I can't take it anymore...back to my KK Road Machine

@craigmanning I think you misunderstand that ERG is not supposed to be a reproduction of road riding. It is a very specific set of programming that aims to hold a set power target.

The requirement is that the rider hold a generally steady input cadence so the controlling app and trainer will work together to achieve a power close to the target.

Hey in this is the fact that it requires steady input and no attempt to chase the power target. Doing so corrupts the process and leads to issue like you described.

You found have used the Snap and set it to Resistance or Standard mode. In those, the trainer acts more like your simple Kinetic Road Machine. If you push harder, the power will increase. Again, this is all about the modes and using that’s intended and ad you prefer.

With your focus on hitting +/-1w, it’s a hard goal, especially for a mid level trainer like the Snap. Other trainers may perform better, but the ERG mode is still something that may end with more variation than you prefer.

Based on all that, it seems you are best served with a standard trainer that you can control directly.


Isn’t trying to hold a power target the entire reason we are doing intervals? To hold X number of watts for X number of minutes, so that we can become stronger? If I hold steady at 95 RPM, my HR is staying the same or climbing and I am exerting a fairly even effort (for a human being) and the power is slowly dropping, I increase my rpm and effort on the pedals but the power doesn’t increase because the program detects faster cadence and actually reduces the resistance. Its kinda the opposite of the death spiral. Even in standard in resistance mode, the magnetic feel of the Snap was not good.

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I like my Core so far, and am enjoying the relentless task master that erg mode is. The feel is smooth and it’s WAY quieter than my Fluid2. That said, I’m keeping the Fluid2 for race warmups and as a backup as well as for a maintenance stand. It started leaking fluid, so it’s on its last legs and is done as a daily trainer, but it’s still going to stay right here and get some use. But even not having explored the full use of the Kickr (Zwift, resistance mode, trainer power not using powermatch), the Core is a better machine by a long shot IMO.

Right, and if you see the power drop a bit (which is common in any mode) you need to resist the urge to “fix” it yourself. You need to maintain cadence and let the app/trainer combo do the work.

Attempting to increase power by accelerating just leads to the problem you describe of runaway cadence.

Yes, the goal of our work is to spend time at specific power levels for certain time. But in either case of manual or ERG controlled, there is variability. The complexity of the ERG process grows with the inclusion of PowerMatch. It’s another variable and time delay in the process.

Nothing is perfect. So it’s about understanding the pros and cons and choosing what is best. I still have and use my KKRM on occasion, even with my extensive use of smart trainers. I like them all for different reasons.


Just as some people cover up the power output field on a ramp test I might try covering it up on intervals to see what happens. I’ve also found not looking at the screen as the interval starts seems to help me with the transition.

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I think this is a little bit of your struggle. 1 watt. I used to be coached by Trevor Connor, and he had a great saying that I’ve tried to apply always:

“Don’t let perfect get in the way of good enough.”

Like @mcneese.chad has said as well, I would spin at 95rpm (or whatever cadence you feel comfortable) and let the machine do its thing. Based on how you’ve described your issue, my personal opinion is that it’s a psychological mindset that the Snap isn’t getting you the training you want. Or, you can go back to the KK and feel better about your training…but you posted here so i am assuming you’re looking for others to agree/dispute your experience as a means of assessing if you’re “doing the right thing” by getting back on the KK.

At the end of the day, you’re still training. Keep at it.

I’ve actually found the opposite. Since going smart and having erg mode, I can do all the cadence drills in TR. I’m more comfortably able to react, and spin up to a higher cadence to move or close a gap. Well that’s my n=1 study anyway.

When I was on a dumb trainer, those cadence drills always seemed to be a compromise between hitting the cadence or hitting the power target (either over or under).


I think OP most likely isn’t used to the erg mode, we must have heard numerous people reporting the odd feel of it. I think it’s just in mind - rather than a person controlling the workout, the trainer is doing that and executing the workout as designed, no less, no more. One is only free to chose their cadence.

In photography analogy, if you shoot in Aperture mode, whatever aperture you choose, camera will attempt to adjust the Shutter speed automatically. Erg mode is essentially same in trainer world.

Im on my 5th trainer in 12 months. all the following where used with a power meter

Elite dumb trainer (max 250watts, couldnt even complete an FTP test)
Tack Flow (hated the feel and too slow to adjust)
2017 Wahoo Kickr Snap (felt great and exactly how i wanted it to feel for the most part)
Tacx Satori (actually felt alright but too little inertia, felt very sloppy/ choppy on longer intervals)

Finally on to a KK Road Machine and absolutely love the thing, the inertia is perfect for me, I’m using the dumb version with a power meter and can hold power quite easily, no plans to go smart again just yet.


Not looking for approval…more just seeing if others viewed ERG the same way. Im back on the kinetic for the foreseeable future…it just feels better to me.

It just seems that the trainer companies could just tweak their programs a bit and make these things so much better.

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That would be great, but it’s not that simple.

The two components (trainer and app) both have inherent limitations. The most significant is time.

Trainers need time to move from one resistance level to another. The time varies based on the total power delta and the basic design of the adjustment method. Each trainer model and brand varies a bit with some being faster than others. Couple that with the variability that comes from the drive ratio on the bike and you get some hurdles.

Then on the app, you have the Loop that reads the current power, looks for changes up or down, sends the adjustment commands to the trainer, and reevaluated the power… rinse and repeat.

If we add PowerMatch into the loop, that increases the time difficulties.

Like too many things in life, the reality is more complicated than the theory. I do think we will see improvements in apps and trainers, but it will take some tech changes to start. Then I think the app and trainer makers need to work together to blend both for the most responsive combo possible.

It all works right now, but it’s not to the level of control and perfection that many would like to see. I love ERG, but accept the limitations in light of what I gain compared to manual control. It’s about compromise right now, until they improve the experience even more.


The ANT+ FE-C spec allows the app to send the trainer a target power, and lets the trainer do “the loop”.

This sis, erg-mode training does take a while to get used to, it feels counter-intuitive (certainly no on-road situation matches this lower cadence = higher load setup). But it’s really good to develop cadence+power ability. Just forget about the power number, and drive the cadence.

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Completely agree with your post and all the supporting details, however…

I think the time that most of these things take is not the limiting factor. I think the problem will always be that when people try to chase the power the applications and hardware will struggle.

There will never be real time feedback - not because it won’t be achievable (or at least, near enough to real time that our brains and bodies can’t tell the difference) but because it isn’t desirable. Instantaneous adjustments in resistance would be incredibly problematic for even the smoothest of pedal strokes so there will always be some power fluctuation - you don’t want the trainer adjusting that quickly

It really is a mental training thing - you must learn, and be comfortable with, the concept of not chasing the power through cadence

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I agree with the snap being flawed. It was maddening trying to use “my” cadence and not the cadence it wanted. If I needed to try to spin my way out of an interval or, stated another way, stay on top of a gear, the snap would increase the resistance, even when above the target power and drag my cadence lower. I detest that trainer and their “support” if that’s what they want to call it.

My solution was to send it back and try another and it was the same issue. I just think there is an issue that is best corrected by moving to another brand. No issues like that with my new unit. I set the cadence and the unit adjusts the power to compensate for that cadence. I can do 60 RPM or 120, at 300 watts, and everyone is happy.

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I’m sure you know this but the fluid 2 has a lifetime warranty. Simply return it to any dealer and they will have it replaced for free. I’ve done it once and was very impressed.

I’m confused by this - were you really not seeing this behavior with the Kickr Snap? By this I mean if you pedaled at a consistent cadence (regardless of what that cadence was) it wouldn’t get you in the 295-305 watt range? Was it that it wasn’t exactly 300, or was it that it wasn’t even close?

Was it worse when you maintained 60 RPM or when you maintained 120 RPM?

Yup. I try to get people to focus on their cadence, and holding it steady (at whatever rpm they want) as opposed to watching the power. It’s really best to ignore power all together and let the app and trainer work it out. There will always be some up and down and that is fine.

I expect that most people get similar variation in manually controlled workouts as well. I know it’s possible to get a more narrow range with a standard trainer and attentive use from the rider. That is fine if that is important, but I’d wager that many people end up with a similar variability (power max/min range within the interval, not just the final average) over time in all of their workouts, just like we see in a typical ERG workout.

@rocourteau The info about the ANT+ FE-C is interesting. It may well end up with better results if you can “tighten” the circle in the loop a bit. Faster reaction to a point is beneficial. I also agree that instant adjustment may seem ideal, but would likely lead to it’s own set of issues. Again, the theoretical perfect often is not what we really need, considering the inherent variability that we introduce from our own involvement.

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Right, and if you see the power drop a bit (which is common in any mode) you need to resist the urge to “fix” it yourself. You need to maintain cadence and let the app/trainer combo do the work.

I just want to echo this. Especially with Powermatch.

  • Keep your cadence consistent.
  • Don’t chase the number.
  • Don’t fret the 1-2watt under.

It works out in the end.


Note that the Bluetooth FTMS profile also allows for a power setting to be sent to the trainer. I’m not sure if this is how apps and trainer manufacturers implement erg mode, but the option exists in the specification.

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