A Real Bike Fit, From Your Phone.

Bike Fast Fit measures rider position from high-speed video. The tracking is done by our own model, built and trained specifically for cyclists on bikes rather than adapted from a general-purpose pose network, and it follows the rider through complete pedal strokes at 240 frames per second.* That matters because a riding position is not a pose: knee, hip, and torso angles change through every pedal revolution, and a measurement taken from one frozen frame can land anywhere in that swing. Measuring across the full stroke yields the angles a rider actually cycles through, not a single arbitrary instant.

From that tracking, the app reports the measurements fitters actually use (knee angle at maximum extension, hip angle, torso and shoulder position) and compares them to recommended ranges. Our ranges draw on established fitting references and our own fitting data. The references are the published ranges professional fitters train on; our data is a database of real fitting sessions, including the before-and-after adjustments made by working fitters. Recommendations are presented as windows rather than single numbers, because that is what the evidence supports: a correct riding position is a range the rider settles into, not a point.