Originally Posted by
BobbyG
I like how the presta valves screw shut and have a threaded ring to tighten against the rim.
You know that most people throw that nut away when you install the tube, right? You can never get it tight without pulling the tube right into the hole in the rim, which of course ruins the tube. Its only purpose is to keep the stem from being pushed into the rim when you try to inflate a flat tire - which can be done by pushing it back out from the other side.
Presta valves aren't quite as fragile as they look. I've never broken one. One thing I do, though, is to make sure I'm pulling the chuck straight off it rather than just yanking at an angle. It's easier on the pump head that way, too.