Power Matching for ERG Mode

Can we get support for power matching when using ERG mode?

Meaning app will use our third party power meter as the source (ignore trainer's power meter) to reach the target power and control the trainer’s resistance accordingly.

Right now I'm having to use my expensive smart trainer as I would a dumb trainer. It's frustrating. I want it to auto control the resistance and give me ERG mode but also read from my power meter which I also use for outdoors training (for the sake of consistency)

I've checked another older post on this subject in which a rep said it was in the menu for 2018. Well, the year is almost coming to a close. As a new subscriber who really enjoys the app, I don't want to have to move on to other platforms where I can better utilize all my gear. This feature is CRUCIAL. Come on guys...



  • I am trying to switch from Zwift to The Sufferfest (TSF), but this is a feature I've always used in Zwift and would really like to see it in the app. There is about a 10-12 watt difference between my crank based RotoR power meter and the Tacx smart trainer I have. I'd need to manually play with my FTP or 4dp values to match power output for outdoor rides.

    The compelling feature for me to come to TSF is that outdoor rides are a first class citizen as opposed to TrainerRoad.

    Posting a comment here to be notified when this feature is in the app.

  • If you have a KICKR you can backdoor a power match feature. In the Wahoo Fitness app, select your Kickr, then enable "Control w/ANT+ Power meter" option and then select the ANT+ ID for your on-bike power meter. In this way, I'm able to use my QUARQ power meter to provide power data feedback to the Kickr. Works great and seems to have the same end result as using power matching directly via the app (the way it works in Trainerroad, for example).

  • Ok-I have a SNAP.  But this won't work unless you have an ANT key for your phone, right? What if you're using a laptop w/ant key?  How would you do this?  (Can't believe it's taken them this long to implement something that other platforms have now had for years).

  • I am using a PC-laptop with an ANT dongle and no ANT key for the phone. The step by step for me to get this to work with my KICKR was as follows

    1) Enable bluetooth on your phone and open up the Wahoo Fitness App

    2) Find your KICKR inside the Sensors menu, select it.

    3) Enable the "Control w/ANT+ Power Meter" option. Be sure that you enter your ANT+ ID from your on-bike power meter

    4) Do a spindown (not sure if this really matters, but it can't hurt)

    5) Inside the Sufferfest app, use the KICKR as the power data source and use your power meter as the cadence source only. Note that if you select your power meter as the power source it breaks the workaround

    In reality now, your power meter will provide the feedback loop to the KICKR (outside of the SF app), but the SF app will "talk" to the Kickr to give power targets. The Kickr will also report power (as measured by your power meter) back to SF app.

    Sorry I can't provide SNAP trainer specific info, but the general process hopefully is applicable to other models.

    On an ongoing basis, you do not need to have the Wahoo Fitness app open on your phone (and in fact, I'd recommend not having it active at all to avoid any possibility for 2 apps trying to control the Kickr at the same time)

  • Tried the above on the kickr but didn't work.  Frustrating that sufferfest has yet to implement this feature. Been using sufferfest for 4 yrs.  Will get rid of my inaccurate kickr or finally move to another platform.

  • I would really appreciate not having to play with my intensity numbers to have an accurate workout. It’s quite annoying to not have power matching. It’s one of the only things that keeps me using Zwift as well

  • I was expecting this to be the norm, fortunately I have a Kickr so ill be using that work-a-round. Hopefully it still works, cheers Ken Bayne.

  • How come no-one from The Sufferfest has replied to this?  Anyone know if their staff read this section?  I too remember saying that it was on their to-do list for 2018.

    I have a Tacx Vortex with Garmin pedals.  If a calibrate normally, then the two are well over 10% part.  Pedals say 260W, Tacx says 290W+.  I can cheat the calibration to get them to match, but then it goes way off as the trainer and tyre warm up.  by the end of a session they're miles apart again.  

    If not power-matching, then an on-screen, in -app calibration thing would be nice.  When my trainer tells the app is producing say 290w of resistance, I want to be able to tell the app "no, that's actually 260w".  Then I can train on my trainer without having to use the power meter, knowing the trainer and app are producing realistic numbers.

  • Hi Everyone!

    Power match is coming.  If you look at the 6.0 app you will notice that our method for device connections has changed.  One of the main reasons for this is so that we can get this moving.  I can't give a timeline yet....still.... I know (I want it just as bad as all of you here). 


    I promise though, it is coming, and I'll keep bothering the SUF team about it until it is here.

  • Good to know it's coming...


    Will try the power match again.  I tried a few months ago but was unsuccessful.  Just didn't seem to be anywhere near the stages output on my Garmin.


    With my kickr the resistance appears to increase as the unit warms up.  I keep it in the house now, next to a radiator so it's a bit warmer than the 0 degrees that it would be in the shed.     Starting then around 20 degrees and having done a spin down we're fairly accurate, but 15 minutes into the workout the temp has risen and so has the resistance - leading to about 10-15% extra based on stages (and legs!).

    This is pretty brutal at prescribed 350-400w!!   Does mean that I have issues completing workouts - or I need to adjust down the dials, and who likes doing that!!


    Have a couple of days before the Tour, so will have a play and see if I can get it right...

  • Relieved to see this - I thought I was doing something wrong.  I have a Kinetic Smart Control and I use both the Kinetic Fit app and Sufferfest in my training plan.  They use the same trainer but the power readings between the two programs are VASTLY different  - my Sufferfest FTP is 75 watts higher than my Kinetic FTP!   I can't figure out a good way to reconcile them.  I can do a spindown calibration on the Smart Control through the Kinetic app, but there certainly doesn't seem to be a way to do that on Sufferfest.

    I'll keep an eye out for the power matching.

  • Hi Lea,


    Are you using Virtual Watts in The Sufferfest app possibly?  If so that'd be the difference.  If you are connecting the Smart Control to the app, we should be reading power right from that.  

  • Those of us who did ToS following the training plan will take FF test this weekend.
    I hate FF so much, I wished power match was ready by then, so I don't have to do it again soon (my numbers will change with my 4iiii power meter)

  • I also have a Kinetic Smart Trainer but I don't use the Kinetic App.  I am seeing huge power differences between the Sufferfest App reading the Smart Trainer power vs what my head unit says my Stages cranks are reading.  When starting the app, I have had to generate 700W+ to get rolling to a decent cadence yet the Sufferfest App says < 200W.  There seems to be a lag of over 2 seconds on the App vs the Stages.

  • Absence of Power Match feature is making me reconsider SufferFest.  If not available by April I'm heading to Zwift world.  Not well structured workouts but consistency with outdoor riding... Very important to those of us in the Northern Hemisphere.

  • Strange reading the most recent comments...power match is now available on the most recent app...i've been using it for a a few weeks or so now and it works great! matching my Favero Assioma PM pedals through the SUF app to control my Tacx Flux. There's a bit of a lag that sometimes happens on short intervals under 20s but other than that it works well in ERG mode.

    Michael, have you updated to the latest App version?

  • Thanks for the response Marco.  I believe I do have the most recent App (v. 6.0.4).  Is there a secret to making it all work together?  Is there a setting within my Wahoo app I have to change (ie...control with Ant+ Power meter - currently turned on)?

    Please advise...

  • Hey Michael it all happens in the Suf App. As long as you have your power meter on, when you start the SUF app, and start a workout, you open the settings menu and start connecting devices...seems to explain it all here: https://support.thesufferfest.com/hc/en-us/articles/360000578816-Device-Connections

    FYI, I run the SUF app on my desktop. So to get the power meter readings to the desktop (my Assioma's are also ant+) I use a Tacx ant+ antenna (you can use an ant+ dongle but I get better reception closer to my Flux trainer if I put the Tacx antenna close to it I think). So once you can get the signal to the SUF app, it just detects that another power meter is available and gives you the option to link to it as you will see inthe page above.

    Does that make sense?

  • Hi

    I did that.
    The suf app (desktop PC) is configured to use my 4iiii crank power sensor as the power meter, and my smart trainer as ERG device.
    All this does (or what I understand it does) is control the trainer to maintain the target power using the trainer's internal power, while displaying the 4iiii power readings. It's also the 4iiii readings that are exported afterwards in Strava.
    But since my trainer and my power meter have different readings, my power readings are constantly different from the target power.

  • Ah, I see...what you have in fact is power matching!

    Now the issue with the readings "not matching" is actually a different problem I believe. It also happens on my smart trainer as the smart trainer has a range of power it can handle for any given gearing you have set. For magnetic driven trainers such as the Tacx Neo, I don't think it's a problem as you can keep it in one gear...but for belt-driven trainers, like my Flux, each gear setting actually has a power range it can handle based on a cadence range. Here is an example of power range for the 39-19 gear setting on the Tacx Flux: https://tacx.com/erg-training-flux/

    But I am assuming you have a Wahoo Kickr trainer which is magnetic driven like the Neo?

    I've seen comments on the internet such as on the Sufferfest FB site that the Kickr seems to have a lag during ERG mode power matching...more than maybe other trainers. Even those using Trainerroad and Kickr report this: https://forum.trainerroad.com/t/powermatch-experiences/1072/15


    So this could have something to do with the Kickr firmware which has nothing to do with the SUF App...like I said, my Tacx Flux power matches quite well as long as i'm in the right gearing. Another option is to turn off ERG and use Level Mode (which unfortunately is not as nice as using ERG and doing less gear changing.)

  • Please see below I received directly from Sufferfest support: in short, power matching is not implemented. The trainer is still controlled by the trainers power reading. By selecting the power meter it simply displays the power meters reading, it is not used to control the trainer regardless of the brand of smart trainer you’re using. See below:

    Rebecca (The Sufferfest)
    Mar 14, 13:52 CDT

    Hi Brian,

    Thanks for contacting us, I'm sorry for the confusion. We don't have power matching yet but we are moving in that direction. The lightning bolt with the circle is what you will use to have the app control the trainer (you'll still need to select ERG mode from the drop-down menu). The lightning bolt only button will determine which power source is actually displayed as you ride. Even if you pick the power meter, the app will still be using the power from the smart trainer to control the resistance, it will just display the power meter readings instead.

    I hope that wasn't even more confusing, please let me know if you have any other questions!
    Rebecca Bell, KoS
    Minion at Sufferlandrian Services

    One App. Everything You Need to #BeatYourBest

    Try The Sufferfest FREE for 7 Days: https://thesufferfest.com

    Stronger | Faster | Tougher

    Brian Fry
    Mar 14, 06:44 CDT


    With the new app, under the device settings if using both a power meter and a smart trainer, there is the option to have power come from the power meter rather than the smart trainer, correct? Does this mean, as it implies, that power matching is now implemented and just hasn’t been communicated clearly enough to the community as I still see many comments regarding the lack of power matching. If not, then what does it mean when selecting the power icon for the power meter in lieu of the smart trainer?


  • Ah! My bad...thanks for looking into this in more depth Brian! I mistakenly assumed then that those two symbols were allowing power matching and I thought the trainer was adjusting to my power meter values. Good to finally get confirmation...sorry for taking you down that rabbit hole as I got confused myself.

    Sufferfest is promising the power matching early 2019 so I hope they come through with that! I would prefer that my outdoor and indoor rides will have a consistent measure as like you I live in the northern hemisphere.


  • So grateful to have affirmation that I'm not a dullard. I do appreciate the effort and attention Marco, Brian... et al.

    Zwift works, It looks like Suffer Fest Cousin Trainer Road has Power Match feature (though I have not tried it).

    To SF developers...You have such a user friendly, thoughtfully developed platform that organically guide users to full implementation of Power Data.  I would hope that you place this functionality at the top of your priority list.  I purchased my power meter because of my experience on your platform, and look forward to taking it outside with me in the spring.





  • Exactly as I thought. This confirms what I experienced.
    Marco, maybe toning down the strong affirmations would have been a better approach if you weren't absolutely sure about something. That's how false information gets spread around. It's ok to be unsure about something.

  • Come on Ghyslain,

    Have you ever made a mistake?  Marco misunderstood the question and earnestly attempted to assist.

  • Yes, I made many mistakes, many times ! And I understand why there was confusion.

    My point is only about the choice of words. That's why I said : it's ok to be unsure.

    The arguments were strong and presented as if those were undisputable facts.

    I'm sorry if that sounded rude. I do have a scientific background so maybe it's a professional distorsion.

    Seeing how quickly the false information can spread, I just hoped that people would care more to present personal perceptions or hypothesis as what they are, and not as factual claims.

    If it wasn't for Brian, who did check with suff support, we would be a big bunch of people trying to figure out what's wrong in our system configuration for power match not to work, because it was claimed as facts.

  • I understand what you are saying Ghyslain.  I too have been accused of delivering a message without the requisite nod to empathy.  Thank you for your patience with my seemingly brusque remark.

    Though the original question is apparently resolved, the problem persists.  A problem that has been resolved by more than one aggressive competitor.  I very much appreciate Sufferfest and have subscribed to the platform since 2012.  But now that your platform has demonstrated the value of a power meter, I purchased a power meter.  If I can't use it indoors with Sufferfest, I will have no choice than to jump ship.


    Please PRIORITIZE this!!



  • We agree on that !! :-)

    Yes, we need that feature. Badly.

  • Im happy with the progress since i canceled my subscription 6 mths ago. The entire apps is so clean and now at least can connect the power meter. The trick is to ensure that the smart trainer is calibrated properly to give the right resistance to hit target power

  • Hi everyone,


    I have managed to get this to work on my Wahoo Kickr. As someone has said above, you need to go into the newly updated Wahoo Fitness Android (or iOS) app....go into sensor settings, add your kickr and power meter as individual sensors. Then in the Kickr settings tell it to control with 3rd party power meter.

    Then, in the Sufferfest app, tell it to use ERG mode (of course) and also to do the power control AND the power readings FROM THE KICKR. You use the cadence from your power meter. If you have your head unit (Garmin, for example) to take power readings from your power meter, you'll find that the power readings will tally up with those displayed on the app.

    As someone else stated, I found the kickr added more resistance as the unit got warmer and warmer, making workouts too easy to start with, then too hard by the end (eg 100% FTP from my power meter may have been 95% FTP at the start, but as much as 105% by the end)....now though....it's always within 1% or so.

    I asked Wahoo about this and this update to the Wahoo fitness app (Android) was only released a few days ago, I have only tried it once but it worked absolutely fine and made me very happy, since I no longer need to tweak the intensity several times during a session.

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