How do I take a good photo?#
Place the camera at hip / top-tube height, at 90° directly from the side, and keep it level. Wear tight-fitting kit or dark clothing against a light background, and put the pedal at 6 o'clock (bottom of the stroke). The in-app checklist and alignment guide walk you through it.
Why was my photo rejected?#
Pedalyze checks every photo before it measures anything. If the camera is off-axis, tilted more than about 4°, the rider is cropped, or joints are hard to see, the photo is rejected instead of silently measured wrong. The report tells you exactly what to fix before you retake it.
How accurate is Pedalyze?#
Pedalyze has not been validated against a goniometer yet. The knee-flexion target is based on Holmes, Pruitt and Whalen (1994); the other ranges are our own reading of published guidance. A photo more than about 4° off level is rejected, and a joint the model is not sure about is shown but not judged. KOPS uses your ankle as a pedal-spindle proxy, so it reads slightly rearward of a true plumb line.
Can Pedalyze replace a bike fit?#
No. It is a first check for the common issues: saddle height, reach, bar drop. If you have pain that lasts after rides, an injury, a clear difference between your left and right legs, or you race at a high level, see a professional bike fitter or a physio. You can share your report with them.
Where do your target ranges come from?#
Knee flexion is the one range with a clear published source: Holmes, Pruitt & Whalen, "Lower Extremity Overuse in Bicycling" (Clinics in Sports Medicine, 1994) recommends 25–30° of knee flexion at the bottom of the stroke; we use 25–35° for road because a single 2D photo cannot resolve a few degrees of ankle movement. KOPS is a fitting convention with no biomechanical law behind it — we keep it because it is reproducible, and we flag that we use the ankle as a spindle proxy. The hip, torso, elbow and shoulder bands, and the comfort and TT profiles, are our own reading of widely published road, comfort and TT fit guidance rather than any one certified protocol. We are independent: no affiliation with, or endorsement by, Retül, Steve Hogg, BikeFit or any fitting school. Every range is plain data in the open source file reference_ranges.yaml, so you can read the exact numbers we judge you against.
Which bikes and positions does Pedalyze support?#
Three fit styles: road/endurance, comfort/upright and TT/triathlon. You pick one before the analysis, and Pedalyze compares your angles with the target ranges for that style. Photos and clips must be taken side-on.