Updated 2026-10-23 · Setting up and getting started
Short answer
In ERG mode the trainer adjusts its own resistance to hold a target power, whatever gear you are in. Slow down and it gets harder; speed up and it eases. It is excellent for structured intervals because you cannot drift off target, and poor for sprints and anything needing fast changes.
How it actually feels
Normally, power is up to you: harder gear or faster legs means more watts. In ERG, the software names a number and the trainer defends it.
In ERG mode the trainer adjusts resistance moment by moment to hold the target. Your cadence can wander all it likes and the power does not move — which is the point, and also why a dropping cadence can run away with you.
Try to ease off and the resistance increases to keep you at the number. Push harder and it backs off. The practical result is that your cadence becomes the thing you control, and the power stays put.
Most people find it takes a session or two to get used to, because the usual relationship between effort and gear has been removed.
When ERG is the right choice
Structured intervals. You cannot accidentally do 240 when the plan said 220, and you cannot fade in the last minute. The session gets done as written.
Easy and endurance rides. Very good at stopping you riding your easy days too hard, which is the most common training mistake there is.
Sweet spot and threshold work. Long steady efforts where drifting is the main risk. See sweet spot training indoors.
When you are tired. It removes the decision-making.
When to turn it off
Sprints and very short, very hard efforts. There is a lag of a second or two while the trainer catches up, which ruins anything under about 30 seconds.
Anything with fast changes between very different powers.
Standing efforts, which tend to spike your power and fight the trainer.
When you want to practise pacing, because ERG does the pacing for you and that is a skill you need outdoors.
When you simply want to ride. Free riding in resistance mode is more like the road.
The spiral of death, and how to avoid it
This is the one failure everybody meets eventually.
In ERG, if your cadence drops, the trainer increases resistance to hold the power. Harder resistance makes your cadence drop further. The trainer responds by making it harder again. Within a few seconds you are grinding to a halt at an impossible resistance and have to stop.
Avoiding it:
Use a low gear. Something like the small chainring and the middle of the cassette. In ERG your gear does not set your power, so a low gear costs you nothing and gives the trainer a much finer range to work with.
Keep your cadence up and do not let it sag at the end of a hard interval.
If you feel it starting, stop pedalling for a moment and let the trainer reset, rather than fighting it.
Be honest about the target. If you cannot hold the number, ERG will not negotiate. Lower it.
Common questions
Does ERG mode make training easier?
It makes it easier to execute and often harder to survive, because it will not let you drift. Many people find a session in ERG tougher than the same session self-paced.
What gear should I be in for ERG mode?
A low one. Small chainring, middle of the cassette is a good default. It does not affect your power and it gives the trainer more room to adjust.
Why does my power overshoot at the start of an interval?
Most trainers ramp to the new target over a second or two, and if you push hard into that change you can spike above it. Let your legs follow the trainer rather than anticipating.
Can a dumb trainer do ERG?
No. ERG needs the software to control the resistance, which requires a controllable smart trainer.
Still bored of the turbo?
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It is in closed testing at the moment, so there is nothing to play yet.
But you can put your name down.
