Radhaltung

How do you sit on your bike?

Enter your body measurements and your bike’s numbers – Radhaltung turns them into your riding position. See it as a realistic 3D model and change the settings to watch what happens to your posture.

Work out my position Two body measurements, your frame’s numbers — and you see how you sit. Where does it hurt? Which structure sits there, what it hangs on, and what is worked with at that spot. Compare bikes Two frames side by side: how you sit on each, and what changes.

• Calibrated on real bikes — not just on rules of thumb. Three measured bicycles, matched to within a millimetre and a half.
• No sign-up, no cookies, no database. What you enter lives in this page’s address and nowhere else.
• Free and without advertising. Radhaltung is an independent project and stays usable without signing up.

What this page does not do: it makes no diagnosis and does not tell you where your trouble comes from — only someone who can look at you can do that. It counts no kilometres and no watts.

It does not replace a bike fitting. A fitter watches you pedal — where you compensate, how steady your pelvis stays, what is left of your mobility at the end of a long ride. This page sees none of that; it works from measurements. What it can do is make the invisible visible: which number hangs on which, what a centimetre of saddle height does at the knee, why a frame is too small. So it is not meant to keep you away from a fitter, but to send you there with better questions.