Power Match not working well on shorter intervals

Sorry forgot to respond to this Marcus. Yes our power match takes 10-20 seconds to respond. If you are still experiencing this and want to share a screenshot that would help.

Hello Alex,
here are some Screenshots from today.

Yes, I clearly see now. Our power match is really designed for longer steady state intervals. We tried to do one that worked for short intervals but it was too complex for a V1 launch. Kind of like TrainerRoad did we need to build power match 2.0 when we can. Sorry to say but for shorter intervals you need to just turn off power match and make a manual adjustment to your target. We will work on improved power match, but this is very time consuming so will likely not make it into this winter. I wish I had a better answer…

In the shower I had more thoughts :slight_smile: This maybe obvious but if you have any wheel slippage that will cause bigger problems at larger power changes and secondly even with power match you should do a spin down each time you mount your bike and possible each day might help. Another test might be to build slower ramps to bigger power changes. And finally @MedTechCD is a much bigger expert with wheel on trainers then I am and he might have some advice as he had power match working well when he had a wheel on trainer.

Look at the numbers that Powermatch needs to correct. That is your offset at the start of the intervals. That is just the way the actual Powermatch works. It sort of resets at every interval start.
You should really verify your setup because 30w difference is a lot. If you can get your trainer closer to the values of the pedals, you will have a much better experience. I suspect your tire pressure is way too low because your trainer has a much higher resistance then it should and Powermatch has to correct by ~-30W. At lower power values, you may even be hitting the “floor” your trainer can handle at that specific speed and that will throw off Power match completely because it just can’t compensate.
Read through this post and follow the guidelines. It was written for a Tacx Vortex but should apply to any wheel-on trainer.

1 Like


First to my Kickr Snap.
This device is very bad. I used it with zwift and sometimes I was not able to do an interval at ftp for only 8 Minutes. And this time I was calibrating the kickr snap every day (takes about 15 Minutes including device warmup)

After that I bought the GarminVector3 and I see a differece between 20W and 40W between the Destination Power and the real Power.
There was no way to solve the Problem. (Factory Reset, Spindown …)
After only 3 Months this kickr snap hat an Bearing failure and Wahoo was changing it with a new one (i was asking for give it back and buy an kickr core… but wahoo dont like this).

My 2. kickr snap has the same Problem with calibrating.
I use a tire pressure from about 8.5 Bar (~120 PSI). And the screw is fasten 2 x 360 Degree after the wheel has contact to the tire.

Most of time I was using Zwift that handles the Powermatch perfect.

Now to the App.
Yesterday I accidentally leave the Workout during take screenshot. And after that I continue the workout.

  1. Issue
    Today again. Here is the Issue. After that the graphic down in the App differs with the workout.

You can see on the screenshot from Yesterday. At bout 7 Minutes. This not belongs to the Powermatch.

  1. Issue
    The Time (Gesamt) change permanenty for and back during workout (only 2-3 seconds)

  2. Issue
    My 2 hour Workout today goes down to cooldown after about 90 Minutes. (Not in the Graphic, only the Destination-Power… it differs from the Graphic)

The Only Issue I think that belongs to the Powermatch is that the Real Power (Watts) is mostly (about 90% of the workout) higher then the Destination-Power (Ziel). One the Picture here only 10 Watts. but mostly about 10-20 Watts.
Today I Used -10% for the most time of the Workout.

And this may belongs to Powermatch to, at Power change there is sometimes a Peak. Sometimes in the wrong direction to (power should go up, but the Peak goes first down and after that up). On the Picture here es goes up, what is the correct direction

Sorry because of my bad English. I hope you can understand it.


Marcus, the problem with the timer is something else that @Alex can respond to.
I’m coming back to you about calibration for wheel-on trainers.
What you should know:

  • Wheel-on trainers can be consistent if you do it right but usually have low accuracy. Manufacturer specs are somewhere +/-5% - +/- 10%
  • The calibration procedure from the manufacturer will only allow you to get within the above range, but if you have a power meter, you can do better
  • Wheel-on trainers are very dependent on tire pressure and wheel tension. A higher tire pressure results in lower resistance. A higher tension of the roller contacting your tire results in higher resistance
  • Tire pressure changes quite drastically with temperature. This means that riding your trainer at higher resistance creates a temperature change of the air in the tire, pressure rises and resistance lowers.
  • PowerMatch in TrainerDay is not perfect and can’t handle big corrections very well. Alex will surely improve this one day but they have a lot to do and are a small group

If you have already a big “overall” offset on power and then add the power differences caused by the temperature changes, PowerMatch is unable to handle it correctly.
But if you have a Power Meter, you can limit the “overall” difference and then PowerMatch works quite well.

To limit that static difference you need to be consistent and NOT follow the manufacturer’s calibration procedure.

  1. Set your tire pressure at 7 - 7.5 bar. You have it at 8.5 but that is probably a bit high because you set it when cold and it will raise even more once you start riding. Too much pressure causes slippage and then you will tighten the tension too avoid slippage. You will end up with too much resistance…
  2. Turn the tension knob as per instructions from the manufacturer. You mentioned 2 full turns after contact with the tire.
  3. Ride a bit to warmup your tire (yes, it is the tire you are warming up and not the trainer :grinning:). Do some accelerations just to make sure that slippage is minimal. Make adjustments as necessary if there is too much slippage. Lowering pressure a little bit or raising tension slightly will reduce risk of slippage.
  4. Now with this situation, do the Spindown calibration. And this is the ONLY time you should do this unless there were significant changes in your setup. What they call Spindown Calibration is no more then a very awkward way to get you close to the specs. Remember that this is not at all accurate because there is simply nothing to verify accuracy against!
  5. Ride your trainer in high endurance zone for about 10 minutes and then a couple of minutes in low tempo zone while having PowerMatch disabled. On the left you have the target sent to your trainer and on the right the real power measured from the power meter. Check the difference in the last couple minutes at low tempo.
  6. If the power meter is higher then the target, your trainer creates too much resistance and you need to decrease wheel tension a bit. Maybe even raise tire pressure a bit. But be conservative, small changes have a big impact! If power reads lower, you have to do the opposite.
  7. Ride again for 10-15 minutes and check the result. Try to get too a difference smaller then 5W.
  8. And now a very important bit: NEVER do the spindown test again because it will throw of all the work you did above. From now on, try to leave your bike on the trainer as much as possible and check tire pressure before every workout. Be precise! Make a mark on your pressure gauge to match it as close as possible. Make a mark on the tension knob to reproduce the same setting when you remove and reinstall your bike on the trainer.

I know, it seems like a lot of work. But if you do this once at the start of the indoor season, you only have to carefully check tire pressure and wheel tension before starting your workout. Just hop on and and after roughly 10 minutes of warm-up, your power values will be close. PowerMatch will do the rest and compensate little differences caused by temperature drift. During you ride (after warmup) you should never see corrections higher then about 10W.
Let me know how things went! :smiley:

Oh I see. So the power problem might be with time. Or first before looking at power problems you need to fix the timing. The timing is because your phone is too slow (our app requires a faster phone). Restart your phone and limit background tasks is first.

What phone and version of Android are you using?

Hi Alex usually there is no Problem with timing. It’s only if I leave the Workout and Continue after that. Then the Timer go’s maybe 4 sec for and the 2 back every second…

At the End of my workout Today the Timer was on 1:30. But after Upload to Strava I can see thats about 2 hours… (It should be 2 Hours too. So the Timer was wrong)

I use a Doogee S58 Pro with 6 GBRam and Android 10

I will send you direct message on how we can work on this.

Also your English is fine. Most of our customers are from Germany, Spain and Italy so not many natives English speakers here :slight_smile:

There is something wrong here. The Ziel/Target says 150, but the graph at the bottom is showing about 185. This is a problem. Let me send this to my developer.

Yes that is the Problem. After I leave the Workout and continue.

Some months ago I got a phone call during workout and after that continue the workout. And I had the same Problem.
I think the app does the Workout correct, but the graph dont matches… its shifted. In my workout today the graph was shifted about 30 min.
Today the TargetPower goes to 92 Watts for cooldown but the graph was at about 170W. The Time (Gesamt) was at 1:30, but the workout was about 1:55 (cooldown, i see that on my strava upload)

Oh I see. I am sure this is a performance problem with your phone (and our app). After the winter we plan on working on performance but this is a complex task. So you have multiple problems. The problem it is hard to understand them since they mix together. If you do steady interval and do not put you phone in the background is the power / power match correct? It sounded like you said it is 10-20watts wrong but I have not seen this in your screenshots.

@Alex Yesterday i had a problem too. Caused by a Whatsapp message coming in. The incoming message makes the TrainerDay app pause the workout. I didn’t notice it right away because I had Fatmaxxer running in the foreground and TrainerDay in the background.
Seems like you need to check the continuity off the app when other things happen on the phone.

Crap. Our tester had mentioned he saw this before too but he always sees things no one else does… :slight_smile: So I had not prioritized it yet. We will look at this ASAP now that i understand the problem. This seems to be an Android only problem.

today I was tuning my setup a little bit. Like MedTechCD mentioned.
The Powermatch difference is now much smaller. But at Powerchange
the first 3-4 seconds are sometimes a little bit heavy…
And if I go out of the saddle, my tire is slipping now… but that I have not to do for TrainerDay workout. so its ok.

Here a Screenshot

This is looking way better. Glad to hear. Yes our app takes 10-20 seconds to react to power changes and your trainer might be overshooting these targets as well. Someday we need to create a new version of power match that works with short intervals. You could change your workouts to ramp starts and see if that helps. Let me know if you need me to visually explain what I mean by ramp starts.

Hi there, just wanted to vote for a Powermatch 2.0, would be (for me personally) the best improvement to the wonderful app. I need Powermatch since my good ol Neo gen. 1 is a bit too harsh on me with the power numbers and I want a consistent experience with my outdoor powermeter. Right now I need to switch off powermatching for short intervals (and then reduce the workout intensity) which is a bit annoying……

Thanks Felix, yes I know Power Match 2.0 is desperately needed for people doing hard intervals. For most people I just suggest to turn it off on these hard intervals. We will definitely do a 2.0 version I am just not sure how soon.