Originally Posted by
rpenmanparker
If your adapter doesn't unseat the presta valve stem automatically, it can stick and prevent air going in. Don't empty the tire; just depress the valve stem quickly to unstick it. Then top off the tire.
Hmmm... I've been using presta valves for about 38 years and can't ever recall any pump head or adapter that "unseats the presta valve stem automatically". I always have to depress the valve to break it's seal before pumping up a tire. Any depressing of the valve stem, that you mention, would have to be automatic and momentary, or air wouldn't stay in the tube.
Could you enlighten me?