ERG mode increases RPE for Z2 workouts

When I was doing lots of intervals around 100% FTP, ERG mode inside was fine for me and from a psychological standpoint it felt good doing these indoors.

Recently I switched to a more polarized training scheme and most of the time I am going at a far lower intensity. This becomes very boring done inside and that then very quickly starts to increase the RPE and the workout feels much harder than it actually is. What I discovered is that taking the trainer out of ERG mode and using the mode that simulates riding outside, where resistance is dependent on speed, acceleration and slope, makes the workout much more enjoyable and brings back down the RPE to where it should be.

Was wondering if others have similar experiences?

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If I’m doing a Z2 ride on Zwift, it’s a lot more engaging (and so RPE is lower) to do it as a free ride and modulate the power in response to the terrain.

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Feeling exactly the same. I assume part of it is that one is sitting very static on the bike and also having the constant pressure on the pedals, rather than having micro breaks during the workout.

If I am carrying some fatigue into a workout I also have a tendency to ride with a very low cadence in ERG mode workouts.

How does your gearing differ between your trainer mode uses?

It’s possible that you may be experiencing a different flywheel feel if you are using something like a low gear in ERG vs higher gear in RES or STD.

Additionally, are you using the same cadence in both situations?


I think ERG mode should be adjustable for varying cadences. The spiral of death seems to start around 82 rpm on my H3, get below 82 rpm even at around 120 watts (rest intervals) and it starts to feel like you are pedaling through mud. There should be a way to dial that down to say 75 rpm, or even lower depending on individual preference and one’s natural cadence.

It varies between users at the vary least. I’ve done extended low cadence work (55-65rpm) in ERG on H2, Kickr V3/6, Neo2. All done in 34t x 17t at Z2 for minutes to hours at a time.

I’ve done over 3 hours continuous at these cadences without hitting the death spiral. The power level is low but you do need to maintain good force early and through the pedal stroke.

That “mud” feeling makes sense to me and as is not unlike the older trainers I’ve used with minimal flywheels (cheaper fluid in particular). They didn’t “help” maintain the pedal inertia the way that other nicer dumb trainers did (Kinetic Road Machine).

Main point though is that holding low cadence in ERG is possible. The aforementioned rides I’ve done are usually with me watching TV and movies, so it’s the pedaling happens without much thought or focus if you get used to it.

I’m actually the opposite. I find turning off Erg for Z2 rides increases my RPE because I have to constantly pay attention to what I’m doing so that I don’t float up or down. With Erg on, I just turn on the TV and check the time once in a while.

Instinctively, I would assume that turning Erg off for Z2 should lower RPE, but in reality, that’s not what I experience (although that might change if I was paying attention to Zwift instead of whatever show I’m watching)


I like to do workouts some times on a virtual course, that variance can make it more interesting indeed.

Welcome to the club!

That mud feeling has always been why I dont like magnetic trainers. When I had a Snap it was horrible but the H3 is so much better but I still feel it. Too bad they cant come up with a smart fluid trainer…some type of fluid that thickens or thins based on electrical current or something.

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Zwift also has the additional entertainment from the riders around you.

It feels the same way even if I am not taking breaks in free ride mode. I guess free ERG takes away some thinking and engagement and that could be causing that effect.

I am using the TrueBike. So no flywheel. But I think the flywheel effect is about comparable because the speed that the bike indicates is about the same in both modes. When in ERG the speed is totally dependent on the virtual gear that I choose. But if I choose a slow gear with low speed, it will feel like bike has less momentum through the dead fase just like on a regular smart trainer.

Yea that would be very trainer dependent. I am not experiencing that myself. On the truebike the ERG mode is adjustable as you can choose how fast it adjust to the cadence.

How long are those Z2 rides?
It beats me how people can pay constant attention to their power and adjust gearing.
I am on mechanical red22 so maybe it is that. It sounds like a platoon setting up their rifles.

Indoors is 1.5 hours normally. But now there is ice outside on the roads, I have to do the 3-3.5 hour weekend rides also inside.

I can do it by feel mostly, there is a fairly wide range of about 20W and only need to look at the screen sometimes.

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I find a long turobore trainer ride boring but a lot of folk are using ERG and don’t need to shift much, if at all.

Since started to use level mode in wahoo I never touch erg. It’s not any purists statement but in my case I am more engaged into workouts, I really like to change level mode and recruit muscle just a little bit differnetly and not to mention dialing my RPE way better and learing how power should feel and not being restricted by some arbitrary percentages. Not to mention riding outside feels better after using level than after erg.


yes its pretty easy to learn how it feels. As with anything, practice is key. You naturally get that riding outside. And then sooner or later you are riding by feel with very few glances at the bike computer.


I feel the same, but I’m not a lover of erg mode generally (just a personal preference thing, but I also have a tendency to let my cadence drop over the course of a longer ride, so resistance mode is a good way to both keep an eye on that and keep my hamster brain interested.)

In any case, I think 3.5 hours steady z2 indoors is for most going to be mentally challenging enough that i’d be going out of my way to make it as engaging/palatable as possible-don’t think there’s much to be gained by holding yourself to a specific way of doing things anyway.

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I completely agree with this point. During my low-tempo / Z2 rides, I prefer to use the resistance mode because I find that it helps me maintain a better RPE and keeps me more engaged. For rides longer than two hours, I usually switch to using Zwift because it’s more enjoyable to ride with a virtual group and the time seems to pass more quickly. I have no problem riding indoors for four hours, but it can be a bit monotonous without some social interaction.