[CR] Using Presta chucks, was tire pressure gauge sought

(Example: Framebuilders:Pino Morroni)

Date: Thu, 06 May 2010 20:53:07 -0400
From: "Harvey Sachs" <hmsachs@verizon.net>
To: Classic Rendezvous <classicrendezvous@bikelist.org>, dddd@pacbell.net
Subject: [CR] Using Presta chucks, was tire pressure gauge sought


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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