Originally Posted by lhbernhardt

If you ride the bike enough, riding no-hands just comes naturally. Mechanically, the bike just needs to be perfectly-aligned, with true wheels, and the headset needs to be adjusted with just enough preload, so it's a good test of headset adjustment. When you rise off the handlebars, a quick and very gentle shake of the hips should move the bars slightly and show you how much control you have over the steering. If the bike doesn't respond immediately, and starts to drift off to one side, it means your headset is too tight and you'd darn well better get those hands back on the bars! When you get back, loosen the headset preload slightly.