Bike Fit Analyzer
Stop guessing your saddle height.
Film 20–30 seconds of pedaling and every fit angle comes back green, amber or red, with what to change. Runs in your browser — nothing is uploaded.
A rider ran their first clip through it and went away to raise their saddle. @paceandpedal_ on Threads ↗
How it works
How the bike fit analysis works
Google's MediaPipe Pose does the tracking, entirely on your own device.
Film your ride
Camera square to your side, about hip height. Pedal steadily for 20–30 seconds — a turbo trainer gives the most consistent result.
AI tracks your joints
Shoulder, elbow, hip, knee and ankle are found in every frame. It picks the side facing the camera and skips frames that aren't clear enough.
Get graded advice
Every angle is compared against the ranges used in bike fitting, then explained in plain language.
What good looks like
What a good bike fit looks like
A good fit is not only about power — it is what keeps you comfortable and in control.
Knee at the bottom
30–40°Still slightly bent at the bottom of the stroke. Too much bend means the saddle is low; nearly straight means it's high — that's when the hips start rocking.
Back / torso angle
40–50°Low enough to be efficient and aero, but high enough to breathe and stay comfortable for the length of your ride.
Elbow bend
15–30°Never locked straight. A slight bend absorbs vibration and takes pressure off your hands.
Reach to the bars
80–95°A reach that fits keeps your shoulders relaxed, without feeling stretched out or cramped.
Stable hips
from the rearLevel, with no side-to-side rocking. Rocking usually means the saddle is a touch too high.
Knee tracking
from the frontKnees driving straight up and down over the pedals, not diving in or bowing out — a cleat and stability cue.
Every measurement in detail, view by view: how the analyzer works.
Honest comparison
This tool vs. a professional fit
They are not competitors. Run this first, then walk into a fitting knowing what to ask.
| This tool | A professional fit | |
|---|---|---|
| Cost | Free, as many clips as you like | Paid — varies by studio and country |
| Where | Your phone or laptop, at home, in minutes | A studio, usually a two to three hour session |
| What it sees | Joint angles from a 2D side, front or rear clip | Your body in 3D, plus pressure mapping, cleats and foot support |
| How precise | Within a few degrees. Knee is the most reliable, reach the least | Precise, and with a fitter watching you actually ride |
| What you get | A saddle-height change in mm, and which way your reach and bar height are off | All of that, plus the parts that would fix it and someone fitting them |
| Best for | Catching an obviously wrong saddle height before you spend anything | Pain, injury, racing, or setting up a new bike |
FAQ
Frequently asked questions
Is my video uploaded anywhere?
No. Pose detection and every calculation run in your browser. Nothing is uploaded, and no account is needed.
Which bikes does it work with?
Almost any — road, MTB, gravel, TT/triathlon, hybrid, commuter or e-bike. It measures your body, not the bike, and the target angles follow the bike type you pick.
How accurate is it?
Enough to catch the obvious problems, like a saddle that's too high or too low. Knee is the most consistent reading, reach the least. It's 2D, so it can't replace a professional 3D fit.
What kind of clip should I film?
20–30 seconds, camera square to your side at hip height, pedaling as you normally would. A trainer and decent light make it more consistent.
Does it work on my phone?
Yes, in any modern browser. Devices with WebGPU are faster; older ones fall back to the CPU and still work, just slower.
Is it free? Can I see the code?
Free, and the full source is published so you can check the privacy claims yourself — read the code on GitHub. It's source-available, not open source: read it, learn from it, use the tool — just don't build a competing product from it.
Can it replace a professional bike fit?
Not yet. It's a basic check to run before you adjust anything yourself or book a fitter. If you have pain or specific fitting needs, see a professional.
Guides
Read this before you move anything
What the numbers mean, what to change first, and where this kind of measurement stops being reliable.
How to film a clip that measures accurately
Camera height, camera angle and clip length — plus the four filming mistakes that quietly cost you several degrees.
The four angles, and where the targets come from
Knee, torso, elbow and shoulder: what each one is a proxy for, and why published numbers disagree by about 8°.
Your report says red — what to adjust first
Start with the free adjustments, change one thing at a time, and know when to leave the bike alone.
What 2D video can and cannot tell you
A few degrees of measurement noise, no cleat or pressure read, and why the front and rear views are still beta.
Versi Bahasa Indonesia ada di bike fitting dari video, tinggi sadel, nyeri lutut, and sakit punggung dan leher. All guides →
On Threads
People are already riding with it
A rider's first run with the analyzer, and the post it launched from.
Ready to see your numbers?
Drop a clip and get a graded read in under a minute — free, in your browser.
Launch the analyzer