Quick Answer: The original Peloton Bike has no motor, so it can't change its own resistance for ERG or SIM mode the way the Bike+ can. But you can add automatic resistance by pairing a SmartSpin2K — an open-source device that physically turns your resistance knob — with FitSwitch. FitSwitch supplies accurate power and cadence to your training app, while the app sends resistance commands to the SmartSpin2K. The result: true auto-resistance in Rouvy, Zwift, and other apps on a bike that was never designed for it.
Table of Contents
- Why the Original Bike Can't Auto-Adjust Resistance
- What the SmartSpin2K Does
- How FitSwitch and SmartSpin2K Work Together
- Setting It Up with Rouvy
- What to Expect
- FAQ
Why the Original Bike Can't Auto-Adjust Resistance
On the Peloton Bike+, resistance is controlled by a small internal motor. That's what lets FitSwitch deliver ERG mode (hold a constant wattage) and SIM mode (resistance changes with the virtual hill) — the software sends a target and the motor turns the magnets.
The original Peloton Bike has no such motor. Its resistance is set entirely by the manual knob you turn with your hand. There's simply nothing for software to grab onto, which is why apps like Rouvy and Zwift can show you a target wattage on the original Bike but can't change your resistance for you. You have to reach down and turn the knob yourself.
That's the gap the SmartSpin2K fills.
What the SmartSpin2K Does
The SmartSpin2K is a popular open-source DIY device that mounts over your bike's resistance knob and turns it with a small motor. It effectively gives a "dumb" knob-based trainer the auto-resistance ability of a smart trainer. It connects over Bluetooth and presents itself to training apps as a controllable smart trainer (using the standard FTMS protocol), so when an app calls for more resistance, the SmartSpin2K physically turns your Peloton knob to match.
Because it's an open-source community project (not a Peloton or FitSwitch product), you build or buy one separately and mount it on your bike. Once it's on, it pairs with apps just like any smart trainer.
How FitSwitch and SmartSpin2K Work Together
This is the key to a great setup: each device does the job it's best at.
- FitSwitch reads your Peloton's built-in sensors and broadcasts accurate power and cadence (plus heart rate) over Bluetooth and ANT+. This is real measured data straight from the bike — no estimating.
- SmartSpin2K receives resistance commands from your training app and turns the knob to create the right effort.
So in your app, you connect two different signals:
- Power and cadence → FitSwitch. Your wattage and RPM come from the Peloton's own sensors via FitSwitch, which are accurate and consistent with what your Peloton screen shows.
- Resistance/controllable trainer → SmartSpin2K. When the app wants to change difficulty (a climb in Rouvy, an interval target in a workout), it sends that command to the SmartSpin2K, which turns the knob.
You pair to the SmartSpin2K's Bluetooth service for resistance control, rather than the FitSwitch service, when you want the knob to move automatically. FitSwitch handles the data, SmartSpin2K handles the muscle.
Setting It Up with Rouvy
Rouvy is a great example because it uses both your power data and resistance control for realistic route riding. Here's the general flow (exact menu names vary by app version):
Step 1: Make sure FitSwitch is installed and running on your Peloton, and your FitSwitch Bridge app is set up if you're running Rouvy on the Peloton screen itself.
Step 2: Power on and pair your SmartSpin2K over Bluetooth so it's discoverable.
Step 3: In Rouvy's sensor/pairing screen, connect: - Power source: FitSwitch (the Peloton's real power output) - Cadence: FitSwitch - Controllable / Smart Trainer (resistance): SmartSpin2K
Step 4: Start a route. As the terrain changes, Rouvy sends resistance commands to the SmartSpin2K, which turns your knob — you feel the hills automatically while your on-screen power and cadence come from the Peloton.
Step 5: Optionally connect a heart rate monitor through FitSwitch for full metrics.
If you're running Rouvy on a separate phone or tablet instead of the Peloton screen, the pairing is the same — just done on that device.
What to Expect
- Real auto-resistance on a non-motorized bike. Climbs and intervals adjust without you touching the knob — something the original Bike can't do on its own.
- Accurate power. Because FitSwitch reports the Peloton's measured output, your numbers stay consistent with your Peloton history rather than relying on a third-party estimate.
- A DIY project. The SmartSpin2K is a community-built device. Expect to spend some time mounting and calibrating it, and know it's supported by its open-source community, not by Peloton or FitSwitch.
- Bike+ owners don't need it. If you have a Bike+, FitSwitch already does ERG and SIM mode through the built-in motor — no extra hardware required.
For most original-Bike riders who want the full smart-trainer experience, the FitSwitch + SmartSpin2K combination is the most complete option available.
Frequently Asked Questions
Does the original Peloton Bike support ERG mode?
Not on its own — it has no motor to change resistance. FitSwitch enables ERG and SIM mode automatically on the Bike+. On the original Bike, you can add automatic resistance by combining FitSwitch (for power and cadence) with a SmartSpin2K (to turn the knob).
Can I use SmartSpin2K with FitSwitch?
Yes. Use FitSwitch as your power and cadence source, and connect to the SmartSpin2K's Bluetooth service for resistance control in your training app. Each handles a different part of the setup.
Is the SmartSpin2K made by FitSwitch?
No. SmartSpin2K is a separate open-source community project. You build or buy it independently and mount it on your bike. FitSwitch works alongside it but is a separate product.
Why not just use SmartSpin2K alone for power too?
The SmartSpin2K estimates effort from knob position, while FitSwitch reads the Peloton's actual built-in power meter. Using FitSwitch for power and cadence gives you accurate, consistent numbers that match your Peloton screen, while letting the SmartSpin2K focus on resistance.
Do I need this on a Bike+?
No. The Bike+ has motorized resistance, so FitSwitch delivers ERG and SIM mode without any extra hardware. The SmartSpin2K is only useful for the original, knob-based Bike.
Will this work with Zwift and other apps too?
Yes. Any app that supports a controllable smart trainer over FTMS (Zwift, Rouvy, TrainerRoad, and others) can send resistance commands to the SmartSpin2K while taking power and cadence from FitSwitch.
Turn Your Original Bike Into a Smart Trainer
The original Peloton Bike wasn't built for automatic resistance — but with FitSwitch supplying accurate power and cadence and a SmartSpin2K turning the knob, you get the full climb-and-interval experience in Rouvy, Zwift, and beyond.
With FitSwitch, you get: - Accurate power, cadence, and heart rate broadcast over Bluetooth and ANT+ - Compatibility with Rouvy, Zwift, TrainerRoad, and more - A metrics overlay on the Peloton screen - Built-in ERG and SIM mode on the Bike+ — no extra hardware needed
Get FitSwitch — The foundation for a true smart-trainer setup on any Peloton.
Last updated: June 2026