Kickr Core maybe it’s me...?

trainer

#21

my understanding is that TR app is receiving data from both Kickr and crank/spider/pedal power meters, and then controlling Kickr power based on difference.

Given the example above where Kickr went from -13 W to +6 W, it seems to explain that one workout where it felt like TR’s PowerMatch was fighting with itself for half of the workout.

I used TR PowerMatch for over 6 months, and agree it worked very well except for one workout. And that is why I’ve been using Wahoo’s match (control w/ANT+) for the last 5 weeks. But that is not foolproof either, sometimes the Kickr doesn’t connect with Stages (about 1 out of 10 workouts in my limited testing).


#22

I use powermatch in TR but also have the box checked in the wahoo kickr settings to “Use ANT+ sensor” - this made a noticeable improvement when I checked it.

I find that I also need to do a spindown about once a week due to power reading super low. As soon as I do the spin down, calibrate my Stages L/R, and reboot TR, the power reads normal again.


#23

This slightly differs from my understanding - although whether or not you calibrate should be largely irrelevant either way.

Without getting into the the technical differences between how it works and how you describe it…here is why I think the calibration frequency or even overall accuracy of the trainer matters with power match.

Essentially calibration of a kickr is handled via a spin down, which is measuring the resistance applied by the belts in the system - it then applies this as an offset to build the entire power curve. It doesn’t do anything that would change the slope of that curve, just the height of it from zero (could be positive or negative depending on the spin down results).

What powermatch does is receive the power from the power source being used as a primary source (either the trainer or a separate power meter would use the same principle) and then adjusts the resistance based on that number compared to the target power.

So if the power source is 305 and the power target is 300 watts the application will transmit - reduce resistance by 5 watts. It doesn’t matter if the power source is the kickr or the power meter - the application is doing the same thing.

Some people struggle with power match not because the software takes more time to calculate this data or that the math is more complex - it is that the power readings are coming from closer to the power source so can be much spikier. This is particularly true for single sided power meters where the power meter itself is doing some math and smoothing to calculate total power (even more pronounced at lower cadences) and at pedal based power meters which tend to have the quickest response time since they are right at the dang foot.

So back to the original calibration or not issue - if you are using power match it doesn’t matter at all what power the trainer is transmitting. The adjustments will be based upon your power meter either way. If the trainer registers 455 watts, the power meter 305, and the target is 300 the application will just say reduce power by 5 watts and constantly fine tune to keep your power meter readings at the target number


#24

Its right here https://support.trainerroad.com/hc/en-us/articles/204631294-PowerMatch-Using-Power-Meters-with-Smart-Trainers

“TrainerRoad will measure the power offset between your power meter and smart trainer and will adjust the resistance of your smart trainer based on that offset in power and the current interval target.”

I’m an engineer and in the past (20 years ago) worked on control algorithms. By no means an expert, but the TR support article matches with my assumptions based on rusty knowledge of control algorithms.


#25

I guess it depends on how you interpret that. I don’t take that to mean that different calibrations will meaningfully change the experience you get with power match.

I do not think that means that the offset matters at all - it is measured and then adjustments are made based on that. If the offset is -50 watts, +5 watts or +500 watts the software is doing exactly the same thing. The calibration of your trainer should be completely immaterial to the performance of power match


#26

sure, agree with you on that when using TR’s PowerMatch - every 10 seconds it takes Kickr power output, compares to your PM output, and adjusts resistance of smart training accordingly. So even if Kickr is slowly drifting as it gets warmer (or whatever), that will get tracked and taken care of every 10 seconds.

The one or two weird issues I’ve seen in the past were due to dropouts.


#27

Day 2 update with some interesting things. This is all getting over my head. My units serial # is definitely a fresh new unit.

Good news is any noises and smells I had Day 1 have cleared up once broken in.

Yesterday I did a advanced calibration and this greatly closed the wattage gap between the Core and my PM within about 8 watts(still low). I didn’t do any interval testing to compare(just visual).
So today I did Hunter which is 20 min SS intervals. I changed my settings to this:
Wahoo App
Erg Mode Speed Simulation OFF
Erg Mode Power Smoothing OFF
Control w/Ant+ PM ON

TR App
Erg Mode On
Power Match OFF
Cadence Using PM ON

These settings completely smoothed out Erg mode for me. It held just about as smooth as I could ever ask. It was a night and day difference from yesterday. All the intervals ended AT or -1 of prescribed wattage. BUT it felt just a touch easy so I raised intensity 3-5%. So I turned on my Garmin and started reading the power coming from my PM and when I hit the lap button I consistently got 5-8 watts lower watt avg. than what TR said I was averaging. This makes me wonder if using the PM Ant+ solves nothing. It makes no sense to me. I’m going to test this again tomorrow.


#28

I’m seeing the same with Control w/ANT+ setting. I’m going to disable that, and turn on TR power match.


#29

Just got mine last weekend. Running Stages and Kickr Core concurrently and I have about a 20-25% difference in wattage reported - with Core running low. Did several spindowns and it did nothing.

Attempted a zwift workout in erg mode and at a few points, could not even turn the cranks for what was supposed to be 140 watt interval (warmup). My serial number is 40184000307 so not sure how to interpret that based on above.


#30

That’s very disappointing and starting to sound common. I wonder how many don’t ever know.


#31

Interesting video by GPLama testing Wahoo using Ant+. I’m going to keep using that method and compare results for a few rides then maybe switch to another method and try that…

#32

I’m facing similar issues as you where the power difference was roughly 50 watts lower as compared to my Quarq. Nothing improved after warming up 10-15 mins and my spindown timings were in the range of 8-9.5 secs.

While using power match would solve the issue, the Quarq is on my outdoor bike and it would totally defeat the point of having a dedicated indoor setup so that I don’t have keep moving my setup.


#33

I did the exact same for test3, except using TrainerRoad (vs Zwift) and Stages LR (vs PowerTap p1). Even using a Garmin Edge 520. Here is the disappointing results from last workout:


(15sec smoothing in DCRainmaker analyze tool to make it easier to see)

You can see Kickr is usually 6-10W higher throughout the 80 minute workout. I called Wahoo support and reported, they kinda shrugged. Hmm. I’ll paraphrase, they said Control w/ANT+ is beta as you can only set it using iOS app.

I’ll try a couple more times, and then I’ll go back to using TrainerRoad’s PowerMatch.


#34

Thanks for sharing that. So in this test the Kickr read high or low?


#35

I’m going to try DC’s comparison tool tomorrow.


#36

In this test the Kickr was 6-10W higher than Stages LR. I have other tests where it went from lower to higher, and other tests where it was perfectly well behaved (within 3 watts).


#37

I emailed tech support with the discrepancy. Sounds like our power is off by similar amounts. Its not a huge deal for me because all my bikes all have power meters, but still annoying. And does that mean ERG modes will not work if using power from Stages instead of Kickr? Ive never used ERG mode before (came from a dumb trainer) so not sure how much of a difference Id feel about it for intervals.


#38

Hopefully tonight I can do a power comparison and get a good look at things. Not so Quick update.
Day one settings:
Wahoo App
Erg Mode Speed Simulation ON
Erg Mode Power Smoothing OFF
Control w/Ant+ OFF

TR App
Erg Mode ON
Power Match ON
Cadence Using PM ON
I was new to Erg mode so I need to go back to this and see if it was me but the watts were ALL over the place. Every interval finished below prescribed wattage. Not what I expected. And at the time the trainer was reading around 30 watts low.

Day 2 settings.
Wahoo App
Erg Mode Speed Simulation OFF
Erg Mode Power Smoothing OFF
Control w/Ant+ PM ON

TR App
Erg Mode ON
Power Match OFF
Cadence Using PM ON
After Advanced Calibration. These settings were SUPER smooth just as I’d expect. If all rides were like this I’d be a happy dude. Except the average watts per interval TR displayed did not match what my Garmin displayed. About 6 watts lower on Garmin using PM readings only. I bumped up the intensity to counter it.

Day 3 settings:
Wahoo App
Erg Mode Speed Simulation OFF
Erg Mode Power Smoothing OFF
Control w/Ant+ PM ON

TR App
Erg Mode On
Power Match ON
Cadence Using PM ON
So basically this setting has the trainer supposedly using my PM as power source and on top of that TR is power matching. This was not half as smooth as Day 2 but I was finishing intervals just about right at prescribed wattage. Then it started reading really high at times and 3/4 way into workout what was supposed to be sweet spot was at threshold. Then it cleared up and went back to normal but still not very smooth. The watts did match my Garmin readings using just PM. So wattage accuracy was the best in this case but harder to keep consistent and at times got out of control. Day 4 I’ll try a different setup until I’m happy. I also plan to compare power and look over workouts in detail when I have more time.


#39

I just read through all the comments in the video I linked to earlier and 2 people said Wahoo told them Ant+ for power only works while in the Wahoo app. Might work if left open.