Originally Posted by
Longfemur
But I have to say, I've never had trouble with a pump head on the threaded ones either. Are you sure there isn't something wrong with how tightly the rubber in the head is compressed down by the cap which screws down on it?
Yeah, seems there's something wrong here, either with the pump, or maybe the valve hole in the rim has too sharp an edge, or something. I've never had this problem in many years and with many different pumps.
BTW the little nut isn't entirely useless - I find that it facilitates getting the pump on when the tube is deflated (i.e. after a tube repair or change).