ERG Mode vs Simulation Mode: Which One to Use on Your Smart Trainer
Use ERG mode when the session is about exact power targets (intervals, sweet spot, recovery), because the trainer holds the watts whatever your gear or cadence. Use simulation mode when the session is about a road: the app sends the gradient, the trainer brakes harder on climbs and you manage the effort with your gears. In Cycloscape a free ride is always simulation; a structured workout lets you pick ERG or Ride (simulation, with the targets as guidance) and switch mid-session.
How ERG works
In ERG the app sends a target power and the trainer adjusts its brake to hold it. Pedal slower and it brakes harder; pedal faster and it eases off, so the watts stay put. You don't need to shift: pick an easy gear and keep it there.
That's also its trap. Power is torque times cadence, so if your cadence sags late in a hard interval, the trainer raises the torque to keep the watts, the pedals get heavier, your cadence drops further, and you grind to a halt. Riders call it the ERG death spiral. The way out is to stop fighting it: pause the workout or soft-pedal in the easy gear, let the flywheel spin up, and restart the interval with your cadence up.
How simulation works
In simulation the app sends the road: the gradient, plus rolling and air resistance. The trainer turns that into braking for your speed, so a climb gets heavier and a descent eases off, and you shift exactly as you would outside. Your speed comes from your watts, your weight and the gradient.
In Cycloscape, Trainer difficulty decides how much of each climb your trainer reproduces, from 0 % (climbs as light as the flat, the default) to 100 % (the real gradient). Your speed and the route's stats always use the real gradient whatever you choose.
Which mode for which session
The mode is a tool for the session's purpose, not a level of seriousness. A hilly road in ERG and a set of intervals in simulation are both possible; they just answer different questions.
| Session | Mode | Why |
|---|---|---|
| Intervals, sweet spot, threshold | ERG | Every interval lands on its target, no pacing guesswork |
| Recovery spin | ERG | The trainer stops you drifting above the target |
| Exploring a route or a climb | Simulation | You feel the road and pace it yourself |
| Rehearsing an event's pacing | Simulation | Pacing the terrain is the skill you're practising |
| A workout on a hilly route | Either | ERG for the numbers, Ride mode to feel the terrain |
What happens when you switch in Cycloscape
Two sources writing to one brake would fight, so Cycloscape gives the trainer to one boss at a time. With ERG on, the workout's target goes to the trainer and the terrain's gradient is deliberately dropped: the hill still shows on screen, but it won't change the resistance, and the HUD reads ERG followed by the target wattage. Turn ERG off and the last gradient is sent straight away, so the trainer doesn't sit in the wrong mode.
Targets are percentages of your FTP, fixed when the workout starts, and the panel lets you nudge the whole workout's intensity in 5 % steps. If your trainer can't hold a target power over its current connection, ERG is greyed out and the workout runs in Ride mode. If you also pair a separate power meter, Cycloscape steers the ERG target so that your power meter, not the trainer's own estimate, reads the target.
Frequently asked
Why does the hill look steep while the resistance stays steady?
Because ERG is on. The trainer is holding a power target and the terrain is ignored by design. Turn ERG off to let the gradient set the resistance.
Should I change gear in ERG mode?
As little as possible. Pick an easy gear before the interval and keep it. Shifting makes the trainer re-adjust, and a big gear at low cadence is how the death spiral starts.
Can I do a structured workout without a smart trainer?
Yes, in Ride mode. Without a controllable trainer the targets guide you and you hold them with your gears and legs.
Are ERG workouts free in Cycloscape?
Free rides with a smart trainer in simulation mode are free and unlimited. Structured workouts with ERG control, the workout editor and file import are part of Cycloscape Pro.