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PowerMatch: Using Power Meters with Electronic Trainers

PowerMatch is a feature from TrainerRoad that allows you to use your power meters to control the resistance on your electronic trainer. Additionally, you can manually adjust the power readings on your electronic trainer to more accurately measure power while you train. 


How PowerMatch Works

PowerMatch allows riders to display and record power readings from their power meter and still benefit from the automatic resistance control of their electronic trainer. It lets riders get consistent power readings from their power meter both indoors and outdoors without having to give up the benefits of their electronic trainer.

Put simply, PowerMatch will use the power readings from your power meter to control your electronic trainer. TrainerRoad will measure the power offset between your power meter and electronic trainer and will adjust the resistance of your electronic trainer based on that offset in power and the current interval target.

PowerMatch will work with any electronic trainer that works in ERG mode with TrainerRoad.

What is the "power offset" you're talking about?

The reality of the power-device world is that different devices will often display discrepancies in their readings. For example, an output of 200 watts on a power meter may equate to an output of 220 watts on an electronic trainer. These two devices would have an offset of 20 watts at that level of output.

PowerMatch effectively neutralizes this offset. 

Using PowerMatch with iOS

TrainerRoad's default PowerMatch setting is to use the power from the power meter to control the electronic trainer's resistance. Simply pair the power meter and electronic trainer, make sure PowerMatch is set to "Auto", and TrainerRoad will take care of the rest!

Note that the power meter will display as your power source in your Online Career.

Additionally, the offset between the power meter and electronic trainer will be measured and adjusted (if necessary) every ten seconds as per the default settings.

 

Disabling PowerMatch

If you wish to disable PowerMatch, you may do so within the pairing screen of your electronic trainer.

Disabling PowerMatch will prompt TrainerRoad to display and record power readings from your power meter both a power meter and electronic trainer are paired at the same time.  ERG mode is still available; however, the electronic trainer will use it's own power data to calculate resistance instead of the data from your power meter. If there is a discrepancy in power readings between the electronic trainer and power meter, disabling PowerMatch can make it look like you are constantly above or below the power target. 

Currently, the option to "use cadence only" from a power meter is not available in iOS. 

 

 

Apply Consistent Offset Between Trainer/Power Meter

If you know the power offset between your trainer and power meter and do not wish for TrainerRoad to continuously measure and adjust this, you can input this offset to be applied to the entire workout. You can do this within the pairing screen of your electronic trainer.

 

Using PowerMatch with Desktop

TrainerRoad's default PowerMatch setting is to use the power from the power meter to control the electronic trainer's resistance. Simply pair the power meter and electronic trainer, and TrainerRoad will take care of the rest.

Note that the power meter will display as your power source in your Online Career.

Additionally, the offset between the power meter and electronic trainer will be measured and adjusted (if necessary) every ten seconds as per the default settings.

If you wish to disable PowerMatch or apply a consistent offset, you may do so under your Profile tab.

Disabling PowerMatch will prompt TrainerRoad to display & record power readings from the power meter if both a power meter and electronic trainer are paired at the same time. According to our device paring hierarchy, the power meter will take precedence over the trainer.

If you don't want to use PowerMatch, and you'd like power readings from only your electronic trainer, unpair your power meter.

If you know the power offset between your trainer and power meter and do not wish for TrainerRoad to continuously measure and adjust this, you can input this offset to be applied to the entire workout.


Why Does My Power Appear Less Smooth with PowerMatch Applied?

Those well-versed in electronic trainer usage will be very familiar with the smooth nature of graphed power in ERG mode. This power appears so smooth primarily because of natural smoothing that the sizable flywheels of many electronic trainers applies.

Many strain-gauge power meters measure power directly from the pedal, crank arm, or crank. This method of measuring power is more sensitive than what most electronic trainers use, and thus, even riders with the smoothest pedalstrokes will notice "jumpier" power readings. This is nothing to worry about so long as the fluctuations are not drastic.

Power Graphed with only Electronic Trainer

Power Graphed with PowerMatch (Electronic Trainer + Power Meter)

Despite these graphs appearing sightly different, both users got the same training benefit from these intervals. The top profile simply doesn't represent the actual fluctuations in power as clearly as the bottom.

Have more questions? Submit a request

Comments

  • Avatar
    Mark Hodos

    I think this mode should be called "Cadence Mode". I have a Power2Max Type S power meter and a Wahoo Kickr. In the old mode, I would use the Kickr as both ERG and power meter, and I would pair my power meter so that I got cadence from the power meter. This was great as it forced me to do the intervals correctly, and the Kickr's response to changing cadence was almost instantaneous, keeping me at my watt target no matter how fast I pedaled (which is what an ergometer is supposed to do). I noticed it was even more accurate if I kept myself in a high gear and thus caused the Kickr's flywheel to spin faster.

    Today, I updated my software, and this PowerMatch nonsense is enabled. The problem I have with it is this sentence from your documentation above "Additionally, the offset between the power meter and electronic trainer will be measured and adjusted (if necessary) every ten seconds as per the default settings." As best as I can tell from the ride I just did, this means that every ten seconds, it takes a snapshot of my cadence and what my power meter says, and then tries to make the Kickr resist the correct amount for the next ten seconds. The problem with this is that it only works well when your cadence is already at the target cadence of whatever Sufferfest etc calls for in that interval. If the cadence is too low when the sample is taken, and then you speed up to the target cadence, for the next 10 seconds you are pushing a LOT more watts. (~100 watts more in some cases when you have to all of a sudden sprint at 100rpm from 80 or 90 rpm). The old way used to catch up in at most 2 seconds. The upshot of this is that I end up putting out too many watts for like 8 of the 10 seconds, then I get tired and slow down, then the thing takes another sample, then I speed up again and end up overdoing it. It's like an oscillation of too much power and not enough.

    So, how is it that in the graphs above, both users got the same training benefit from the intervals? If you average the powers shown for an interval in those two graphs, it will not be the same, so how is it the same? And with a 10 second delay, you'll miss shorter intervals entirely. I don't think it's that it doesn't represent the power fluctuations as clearly as you say because one is checking every 10 seconds and one is checking much more frequently.

    So, what to do? Well, I could go back to just using the Kickr, which I tried, except that I pair my power meter to get cadence. Now, I can't do that anymore as the power meter takes precedence and I end up in this stupid mode again. I suppose I could use my Garmin for cadence, but then it won't get recorded with the trainerroad ride.

    Or, I just use this mode and live with the fact that I no longer get to watch the sufferfest video because I have my eyes glued to the cadence reading so I don't mess it up. Or is that I suck and I should have a completely steady cadence even when I'm getting hammered by Sufferfest?

    Please tell me how to set this up so either it's like the old way and I can get cadence from my power meter, or make the 10 second interval much shorter (though there's probably a reason why you guys made it ten seconds ... maybe it stutters when it's shorter?)

  • Avatar
    Ryan McNally

    @Kevin: I just replied to your email regarding this! :)

  • Avatar
    Steve Rodgers

    How does the offset work? There is something like a 10% difference between the Tacx Bushido Smart numbers I'm seeing and the Vector S I have (latter is higher). This is a scaling thing not a fixed number. If the offset is a number (eg 40 watts) things will line up reasonably well at just above threshold but degrade in agreement above or below this. (And I presume an offset of 40 watts wouldn't result in a minus 40 reported on the trainer when there's no power?) just me... Or would a offset by % option be a useful addition?

  • Avatar
    dan Streetman

    I love the direction that PowerMatch is headed, but I have to agree with Mark Hodos: the delay in adjustment makes the power required by the KICKR far more variable and delayed. I feel very pronounced spikes/lulls that last longer than before. Is there really a 10 second interval between adjustments? The in-context documentation notes that this will improve over time, but I'm not feeling it. Love my KICKR and my Quarq...just looking for a way for them to co-exist peacefully!

  • Avatar
    Alexander Hem

    I agree with dan Streetman about th e direction PowerMatch is heading. However, I am having the same problem as Mark Hodos with the exact same set-up. Are there any planned updates that could fix the problem?

  • Avatar
    Dayton Adams

    @dan @Alexander: Here was Ryan's reply to Mark Hodos.

    "So let's see if we can get things working for you better and clarify a few things for you regarding the new PowerMatch feature. First off, I do want apologize if the support article wasn't clear enough!

    So first off, addressing this sentence: "Additionally, the offset between the power meter and electronic trainer will be measured and adjusted (if necessary) every ten seconds as per the default settings". What this means is that every 10 seconds the Kickr is checking in with the power meter to make sure that it's power is correct. However, the Kickr will still be adjusting to your cadence just as it has done in the past. It is important to note, as you mentioned, that there has always been a 2-3 second delay with the Kickr adjusting it's resistance to your cadence and power output. So PowerMatch doesn't actually make it adjust to your cadence less often and the 10 seconds statistic is just referring to the calibration between the Kickr and power meter.

    Secondly, regarding the difference between the two graphs in the support article, that's an example actually from the same ride. What you're seeing is the difference between how a power meter and Kickr output power. The Kickr outputs power smoothed, meaning that it's a smoothed 3 second average that makes it look nicer to view. However, it's not necessarily representative of what your instantaneous power output is without power smoothing, which is what you then see in the graph from the power meter. So the point is that it is the same intensity of workout, just that your data will be more accurate and thus look different."

    That said, we do realize that, like all new features, PowerMatch need's to be tweaked here and there and our developers are currently working on improving things with our ongoing desktop revamp.

    Hopefully this clears some things up. :)

  • Avatar
    dan Streetman

    Thanks for all that background! Makes more sense. I must say that it certainly FEELS like there is more of a lag between adjustments when I'm using Quarq power versus when I use only KICKR power as the input. Looks like everyone else has the same feedback.

    I believe it will be a very cool feature once it's dialed-in. For now, I am leaning towards disabling it and just use my garmin kit to record the ride data.

  • Avatar
    Mark Hodos

    @dan @alexander

    Sorry for not responding sooner. In short, I've been doing my riding outside lately, though I'm due for another Sufferfest soon. The Trainerroad support team were excellent, followed up with me 2 or 3 times, very on top of it and helpful. From what I could gather, power2max reading + kickr resisting is EXACTLY the same as kickr reading + kickr resisting. Not sure if I believe it completely, but I am willing to tentatively chalk it up to a perception issue from looking at power data all over the place -- i.e. it's the same underneath, but since the power is now spiky and all over the place, the cadence having to be spot on is a little dissonant and so my mind is playing games with me? I dunno, but since there's no way to go back, it is what it is I suppose.

    Does anyone have any tips for not having to keep my eyes glued to the cadence so that I don't drop? Even if it's psychological, it's a big difference to have the kickr either letting you spin too much or resisting too much. One thing I liked about the old way (kickr reading and resisting both) was that I could slack off on cadence if I wanted and still be locked to the ergometer, so I at least felt like I was getting the workout.

    Maybe I just need to practice more with this the new way, or if I lose cadence, just resign myself to have my cadence targets accuracy thing way off.

    @Dan, if you let the Garmin do all the recording, are you saying that you would tell it you have no power meter and let it do kickr reading + kickr resisting? If so, I suppose you're resigned to not have cadence on the Trainerroad file because you're uploading the garmin file to Strava or whatever so it doesn't matter? Just trying to figure out what you're doing as it doesn't sound like a bad idea.

    For what it's worth, I tried doing power2max reading + kickr resisting in Zwift, and it was the same deal .... oscillating resistance, laggy, etc, so I went back to kickr reading + kickr resisting + powermax for cadence, which thankfully was still available.

  • Avatar
    dan Streetman

    @Mark,

    Thanks. When I use my garmin 920 or 510, I just watch power, cadence, etc on the head-end ignore the kickr data. Then I use Garmin connect to upload the data wherever I want to send it. I don't do sufferfest or any videos and just just have my own custom workouts for IM and LC Triathlon training (where steady, smooth power is important)

    I find that the KICKR and Quarq aren't usually too far off, so the power I program into TR is good enough to be close...but I've yet to have them be 100% consistent. I find I'm preferring a "smooth" ride that's close to power than a 100% accurate power setting that feels jerky.

    Again, love the idea of PowerMatch...just not sure we're close enough in V1 to "enjoy" a smooth ride.

  • Avatar
    Mark Hodos

    @Dan,

    Thanks. I also find that my power2max and kickr are usually quite close (they are certainly within 5 or 10 watts of each other at ~250 - ~300+ watts where I care about it), so while I applaud that Trainerroad is trying to give us even more accuracy, I'm ok being a little off as it's expected. I'm nowhere near good enough to notice or suffer the difference, that's for sure. I'm gonna try using my 800 to record data.

    @trainerroad support
    As per the issue, to quote Trainerroad support:

    "The Kickr outputs power smoothed, meaning that it's a smoothed 3 second average that makes it look nicer to view. However, it's not necessarily representative of what your instantaneous power output is without power smoothing, which is what you then see in the graph from the power meter. So the point is that it is the same intensity of workout, just that your data will be more accurate and thus look different."

    I'll bet it's a data aliasing issue -- since the power data from our meters is more spiky, not only is it more "accurate", but it's being sampled at a much higher rate (hence the spiky nature of the graph), so if i softpedal a half turn of the cranks, and that happens to be when it measures, compared to Kickr's smoothed data, there's going to be a big delta, and it's going to be jerky trying to catch up.

    So, in reality, even though the data is more accurate, it makes us less precise in our rides. (underlying all of this discussion is an "accuracy" vs "precision" conflation). Smoothing the data is, in effect, making it more "precise" because the values end up closer to each other. Obviously, this is the knob the developers have to turn to hit the sweet spot (which, in my opinion, was probably very close to where the Kickr was initially -- the Kickr likely being the lowest common denominator as it has the most smoothed data).

    My thought is that in order for this PowerMatch idea to work, the smoothing would have to be the same on the reading, the resisting, AND the display so that the rider has a chance of knowing what's happening at the same rate/smoothing that it is actually happening underneath the covers.

    Whilst having snazzy spiky time-series graphs of instantaneous power look awesome to the uninitiated, I don't think we humans can react fast enough to use it, and in the end, it's nowhere near as useful as the smoothed data. It's very tempting when looking at performance data to want the most "accuracy", but what we are really looking for is usefulness (precision).

    (sorry for all the edits to this post while I get my thoughts sorted)

  • Avatar
    Alexander Hem

    @Dayton: Thanks for the update. It does clarify a few things, however, like Dan says, it does feel like there is some lag compared to the experience when it is the Kickr/TrainerRoad interaction controlling the resistance.

    That being said, I do love the idea of PowerMatch as my power2max (as compared to Mark's) have a larger offset compared to the Kickr power data and using the power meter data to control resistance for intervals would be great.

    On another note: I am also having trouble doing spindowns when my power meter is controlling the resistance. Is this a known problem, or just my Kickr acting up?

    With regard to the desktop revamp, is there any preliminary release date?

  • Avatar
    Mark Hodos

    @alexander

    That's a real bummer that the power is so off on your Kickr. I'm sure you probably have already, but did you upgrade the Kickr to the latest firmware?

  • Avatar
    Alexander Hem

    @Mark

    Indeed, that is why I am such a fan of the PowerMatch idea ;) I have the latest firmware and have also calibrated the Kickr using Wahoo's calibration kit.

  • Avatar
    Mark Hodos

    @Alexander

    Gotcha. I didn't know the kickr had a calibration kit/app, just googled it. Awesome.

  • Avatar
    Robert Libralon

    I can not get the offset to work! I'm using iPad mini2 connect via BT to my kickr. I need a 21W offset so that trainerroad reads = to stages PM as at the moment TR reads to high. But it makes no difference, I could put +100 or - 100 and my stages power is still 20W off. TR control the kickr as per normal but the offset is not applied. Please help

  • Avatar
    Alexander Hem

    Short update:

    It seems like some of my problems were related to the optical sensor on my Kickr. Wahoo sent me a new sensor and the power matching is working a lot better. My Kickr and power meter is also tracking more consistently.

  • Avatar
    John Coyle

    I am considering trying this with my new Tacx Bushido. I am new to the whole ERG thing. Any guidance/warnings!

  • Avatar
    Jim Daley

    I'm new to Trainer Road and trying to figure this out. I did a ride today with PowerMatch on. I have a Powertap and Tacx Vortex Smart. I also had my Garmin 520 on the bike. The watts on the Garmin seemed to be constantly about 15 watts off from what Trainer Road was showing for power on my computer screen. Why is that? I think PowerMatch should have made them much closer than they were??

    Also, I am confused by this statement in the documentation above:

    "Disabling PowerMatch will prompt TrainerRoad to display & record power readings from the power meter if both a power meter and electronic trainer are paired at the same time. According to our device paring hierarchy, the power meter will take precedence over the trainer."

    I thought that's how it would work with PowerMatch on? What exactly does PowerMatch do in addition to that? Will the power meter's power still be used to control the trainer's resistance if I turn PowerMatch off?

    Thanks!

  • Avatar
    ross fripp
    @ Alexander Hem How are you getting on with this now? If you ignore the watts readings (which will appear to fluctuate more as the data is being collected at more frequent intervals).... In terms of altering your cadence and changing watts for efforts (eg going from 180W at 90rpm the same 180W at 110rpm... Or a sudden change for an interval like 130W 85rpm to 300W at 90rpm) is the kickr as quick to respond and does it feel as it did when you were using just the kickr? I use a garmin cadence sensor for cadence but just got a power 2 max type S fitted and won't be trying it out until wedn (FTP test!) Thanks in advance
  • Avatar
    David Tuttle

    I am glad that you explained this, as I just set up my Pioneer Power Meter & did Rubber Glove so I would have a proper FTP with the new PM, I was concerned about the fluctuations vs the VERY smooth Wahoo readings I've gotten over the last year. Not now and I can move forward with indoor/outdoor training and using one Power Meter and not worried about the discrepancies.

  • Avatar
    matt thompson

    My stages reads 40 watts lower on my garmin then trainer road reads with my power beam pro. 40 watts is hug. How do I fix this

  • Avatar
    Carlo Malana

    This is my second Wahoo Kickr (I had the original and got tired of having it all over the place with TrainerRoad and went back to my Kurt Kinetic). I decided that over a year later, I would try it again with a KICKR Snap but I still have the same result. Resistance is all over the place with the slightest change in cadence and doing short sprint intervals (like 20-30 seconds are impossible as the resistance would increase to over 100+ watts over the target, then I can't keep up the effort so cadence drops, and then resistance gets added even more, and then I have to wait until it is zero and I can pedal again). I can't use an offset as the difference changes and is not consistent (during easier intervals, resistance is too low, and then during higher intervals, it is higher). I tried using PowerMatch and same results and resistance doesn't adjust very quickly. Surely there has to be a way to fix this?

  • Avatar
    ross fripp

    Carlo Malaga - what power meter are you using to try and pair with your kickr? I use a kickr with a p2m power meter and have absolutely no issues at all, so I suspect it's something wrong with your set up. Just to check it's definitely power match not working, try disabling it and seeing what happens with the intervals then. It may be a poor ant+ connection.

  • Avatar
    Robert Libralon

    If trainerroad sample the external power meter during the ramp period to next segment it will add an incorrect offset due to different power filter time. TraIt should only

  • Avatar
    Robert Libralon

    Oops pressed add comment by mistake :(
    * Trainerroad should only add an offset during the dwell period of the segment's

  • Avatar
    Russell Gelhorn

    Is this feature being actively worked on? I find that Power Match is very slow to adjust resistance when going from a recovery period into the next interval. If the interval demands 200w power, it will start around 140w and slowly adjust over 2 minutes up to the correct 200w. If it is a short interval this can be a big problem. Only workaround I've been able to find is to stop at the start of each interval and then start again, forcing Power Match to reset.

    My setup:
    - Tacx Vortex Smart
    - 4iiii Power Meter
    - Using the new TrainerRoad app on Windows 10.

  • Avatar
    matt thompson

    my G3 hub reads 70 watts lower then my powerbeam pro, but power match has seemed to fix it. I think its the trainer manufactures that need to deliver what they promise accuracy wise

  • Avatar
    Bodo Knudsen

    On the last podcast there was a brief mention that Power Match was working much better on the new Kickr. Curious to hear if anyone has tried it both on the original Kickr and now the newly updated one, and if so, was there a big improvement?

  • Avatar
    Nicolai Handevitt-Haar

    I have started using powermatch with my Kickr and Stages pm combo as I was being supplied with overly optimistic FTP figures from the Kickr's inbuilt PM. I took me by surprise it was as much as 30Watts over what the stages was reporting, yep ego in tatters it was time to get real. On the subject of lag using powermatch I have found that if you spin the Kickr up in the big chain ring and small cog at the back there seems to be a substantial lag for the power to adjust. In fact on shorter high wattage intervals I was sometimes hung out to die when the power simply didn't come down for 20~30 seconds after the interval was done. Now I use the small chainring with a middle gear on your cluster, the result is much quicker reactions from the power tracking to intervals.....works great now, and I can train outside & inside with identical numbers..finally

  • Avatar
    Bryce Lewis

    Hey Nicolai,

    I'm glad to hear you worked things out for you!

    We too have found that a smaller gear equates to a much faster ERG response, and that is something that will benefit all users with smart trainers but especially PowerMatch users.

    As always, if you are every experiencing any difficulty with TrainerRoad, don't hesitate to reach out to us at support@trainerroad.com and we'll be happy to lead you in the right direction :)

    Cheers!

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