1% with my power meter. I’ve emailed Wahoo but just get the usual checks and tests to perform. I’m thinking it could be a software issue?

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It’s pretty clear the issue is with the Kickr V6


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Hi Stig,
It could be the belt has lost some tension over time.

Take the plastic cover off and nip the belt tensioner up around a full turn.

I am not sure how that would produce the issue in the initial post (power not dropping to zero), but the Kickr Core is brand new (since November 2023) and as already stated the problem has not reproed since Sunday (raced yesterday and did several supertucks ;))

I got the same issue you had. Goes to 24 watts and then drop down watts per watt very slowly. weirdly the cadence goes up to 120 without me pedalling.

do you still have the issue or any Tipps what I could do?

I only had this issue on two rides. Went away after I cut off power to the Kicker Core (full reboot). I have not seen it since. Not sure what happened.

I had this after riding up Epic KOM. I did a few reboots and got onto Wahoo who suggested I do a Factory Spin down. Its in a hidden menu on the Wahoo app because it can damage the trainer and should only be done if asked by Wahoo.

It happened after coasting from very high flywheel speeds, and I was able to replicate the issue in Wahoo app, Zwift, and IndieVelo. Neither did it matter if I use virtual shifting or manual shifting,

The issue mostly went away, but has occasionally reappeared after hard climbs. I’ve found that adding a little tension to the belt (usually on or two turns) stops the issue.

There are a few posts on this and I really think Wahoo need to address this. Especially if it is being caused by belt stretch.

I suggest reaching out to Wahoo support.

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For me it went away after a manual spindown + poweroff. Did not come again after that but I don’t trust it fully.
As you said next steps would have been factory spindown+belt and then wahoo support.
Thanks for sharing your experience, I hope wahoo is having a closer look at this.

I have the same issue with my Kickr Core and it began when i started using virtual shifting with zwiftclick

I can’t supertuck and a few races later i was bumped into B cat (not sure if related).

Interesting. I do not personally use virtual shifting very often though I do have Zwift Play controllers, with a Kickr v6

I used Zwift on a new machine / fresh app install the other day and it defaults to on and I started having this “won’t go to zero watts” problem (coupled with higher cadence though I wasn’t pedaling, from a technical perspective: comedy).

I tried the power off / power on thing and it was still happening.
I disabled virtual shifting, still happening (so, not sure virtual shifting is a cause, or just correlated…)

I just used the wahoo app “tap your trainer 10x” thing to open up ability to spin down and did that. Now at least from inside the wahoo app it does go to zero watts, hopefully that did the trick.

Not looking forward to cracking the unit open and playing with belt tension, hopefully that’s not needed

I tried isolating everything; Bluetooth/Wifi interference, operating system, device, belt, software (indieVelo, Zwift), chainline, gear combination, virtual shifting on/off, cyclist, trainer, using separate cadence sensor.

I never found the source, but suspect it is an issue with auto-calibration, vibration, and pedalling imbalances. It seemed to pop up if my Wife had used the bike and trainer and I think she has a larger pedalling imbalance compared to me.