Wahoo KICKR BIKE "Pulsating" Resistance Issue

Hey everyone,

Quick question to those who has the Wahoo KICKR BIKE.

I’ve had mine now for about 2 weeks, lovely bike, super silent and love riding it. But I’ve realised some weird “issues” with it that I just wanted to see if anyone else have.

So I do all my rides in ERG, and sometimes it feels like there is a pulsating feeling to the resistance.

Have anyone else experienced the same?

I got asked by Wahoo to do a test with set powers on the ERG. And what I could see is that the speed varies a little bit, and matches the “pulses” that I could feel in the bike and the pedals.

The feeling is a bit similar to ABS systems in cars, that instead of a constant resistance, there is a fast pulsating resistance. Oddly enough I feel it less the higher the cadence is. But at 200w at 80RPM it’s pretty noticeable (and annoying.

Here is FIT file uploaded into DC Rainmakers software, where you can see the speed being wobbly even if cadence is steady, with ERG power. The speed wobbles is similar to what I feel on the bike. For example in the middle of 300w, it was smooth for a bit, then it came back (as seen in the speed).

That looks like it has power smoothing on. I’d definitely disable smoothing and run the test again before even trying to look at the data.

I’ve had an issue before where erg alternates between vastly over and under-shooting the power target. Usually resolved by restarting one or more devices so I never got too far down the road of troubleshooting. However, I’m sure I read somewhere that this behaviour is almost always due to two competing devices trying to give instructions to the Kickr (mine’s just the trainer, not the bike, but I’m sure they’re similar enough.). This could be what’s going on for you, but it sounds like you’re talking about pulsating many cycles per second - my experience of the issue is more like one cycle every second (or even slower).

It has, but there was no instructions from Wahoo themselves when they gave me instructions to run this workout and send to them. I sent over the .FIT file so we shall see what they say…

Yeah, I’ve had that before on my Kickr that I had before, but there are no conflicts here. Only TrainerRoad on the phone working…

Hmm, we shall see what Wahoo says.

Competing devices and dropouts are like you say, longer in duration. This here is a weird pulse and power never drops.

Hmm - didn’t Tacx make a big song and dance about doing effectively the same thing deliberately when you ride over cobbles in Zwift and calling it ‘road feel’? Maybe you got a free upgrade! :shushing_face: :wink:

Better sign up for some gravel events. :joy:

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Haha, thats probably gonna be Wahoos reply, its a “feature”…

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Alright, so might have solved it: By turning of the Power Smoothing in the Wahoo app the pedal feel felt exponentially smoother, as I would expect them to feel.

Super weird that it had that effect…

Anyone else running the Kickr Bike and can try both settings and see if they get the same result?

I got my Kickr Bike about a month ago and have done 15-20 erg rides and can’t say I’ve ever felt what you’re describing. My normal cadence is low 100s and I rarely drop below 90 so I can’t say if it’s a cadence issue. I have smoothing on and rode with my Assiomas for the first couple weeks to compare and didn’t notice any huge spikes or drops. Kickr bike ran around 2-3W higher over all power ranges so just about spot on with what I should expect. The Assioma file was always more spiky as expected, but I don’t recall ever seeing huge jumps that would indicate the pulsating resistance changes you are experiencing. I’d reach out to Wahoo. It would be nice if you had a pedal power meter to compare.

Oh shit, yeah I am not that much of a spinner. Usually around 80RPM for Z2, and 90-95RPM for harder intervals.

The issue has actually nothing to do with the recorded watts (I think), but there seems to be a difference in how the trainer adjusts to whatever signals TrainerRoad or how it now works, is sending it.

Considering that turning off Power Smoothing made the pedal feel 100x better, something weird is going on.

Again, issue was pedal feel that felt sometimes like the Kickr Bike was using an ABS system to apply resistance, instead of a smooth resistance.

Already in talks with them, but feels weird that Power Smoothing off solved it… :open_mouth:

Usually pulsating is the magnetic resistance barely turning on at low resistance levels.

This is during erg mode correct? I wonder if it has anything to do with what “virtual gear” you are in. So on a normal smart trainer, if you’re in an easy gear, the trainer would need to apply more resistance than if you’re in a harder gear. Try shifting up and down and see if that changes the problem.

I’ve had multiple trainers and can definitely feel it when the trainer is adjusting. Like if I have 200W set, I can feel the subtle resistance changes the trainer is making to get my power to 200W. I’m not sure if that’s what you’re feeling but comparing to my Assiomas the max would be 20-30W for maybe a sec, and usually it’s a lot closer. I did have an Elite Direto and at the end of its life I would get swings if 100W above or below as the trainer tried to keep me on the erg target. But it would only happen if I was in the big front ring. Small front ring everything was fine. Which to me indicated that at lower resistances (the force needed by the trainer to get me the correct wattage, not actual power target) I was getting the problem. In the small ring with higher resistance I was fine.

Another thing to think about is pedal smoothness. The trainer is taking your force in the pedals multiple times a second to make adjustments. So smoother pedaling and more consistent power/force through the pedals will make it easier for the trainer and change less.

The last thing I will say is that it’s weird that power smoothing has anything to do with this as I thought Wahoo’s power smoothing was just a software thing to make the power look pretty and not actually doing anything to the resistance. But I guess not.

Correct, all in ERG!

This was on my mind as well, since on my other Wahoo Kickr, the faster the flywheel, the “smoother” in a sense, since you get the momentum. But with the Kickr Bike you have the magnetic resistance, and it seems to be locked 1:1 ratio and the gears I believe are just software gears.

Tried different gears and no difference.

Yeah my feeling as well… BUT since the smoothing is happening on Wahoo’s side of things, and being sent to TrainerRoad as smooth, it might actually be something going on there.

Because of course when I turn it off, it becomes “jagged” and shows the true data being sent, nothing smoothed.

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Yeah, smart bikes have a single drive ratio. It’s not 1:1 and probably closer to something like 3:1 or higher if I had to guess. Easy enough to find out when you count the flywheel revolutions you get from a single crank rotation, for anyone curious to learn the actual ratio.

As such, the “shifting” is not changing anything physically like we get with a real geared bike drivetrain. The smart bike shifting is only altering the baseline resistance applied in something like a Simulation or Resistance Mode. It will do nothing in the case of ERG mode use, as you experienced. We discussed this related to the Stages SB20 in another thread, and Stages confirmed this info. I am pretty certain the Kickr Bike is working similarly.

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I had a similar issue with my V1 Kickr bike that i got about 4 weeks ago. I initially opened a ticket with Wahoo about it. It was like the road feel the Neo has in Zwift but was only in certain instances, like low cadence, higher watts or resistance changes. You’d even get it in the first 3-5 pedal strokes when starting up. I found I was having to ride at a higher cadence than normal to avoid it or at least mitigate it.

Wahoo came back saying it was normal behaviour but I wasn’t really buying it. The issue seemed to have reduced a bit, so I thought maybe the belt or something was overtight and with use was bedding in and resolving the problem. But it was still there, and to be honest I was considering dusting off the trusty Neo again as it was affecting my enjoyment of riding it.

I was still in touch with Wahoo as I was also having a problem with my fit and the climb function, basically i have to keep it locked at around 1.5% for my fit to feel level. I again mentioned the rough feeling in the pedals, but this time described it as like the flywheel was unbalanced at times but would be fine it cadence increased. They came back straight away saying they have a resolution that will fix that issue. Gave me instructions on how to install a beta firmware. Based on one ERG mode workout today the issue is gone, it was smooth like butter. Once I’m happy after a couple of test spins, I then have to roll it back to a production firmware. So, I’m guessing the beta resets or recalibrates how the motor delivers resistance.

I have always had power smoothing turned off and was having the issue in both ERG and Zwift free riding.


Damn, that exactly what I’ve got, but you managed to describe it a bit better! :slight_smile:

Awesome, thanks for this, I will mention this to their support once they get back to me.

Do you by any chance have he firmware number or some sort that I can use to mention to them?

Thanks again!

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Update again, unfortunately!

So on the bike now, vibrations/pulsing is back…

Rode for awhile and then was like, maybe I should shift up, even if I am riding in ERG… BAM!

Pulsation gone. So even if I am riding in ERG, the difference in resistance feel went from pulsating and feeling wrong, to butter smooth, by shifter to the big ring in the front.

Obviously seems like a software issue then…

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They had me install .27 I haven’t been able to get on the bike since but hopeful the issue is resolved.

There seems to be a few different versions, so guessing they recommend which ever one suits your issue, if they think it’s a firmware fix.

It was weird as I had explained the issue a couple of times and they asked for videos etc. When i mentioned it was like an imbalance in the flywheel they suggested the firmware option.

Hopefully yours can be resolved as well. Have a zwift race tomorrow so should get a good shake down of it in that.

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For those who might have the same issue, there is a fix being administered now (see below).

I have not included the passwords for the firmwares for obvious reasons

I will report back if it improves the feeling on the bike.

This is the same thing you did right, @dazbert? Did you feel any difference?

Yes that’s the same thing. I still haven’t been able to get on the bike this week to verify my first ride. The first ride though went perfectly with no virbation/pulsing etc

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I’ve done 2 rides so far, huge improvement on my end :slight_smile:

Going to keep testing for a week or so, and then get back to Wahoo!

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I just started having the same issue with my Kickr Bike. Had power smoothing on so the display wattage was the same, but I could feel huge differences in the resistance. I turned off power smoothing but it did nothing. I was still getting huge swings, but now I could actually see them. I was doing a SS workout with a 295W target, and was getting constant swings down to 240ish up to 340ish, with the worst being around 200W and up to 405W. It was super frustrating. Sent an email to Wahoo today.