Originally Posted by
frankenmike
If you have very deep rims, most valve extenders only work on threaded valves.
I believe the "unthreaded" valve stems are still threaded at the tip, which is where valve extenders and the plastic valve caps thread on.
Originally Posted by
Al1943
Michelin invented bicycle "balloon" tires and tubes. All Michelin tubes are unthreaded, and less damaging to your pump chuck O-ring.
At least some of Michelin's 26" tubes have threaded stems, because that's what I have on my commuter right now.