Every cyclist I know has done this. Your knee aches a bit. You raise the saddle. Two rides later your hips are rocking, so you drop it. Not all the way back — a bit less than where it was. Then you forget what the original height was, and you have no idea whether anything actually improved or you just got used to it.
That was me for about two years. Two millimetres at a time, in the dark.
A real bike fit solves this, and if you can afford one, go and get one — a good fitter will see things a camera cannot. But most people never will. So they do what I did: guess, adjust, guess again, and quietly hope.
Bike Fit Analyzer is my attempt at giving those people a number to hold on to. You film yourself pedalling from the side. It finds your joints, measures your knee, hip and back angles through the pedal stroke, and grades them against the ranges that bike-fitting research actually uses. Then you can change one thing, film again, and see whether it moved.
Two things I want to be honest about.
Your video never leaves your device. It is analysed in your browser. I do not upload it, I do not keep it, and I never see it. That was not a feature I added later — it is the reason the thing is built the way it is. Nobody should have to send a video of their body to a stranger to find out if their saddle is too high.
It is not a bike fit, and it is not medical advice. A phone camera sees two dimensions. It cannot see your ankle rolling, your leg-length difference, or the old injury you are riding around. If something hurts, go and see a physio, not a website. I put this in the terms and I mean it outside the terms too.
It is free, and the source is public so you can check that I am telling the truth about the video.
