KICKR + CLIMB random tilt spikes

Hi,

I have recently started encountering very peculiar behaviour of Wahoo KICKR18 with Wahoo CLIMB. Basically on a completely flat route (imagine 0deg on parts of Fuego Flats) the CLIMB moves randomly in recurrent spikes of about +/-1 deg. It doesn’t happen all the time, just on 0deg flats and even there it seems random, but occurs in about half a minute to minute bursts of these up/down changes round about every second each.

I have done some experimenting and here’s the summary of the prerequisites:

  • KICKR+CLIMB connected via ANT+ to MacBook Pro (Late 2013)
  • ANT+ dongle on extension USB cable 1ft from KICKR
  • Bluetooth disabled on Macbook
  • All bluetooth devices in vicinity also disabled.
  • HEADWIND switched OFF
  • WiFi on 5GHz network
  • No other WiFi signals detected, channel 11 clear
  • No other apps and/or computers connected to KICKR+CLIMB apart from the MacBook Pro running Zwift

I think I can say with some certainty that there’s nothing that should be interfering with the correct operation. There’s single computer, single application, connected to KICKR+CLIMB via ANT+, no other ANT+ or Bluetooth devices present, no fans running, no signal interference.

Yet, it’s still there. The random up/down motion, every second or so, in random bursts, on the Zwift route (Fuego Flats) that’s completely flat and showing 0deg gradient.

The only explanation I think I can narrow it down is software. Either Zwift is sending these random tilt commands, or KICKR is misinterpreting what’s being sent via ANT+.

So I have done some digging into Zwift log file and I have found a very peculiar sequence of SIM GRADE commands that are not zero, where they should be:

[20:21:59] FE-C SIM GRADE -0.001
[20:21:59] ANT : FET grade set successfully
[20:22:00] FE-C SIM GRADE -0.001
[20:22:00] ANT : FET grade set successfully
[20:22:01] FE-C SIM GRADE -0.001
[20:22:01] ANT : FET grade set successfully
[20:22:02] FE-C SIM GRADE -0.001
[20:22:02] ANT : FET grade set successfully
[20:22:03] FE-C SIM GRADE -0.000
[20:22:03] ANT : FET grade set successfully
[20:22:04] FE-C SIM GRADE -0.000
[20:22:04] ANT : FET grade set successfully
[20:22:05] FE-C SIM GRADE 0.000
[20:22:05] ANT : FET grade set successfully
[20:22:06] FE-C SIM GRADE 0.001
[20:22:06] ANT : FET grade set successfully
[20:22:07] FE-C SIM GRADE 0.001
[20:22:07] ANT : FET grade set successfully
[20:22:08] FE-C SIM GRADE 0.001
[20:22:08] ANT : FET grade set successfully
[20:22:09] FE-C SIM GRADE 0.001
And so on…

Now I can see two possible scenarios:

  1. Zwift is sending wrong GRADE commands. Where it should be 0.000, it’s only very slightly around this number, or just the +/- fluctuation.

  2. CLIMB (or KICKR) over-interprets the GRADE commands, and for every value that’s just positive above zero, however small, generates +1deg tilt and for every value that’s just negative below zero, generates -1deg tilt.

Either way, the result of these minuscule random undulations (whether sent in error or deliberately) is a constant 1deg up/down oscillation of the CLIMB.

I’m not sure what changed in KICKR firmware or Zwift recently that could be causing this, but it’s becoming quite noticeable and very annoying.

Any ideas or insights anyone? I’ve contacted both Wahoo and Zwift support, but so far no joy.

I’m experiencing exactly the same kind of issues since the start of the L’Etape rides, but mine are the inverse - I get nothing for 5 or 10 minutes, and then a HUGE 5%+ or more jump in ascent or decent on the KickR climb.

I created a thread, to which I also got no response from Zwift on, despite them directing me here to request assistance.

/t/wahoo-kickr-climb-lag-or-delays-in-grade-variations/498788/2

I am getting the same thing and think it started after the France maps came on.

I just rode Ventoux and there were sections when it’s a steady grade but the Kickr Climb just randomly starts going up and down with a very jerky movement. It was so annoying that I turn it off. I’ve experienced this in other parts of Zwift recently.

I have sent a ticket into Wahoo. Will report back.

1 Like

Thanks Ben, it doesn’t seem just as an odd isolated issue anymore.

I’ve also noticed it happening more often and with larger oscillations since the latest update with France/Paris for everyone.

Wanted to circle back on this.

After more testing I figured out that my Climb was just broken. Specifically it would not go through zero smoothly and would get erroneous readings that jump around. This was very evident when controlling the Climb using the wired remote. What I think was happening in Zwift was that it was trying to change gradient but couldn’t get there and would then try again, resulting in weird movement that I reported earlier.

Wahoo have been great from a support perspective. They sent me a label to return the Climb and are now shipping me a new one.

It’s disappointing that it broke. I’ve done about 5000 miles on the Climb with lots of climbing. I wonder how long the new one will last.

HoweverX I rode tonight without it and really missed it. As did my bum. It really does make Zwift a more enjoyable (and comfortable) experience.