Legburn Open the app

Strike hard.

Indoor cycling that stays on your computer.

Legburn runs your smart trainer from a browser tab. It holds the power you set or rides the grade you pick, shows live power, cadence and heart rate, and keeps every second of the ride on your own device.

Open the app Free, and no account needed.
  • A hobby project in early development, so expect rough edges.
  • Runs in Chrome or Edge on a desktop.
The Ladder ride screen: power in the middle, the target you control on the ladder.

What it does today

ERG · SIM

Two ways to ride

ERG holds the power you set, whatever your cadence, and eases off if you stop pedalling. SIM turns a road grade into resistance, so a 6 % climb feels like one.

W · rpm · bpm

The Ladder screen

Power big in the middle, your target on a ladder of rungs, and zone colours once you set your FTP. It reads from a metre or three away on a laptop, tablet or phone.

1 s

Every second, saved on your device

The ride is written to your browser's own storage once a second. Reload the page mid-ride and you can carry on where you stopped. Nothing is uploaded, and you don't need an account.

3D

3D sim mode

Swap the numbers for a rider on a road in the middle of a ride, and swap back. It's the same ride either way.

↻

Devices that come back

Legburn remembers your trainer, strap and controller. After a reload, one key reconnects them in order, and the buttons on a supported handlebar controller start, pause and shift.

.FIT

Rides, charted and exported

Each ride opens to a summary: power, heart rate and cadence on one chart and a minute-by-minute table. Export it as a .FIT file for whichever training log you use.

On its way

The cloud and group rides are built and come to the app soon. Then it's workouts.

Built

An optional cloud

Sign in with an email link or Google to keep your rides on every device. It stays off unless you turn it on, and the ride never waits for the network.

Built

Group rides

Share a room code and see everyone's live power, cadence, heart rate and distance, with a shared countdown to start.

Next

Structured workouts

Intervals with targets, so the trainer follows the plan and you follow the ladder.

Later

Routes, virtual shifting and a coach

Real climbs with their gradients, gears instead of watts, and an AI coach to tell you how hard to go.

What you need

Chrome or Edge on a desktop or laptop
Legburn talks to your devices over Web Bluetooth, which Safari and Firefox don't have.
A smart trainer that speaks Bluetooth FTMS
FTMS is the standard Bluetooth protocol for fitness machines, and most recent smart trainers support it.
A Bluetooth heart-rate strap, if you like
Optional. Everything else works without one.

Where it's at

Legburn is a hobby project in early development. You can try it at app.legburn.com: ERG and SIM, the Ladder screen, recording, .FIT export and 3D sim mode work today. The optional cloud and group rides are built and come next, then structured workouts.

There's no release date and no mailing list.