I had not thought about just sliding onto the minor diameter, and it seems to work. Learning still, at Medicare age!
But, here's something else I learned all by myself. My floor pump was bought as much for the gauge near the top as anything else. but it has another useful feature: a pressure release push button. Releasing the pressure on the hose and chuck sure makes it easier to pop the chuck off the tire.
harvey sachs mcLean va. +++++++++++++++++++++++++++++++++ David Snyder wrote: Various Presta heads (chucks) that I encounter "in the field" often have sealing issues.
What I've noticed is that many, if not most Presta heads are designed specifically to fit only onto the minor-diameter threaded portion of a Presta valve. This requires a delicate touch while fitting the chuck.
Once they've been forced onto the major diameter (threaded or un-threaded) portion of the Presta stem, they may no longer give a tight seal on the smaller threads (which the valve's plastic cap threads onto). This applies to both "push-on" and "locking" presta heads.
With use and/or age, most Presta chuck washers seem to suffer this fate. One byproduct of this is that for a given level of sealing power (read p.s.i.), the chuck will require much more force to remove from the larger of the two outside-diameter portions of the stem, doubly stressing the tube's rubber where it's bonded to the stem metal.
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