Quick Answer: ERG mode is automatic resistance control that maintains a target power output regardless of your cadence. The Peloton Bike+ has the hardware for ERG mode (motorized resistance), but Peloton doesn't enable it. FitSwitch unlocks ERG mode on your Bike+, enabling structured training with automatic resistance in Zwift, TrainerRoad, Netflix, and any app with the FitSwitch overlay.
Table of Contents
- What is ERG Mode?
- Why Doesn't Peloton Have ERG Mode?
- How FitSwitch Enables ERG Mode
- Using ERG Mode
- ERG Mode Tips and Best Practices
- FAQ
What is ERG Mode?
ERG stands for "ergometer"—a device that measures work output. In cycling, ERG mode means the trainer automatically adjusts resistance to maintain a specific power output.
How ERG Mode Works
- You (or an app) set a target power: 200 watts
- You pedal at your chosen cadence: 90 RPM
- The trainer calculates resistance needed for 200W at 90 RPM
- If you slow to 85 RPM, resistance increases to maintain 200W
- If you speed to 95 RPM, resistance decreases
- Result: constant 200W regardless of cadence
Why ERG Mode Matters
For Structured Training: - Hit exact power targets during intervals - Execute workouts precisely as prescribed - No guessing or constant power watching - Focus on pedaling, not resistance adjustment
For FTP Testing: - Ramp tests execute perfectly - Consistent power for 20-minute tests - Accurate, repeatable results
For Recovery Rides: - Stay in Zone 1 without thinking - No accidentally going too hard - True easy spinning
For Sweet Spot Training: - Maintain exact 88-94% FTP - Perfect for base building - Consistent training stimulus
Why Doesn't Peloton Have ERG Mode?
Your Peloton Bike+ has everything needed for ERG mode: - Motorized resistance knob — Can be controlled programmatically - Accurate power meter — Measures your output - Powerful processor — Can run control algorithms
Peloton uses the motor for "Auto-Follow" during classes—automatically matching instructor callouts. But they chose not to implement ERG mode, likely because:
- Class format — Peloton classes use instructor-led resistance callouts
- Product positioning — They're selling content, not smart trainer features
- Simplicity — ERG adds complexity for casual users
- Differentiation — Keep it distinct from "trainer" products
The hardware is capable. Peloton just doesn't expose the feature.
How FitSwitch Enables ERG Mode
FitSwitch unlocks your Bike+'s ERG capability, making it work like a professional smart trainer.
How It Works
- You set a target power — Either manually or from a training app
- FitSwitch monitors your actual power — Reading from the Peloton's sensors
- Resistance adjusts automatically — If you slow down, resistance increases; speed up, it decreases
- Power stays constant — Regardless of your cadence
The system uses sophisticated control algorithms to maintain smooth, stable power that feels natural—the same technology used in professional smart trainers.
Setting Target Power Manually
For step-by-step instructions with screenshots, see the ERG Mode Instructions.
Quick steps: 1. Open any app with the FitSwitch overlay visible 2. Tap on the power/output reading in the metrics bar at the bottom 3. The control panel opens with +/- buttons 4. Adjust to your desired target wattage 5. Tap the green checkmark to confirm (or red X to disable ERG)
The Bike+ immediately starts maintaining your target power.
ERG via Training Apps
Training apps like Zwift and TrainerRoad can control ERG mode automatically:
- App sends target power — Via FTMS or ANT+ FE-C
- FitSwitch receives the command — And adjusts resistance
- Power data flows back — App sees your actual output
- Loop continues — Real-time control throughout your workout
For apps running on the Peloton tablet, the FitSwitch Bridge app handles communication. For apps on external devices, connect directly via FTMS or FE-C.
Using ERG Mode
ERG mode works with any app that displays the FitSwitch overlay—this includes training apps, streaming apps, and more.
Compatible Apps
ERG mode functions with: - Zwift — Structured workouts and free riding - TrainerRoad — Interval training with ERG control - Rouvy — Video routes with gradient simulation - Netflix, YouTube, Disney+ — Maintain target power while watching - Any app with the FitSwitch overlay — Set your own target
Zwift with ERG Mode
During workouts: 1. Select a structured workout in Zwift 2. Zwift displays target power for each interval 3. FitSwitch adjusts resistance to hit targets 4. You maintain steady cadence 5. The bike handles power control
During free riding (simulation mode): 1. Zwift sends gradient data 2. FitSwitch increases resistance for climbs 3. Decreases for descents 4. You feel the virtual terrain
TrainerRoad with ERG Mode
TrainerRoad is built around ERG mode: 1. Open a workout 2. Intervals display with target power 3. FitSwitch executes each interval precisely 4. Adaptive Training analyzes your performance 5. Future workouts adjust based on execution
Streaming Apps with Manual ERG
While watching Netflix or other content: 1. Open the app with FitSwitch overlay visible 2. Tap the power reading to open ERG controls 3. Set your target wattage (e.g., 175W for Zone 2) 4. Watch your show while maintaining consistent power 5. Perfect for recovery rides or steady-state training
ERG Mode Tips and Best Practices
Cadence in ERG Mode
ERG mode maintains power regardless of cadence, but cadence matters:
Too Low Cadence: - Resistance becomes very high - Can cause "spiral of death" - Muscle fatigue without cardiovascular load
Too High Cadence: - Resistance becomes very low - Less efficient power transfer - Can feel "spun out"
Optimal Range: - Most riders: 85-95 RPM - Find your comfortable cadence - ERG works around your preference
Avoiding the "Spiral of Death"
When you fatigue in ERG mode: 1. Power drops briefly 2. ERG increases resistance to compensate 3. Legs work harder 4. You slow more 5. Resistance increases more 6. Eventually can't continue
Prevention: - Maintain cadence even when tired - Drop cadence deliberately if needed - Practice staying smooth through fatigue
Workout Mode vs Free Ride vs Manual ERG
- Structured Workouts — App sends targets, ERG controls resistance automatically
- Free Ride/Simulation — Gradient affects resistance, power varies with effort
- Manual ERG — You set target power via overlay, bike maintains it
Frequently Asked Questions
Does the original Peloton Bike have ERG mode?
No. The original Bike has a manual resistance knob—no motor. ERG mode requires the Bike+'s motorized system.
How does FitSwitch control the resistance?
FitSwitch communicates with the Bike+'s resistance motor using Peloton's internal protocols. It sends commands that the motor executes, just like Peloton's Auto-Follow feature.
Is ERG mode the same as Auto-Follow?
Similar concept, different implementation: - Auto-Follow — Matches instructor resistance callouts (1-100 scale) - ERG mode — Maintains specific wattage regardless of cadence
ERG is more precise for training purposes.
Do I need the FitSwitch Bridge app?
It depends on where the app is running: - Apps on the Peloton tablet: Yes, Bridge handles the FTMS communication - Apps on external devices: No, connect directly to FitSwitch via FTMS or ANT+ FE-C - Manual ERG control: No, tap the power reading in the overlay to set target directly
How accurate is ERG mode?
FitSwitch's PID control typically maintains target power within 2-5 watts. It's comparable to dedicated smart trainers.
Can I disable ERG mode?
Yes. Tap the power reading in the FitSwitch overlay, then tap the red X to disable ERG mode. In training apps, you can also select "level mode" or similar in the app settings.
Does ERG work in Zwift races?
Races don't use ERG mode—you control your effort. ERG is for structured workouts where you want the bike to hit targets automatically.
What's the difference between ERG and simulation mode?
- ERG mode — Targets specific power, ignores gradient
- Simulation mode — Resistance matches virtual terrain, power varies
Both work with FitSwitch on Bike+.
Can I track ERG workouts on my Apple Watch?
Yes. FitSwitch broadcasts your power, cadence, and heart rate to Apple Watch and Garmin devices.
Unlock Your Bike+'s Hidden Potential
Your Peloton Bike+ has a motorized resistance system capable of professional-level ERG mode. FitSwitch unlocks this capability:
- Full ERG mode for Zwift, TrainerRoad, Rouvy, and more
- Manual target power in any app with the FitSwitch overlay
- Smooth, accurate resistance control
- ANT+ FE-C and FTMS support for external devices
- Smartwatch connectivity (Apple Watch, Garmin)
Train smarter with automatic resistance control.
ERG Mode Instructions — Step-by-step setup guide with screenshots.
Get FitSwitch — ERG mode on your Peloton Bike+.
Last updated: January 2025