Disadvantage of ERG mode?

I apologise if something similar has been posted before.

I ride a wheel on standard tacx trainer and, although I’ve never ridden a smart trainer, I can certainly see the benefit of a smart trainer and erg mode. I do plan to get a smart trainer in the future.

I do wonder though if you lose some benefits by riding in erg mode.

Firstly, when completing intervals with a standard trainer with a power meter there’s often a compromise to be had in terms of cadence to hit a certain power. For example having to spin a few rpm above or below my preferred. This can be a bit frustrating but I wonder if it helps to improve my range of comfortable cadences?

Secondly, to keep at target power requires producing the power but also a degree of concentration and control to keep the power up and now go too much over. It strikes me that this is more similar to riding outside and aiming for a target power.

I’m interested to know what people with smart trainers think.


  • Or you could argue that you aren’t able to hit the middle points within a range and that is a problem in itself.
    • Ex: If you are given the restriction to ride at 90 rpm or 100 rpm, are you missing out on the chance ride at 95 rpm?
  • My point is that you are actual more restricted via Resistance vs more options in ERG. It is purely up to the rider to choose their cadence in ERG. As such, we can be as narrow or wide as we want.
  • It is a common misconception among those that have not used ERG, that it removes all thought and processing from the rider. That is far from the truth.

  • Yes, when riding on ERG, you can pay less attention to the power target specifically and that is different from Resistance mode to a point.

  • But, if you totally ignore your power effort (specifically via cadence, to be covered more later) you may find your cadence drifting too high or too low for the desired training.

    • The most common problem from cadence drift (whether due to lack of attention or fatigue) is a slower cadence that leads to increase in resistance… and that can cascade into the spiral of death an eventual clinch.
  • The point? Unless you are tooling around in Z2 rides, you need to pay attention to cadence in ERG with the same level of focus that people do for power targets by people using Resistance mode.

    • That focus on cadence and keeping it steady will result in more steady load applied to the rider, and less variation from the trainer and controlling app.

We covered this in great depth in the old thread and debunk a number of the myths and misconception around ERG mode.

These are also good resources that explain more about how ERG actually works:

Feel free to ask further questions if these answers don’t make sense.


Thanks for the reply.

I’ll take a look at the other thread - it looks like it answers my questions and more.

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I would say that while I get what you’re saying about being able to ride at your preferred cadence in ERG vs having a cadence outside of your comfortable range forced on you in resistance mode (and the possible benefits of this being forced on you).
My experience (dumb trainer & virtual power) vs smart trainer is this:
When I was on the dumb trainer, there were certain workouts that I found it nearly impossible to do the workout as designed as far as cadence recommendations went.
A good example is Tunnabora where they ask you to slightly increase your cadence as the power requirement decreases. There are lots of examples where they want you to go just at the top of your preferred range (3-5 rpm above ideal is often recommended) but also give instruction to not let heart rate climb more than a few BPM. These types of subtle cadence changes that allow you to slowly grow your comfortable range over time are simply not possible while holding a power target with a simple resistance mode trainer.
On the other hand some workouts go really well with resistance mode. The beauty of a smart trainer is that you have the option of using it in either mode. Options are good…


i got a smart trainer last year after many years of indoor training. I have a love.hate relationship with erg mode but however you end up feeling or whatever you hear, don’t let it put you off getting a smart trainer. Smart trainers are great.

My issues stemmed primarily from my unwillingness to change workout intensity or, for some workouts, to man up and turn erg mode off. There are some workouts, and just some days, where having the trainer set your power sucks. For other workouts, and on other days, erg mode is great.

All the issues you raise come up sometimes. Just don’t fall into the trap of thinking its got to be all erg at 100% intensity all the time. Take control of your trainer and do what you like.


Whether it’s the fact that having bought a smart trainer to use Erg mide and am therefore spending longer on it, or it’s erg mode itself, I’ve found my pedalling has become a lot smoother. This has transferred to outside rides. I used to be a real stomper but only the other week someone complimented me on how smoothly I pedalled.