Angular rate
Gyroscope
Gyroscopes measure angular velocity. Integrating angular rate provides short-term orientation change, but bias and drift accumulate over time.
Pacerift / Lean Angle Guide
PILLAR 02 Riding Dynamics & Physics
Motorcycle lean angle: what it means and how it is measured.
Lean angle describes motorcycle roll relative to vertical during a turn. Estimating it from mobile sensors is a sensor-fusion problem because gravity, lateral acceleration, vibration, phone movement and chassis rotation are all present in the raw signal.
Answer first
A phone can estimate lean-related motion from its accelerometer and gyroscope, but phone motion is not automatically the same as motorcycle roll. Mounting, body movement, dynamic acceleration, calibration and frame alignment all matter.
01 How It Works
Three signals. One estimate.
Specific force
Accelerometer
The gravity vector can provide an orientation reference, but cornering and braking add dynamic acceleration. A single accelerometer sample cannot simply be treated as “gravity only.”
Trajectory
GPS
GPS contributes position and speed context. It is slower and noisier than an IMU for high-frequency motion, but useful for bounding drift and reconstructing the route.
02 Failure Modes
Why phone placement matters.
| Issue | Sensor effect | Why it matters |
|---|---|---|
| Phone slip | Device rotates independently of chassis | Device roll can diverge from motorcycle roll |
| Cornering G | Lateral acceleration changes measured specific force | Gravity cannot be inferred from one raw sample |
| Engine vibration | High-frequency acceleration | Creates spikes requiring filtering |
| GPS jitter | Position noise | Can distort trajectory and speed estimates |
| Rider movement | Phone and body move independently | Reference frame can become less stable |
03 Pacerift
From phone telemetry to a dedicated reference frame.
Pacerift's current product combines phone-first ride telemetry with a longer-term Pod direction. The Pod is positioned around six-axis absolute telemetry and a more rigid chassis reference, intended to support richer lean, cornering and pitch analysis.
Today
Android app using the sensors already inside the phone for ride recording, GPS route data and motion analytics.
Pod direction
A rigidly mounted telemetry unit can align its sensor axes to the motorcycle and reduce ambiguity introduced by phone movement.
A larger lean angle is not automatically faster or safer. Telemetry is best used to understand repeatability and riding dynamics.