On your phone while you ride and in your history: telemetry turn by turn, the road surface metre by metre, several sensors on the same bike and your raw data on DataLab.
Drag to rotate · wheel or pinch to zoom · pause to stop it · elevation ×5
The ride ribbon: a 42 km loop as the sensor records it, with test data. Colour = speed, height = elevation, grain = roughness, veil = wet. With “sensor only” the loop unrolls into a straight band, as it is when your phone stays home.
Speed, surface and impacts at every turn of the wheel, about every two metres, with elevation and temperature: on your phone while you ride.
With your phone in your pocket, the surface metre by metre instead of in 64 stretches, even on long rides.
Your routes coloured by the measured surface, with potholes and cobbles marked on your phone's GPS track.
Every hard hit with time, place and intensity: you know where the wheel took the blow.
Wear estimates for tyres, rims, bearings and fork weighted on the gravel and cobble kilometres you actually rode.
On datalab.crankpal.com, the raw and processed data of every ride recorded by your phone: to look at, download (CSV, JSON, GPX, FIT, .mat) and analyse, in MATLAB Online too.
A summary of surface, impacts and kilometres to show your mechanic at the check-up.
Rear hub, crank, frame and front hub, one for every point: cadence, gears, lean angle, comfort and fork join speed and surface.
Free with the sensor, always: the ride log, the surface of every ride, lifetime odometers and updates.
With CrankPal Pro you can fit several CrankPal Sensors on the same bike, one for every point: rear hub, crank arm, frame, front hub; plus your power meter, if you have one. It's always the same sensor: what changes is where you put it, and what it sees.
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Distance, speed, surface, impacts, elevation and wet. It's everyone's sensor, the base one.
Cadence, pedalling or freewheeling, gear in use: drivetrain wear, sprocket by sprocket. With a bike computer it also works as a cadence sensor.
Lean angle, jumps, instant braking, standing or seated and what reaches the rider: comfort, and an estimate of when to have the rear suspension checked.
No chain up front: a cleaner surface reading and a front/rear comparison, skidding under braking, a tyre losing air, wear tracked separately front and rear.
With your Bluetooth power meter: measured watts, training load, where the watts go and drivetrain wear weighted by the real force.
Even without CrankPal Pro, the rear hub alone gives you, once per ride, the ride log with surface and wet stretches, the wear estimate and the report for your workshop, and lifetime odometers. With Pro the same data arrives metre by metre and live, and the other sensors join in.
✓ available · ↑ improves · — not derivable · “as on the left”: same as the previous column
Scroll the table sideways to compare the sensors and power.
| Data | 1 · hubthe base sensor | 2 · + crankwith CrankPal Pro | 3 · + framewith CrankPal Pro | 4 · + front hubwith CrankPal Pro | + powerwith your Bluetooth power meter |
|---|---|---|---|---|---|
| From the rear hub | |||||
| Distance and speed | ✓From wheel turns: kilometres within ±1–1.5%, depending on the tyre circumference | same as left | same as left | same as left | same as left |
| Road surface | ✓One value per turn, about every 2 m; on the rear hub the chain muddies it a little | ↑Cleaner: the hub knows when you pedal and removes the chain noise | same as left | ↑No chain up front, and front and rear can be compared | same as left |
| Impacts and potholes | ✓When, where (about 2 m) and how hard, up to 16 g | same as left | ↑How much reaches the rider | ↑Front or rear | same as left |
| Elevation and climbing | ✓From the barometer: about 10 cm resolution, ±1–2 m per climb; weather changes during the ride still need correcting | same as left | same as left | same as left | same as left |
| Gradient | ✓From the barometer, ±1% over 100 m | same as left | ↑Metre by metre, ±0.5–1% | same as left | same as left |
| Braking and acceleration | From speed, turn by turn | same as left | ↑Instantaneous, ±0.02 g | same as left | same as left |
| Energy into the brakes (pad wear) | ✓An estimate on descents | ↑It knows when you're not pedalling | same as left | same as left | ↑Complete: pedalling is taken out |
| Power | ✓Estimated from physics, with a 20–30 % error | same as left | ↑A little better, with the real gradient | same as left | ↑Measured, ±1–2 % |
| Drivetrain wear | Total kilometres only | ↑Kilometres per sprocket and chainring, cross-chaining, shifts | same as left | same as left | ↑Weighted by the real force |
| Temperature | ✓Sensor ±0.2 °C; air ±1–2 °C, because the sun warms the case | same as left | same as left | same as left | same as left |
| Wet rides and stretches | ✓Yes or no, per ride and per stretch, with edges a few minutes late | same as left | same as left | same as left | same as left |
| Rides on a trainer | ✓Recognised, as long as the wheel turns | same as left | same as left | same as left | same as left |
| From the crank | |||||
| Cadence; pedalling or freewheeling | — | ✓±1 rpm, at every pedal stroke | same as left | same as left | same as left |
| Gear in use | — | ✓±1%: neighbouring sprockets are 7 to 17% apart, so they can be told apart | same as left | same as left | same as left |
| With a Garmin or Wahoo bike computer (sensor open) | Speed sensor | ↑Also a cadence sensor | same as left | same as left | same as left |
| From the frame | |||||
| Lean angle and jumps | — | — | ✓±1–2°; airtime ±5 ms | same as left | same as left |
| Standing or seated | — | — | ✓Yes | same as left | ↑With the watts standing and seated |
| Comfort and rear suspension | — | — | ✓The vibrations that reach the rider, and an estimate of when to have the suspension checked (to be verified) | same as left | same as left |
| Crash | — | — | ✓Detectable, still to be verified in testing; the alert goes through the phone | same as left | same as left |
| Heading | — | — | ✓Coming: compass ±5–10°, a sketch and not a route | same as left | same as left |
| From the front hub | |||||
| Fork | — | — | — | ✓How much it filters, and an estimate of when to have it checked (to be verified) | same as left |
| Skidding under braking | — | — | — | ✓Yes, turn by turn | same as left |
| Tyre losing air | — | — | — | ✓Yes, from the turns of the two wheels (the threshold is still to be measured) | same as left |
| Front and rear wear | — | — | — | ✓Tyres, rims and bearings, tracked separately | same as left |
| With a power meter | |||||
| Where the watts go (surface, suspension, air) | — | — | — | — | ✓Estimates |
| Training (load, zones, kJ) | — | — | — | — | ✓Yes |
| Left and right, pedal stroke smoothness | — | — | — | — | ✓If the power meter sends them |
Coming with CrankPal Pro: the raw 9-axis data (accelerometer, gyroscope and magnetometer), at 16 bits and up to 1.66 kHz with one or two sensors connected, 833 Hz each with three or four. It's recorded on the phone and uploaded to DataLab over Wi-Fi.
“Resolution” is the step the data arrives in; the accuracy is in the table above.
| Data | Resolution | Units |
|---|---|---|
| Distance and speed | 1 turn (about 2.1 m); speed at every turn | km, km/h; on the wire, turns and time in 1/1024 s |
| Road surface | Every turn live; in the log, 64 stretches (about 270 m or more) and 8 classes | Index 0–100 and 5 bands; on the wire, energy per turn in g²·s |
| Impacts and potholes | Position to the turn; force in steps of 0.49 mg | g; impacts per ride |
| Elevation and climbing | One reading every 10 s (the barometer goes up to 75 Hz); steps of about 2 mm, noise of about 6 cm | m; whole metres in the log, pressure in 0.1 Pa on the environment channel |
| Gradient | 0.1 % | % |
| Braking and acceleration | Every turn; from the frame 417 times a second | m/s² |
| Energy into the brakes (pad wear) | Per descent | kJ |
| Power | Estimated every turn; measured every pedal stroke | W; from the meter, 1 W steps (Cycling Power) |
| Drivetrain wear | 1 turn per combination | km per sprocket and chainring; shifts |
| Temperature | One reading a minute (the sensor goes up to 10 a second) | °C; 0.01 °C on the environment channel, 0.1 °C in the log |
| Wet rides and stretches | Humidity every minute, ±2 %; up to 16 stretches per ride | km in the wet and stretches; humidity in % |
| Rides on a trainer | Per ride | Yes or no |
| Cadence; pedalling or freewheeling | Every pedal stroke | rpm; on the wire, turns and time in 1/1024 s |
| Gear in use | Every pedal stroke | chainring × sprocket |
| With a Garmin or Wahoo bike computer (sensor open) | Every pedal stroke | Bluetooth standard: turns and time in 1/1024 s |
| Lean angle and jumps | 0.1°; one sample every 2.4 ms | degrees; ms |
| Standing or seated | Per stretch | minutes standing and seated |
| Comfort and rear suspension | Per stretch; vibrations up to about 200 Hz | RMS m/s² |
| Crash | Event | time and place, from the phone |
| Heading | 1°, up to 200 times a second | degrees from north |
| Fork | Per stretch | % of vibration filtered |
| Skidding under braking | Every turn | event; % of slip |
| Tyre losing air | Per ride | % difference between the two wheels' turns |
| Front and rear wear | 1 turn | km per component |
| Where the watts go (surface, suspension, air) | Per stretch | W |
| Training (load, zones, kJ) | Every second | kJ, W, zones |
| Left and right, pedal stroke smoothness | Every pedal stroke | %; 0.5 % steps (Cycling Power) |
| Link | Ceiling | For the 9 axes |
|---|---|---|
| Chips | Accelerometer and gyroscope up to 6.66 kHz; magnetometer 1.5 kHz (200 Hz in normal mode); barometer 75 Hz; hygrometer 10 readings a second | Not the limit |
| Board bus (I2C at 400 kHz, shared by the four chips) | About 35 kB/s usable | The first limit: accelerometer and gyroscope fit up to 1.66 kHz (23 kB/s), not at 3.33 kHz |
| Bluetooth to the phone | About 35–50 kB/s at 1 Mbit/s, about 75 kB/s at 2 Mbit/s, shared by all connected sensors | One sensor at 1.66 kHz sends about 22 kB/s: one or two fit, with three or four it drops to 833 Hz each |
| The phone recording | Speed is not a problem | Storage is: about 80 MB per hour per sensor, to be compressed and uploaded to DataLab over Wi-Fi |
| CR2032 battery | The magnetometer at 1.5 kHz alone draws 2.2 mA | With raw data always on, 9 axes at 1.66 kHz and the magnetometer at 200 Hz: about 2–3 months at an hour a day (estimate). That's why raw data is sent in windows |
On the hub the gyroscope hits full scale above about 43 km/h, because it spins with the wheel; on the crank and the frame it doesn't. The phone's GPS track stays at one point per second: the raw data lines up with it in time, without making it any finer.
Design values, from the datasheets of the board's components, from physics and from the simulator: nothing has been measured on the sensor yet, and the final figures will come from road tests of the first sensors. Wear estimates are forecasts: the diagnosis stays with the mechanic.
With CrankPal Pro every ride recorded by your phone also has its raw and processed data: to look at, to download as CSV, JSON, GPX, FIT and .mat, and to analyse with a built-in tool or in MATLAB Online, surface trends included.
If you work in MATLAB: every ride also downloads as a .mat file, with the series already named (time, distance, speed, elevation, gradient, roughness, wet). And with one click DataLab publishes the ride and a sample script to a GitHub repository and opens it in MATLAB Online, in the browser, with nothing to install: a MathWorks account is required.
Tuesday 8 September 2026 · 07:12 · CrankPal Sensor on the rear hub
| t | km | km/h | elev. | grade | roughness | wet |
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You need at least one CrankPal Sensor, and the subscription is activated from the app. Expected launch prices, in euros.
Yes: Pro unlocks what the sensor can measure. Without the sensor the CrankPal app stays as it is, with forecasts from your phone, Strava and Garmin.
With the sensor, the ride log, the surface of every ride, lifetime odometers and updates stay free. Pro adds live telemetry, the full profile, the surface map, impacts and potholes, the extra sensors and DataLab.
It's always the same CrankPal Sensor: the first on the rear hub, the second on the crank arm, the third on the frame, the fourth on the front hub. The app pairs them to the same bike and tells you where to put them; a Bluetooth power meter can be added on top.
Yes. The monthly plan can be cancelled whenever you like; the yearly one won't renew if you cancel before it expires.
Together with the sensor. Leave your email with “Notify me” and we'll write when it can be activated.