Presta valve sticks.

Michael Press said:

One of my presta valves sticks. Even though I push it
before connecting the pump chuck, it requires
over-pressure of approximately 50 psi to overcome the
sticky seat and inflate the tire. It does not get better.
I have considered various chemicals (water, detergent,
penetrating lubricant, light mineral oil) to fix it, but
prefer a tried-and-true solution. Anyone? or will I have
to throw away the tube when it gets too sticky to inflate?

All of my presta valves stick -- no biggie.

Peter Cole said:

Michael Press said:

One of my presta valves sticks. Even though I push it before
connecting the pump chuck, it requires over-pressure of approximately
50 psi to overcome the sticky seat and inflate the tire. It does not
get better. I have considered various chemicals (water, detergent,
penetrating lubricant, light mineral oil) to fix it, but prefer a
tried-and-true solution. Anyone? or will I have to throw away the tube
when it gets too sticky to inflate?

All of my presta valves stick -- no biggie.

Nope. I agree with the OP, My valves generally cause over-pressure of
ca. 1 bar (15 psi) before they open to let air in. In this strange case
we're talking about almost 4 bar over-pressure. So yes the valve is out
of spec.

If the tube (or tyre, if this is a single) is new, then return it for a
new one. If a worn single, then see if the valve core is replaceable.

I had this once on a new tube - I just got the LBS to swap it
(Continental latex).

/Robert

Peter Cole said:

All of my presta valves stick -- no biggie.

I have a bunch of IRC brand tubes and all of them do that. This is the
only brand I have encountered this problem with. Annoying but still
reliable.

-nate

Llatikcuf said:

Peter Cole said:

All of my presta valves stick -- no biggie.

I have a bunch of IRC brand tubes and all of them do that. This is the
only brand I have encountered this problem with. Annoying but still
reliable.

I don't think there are that many actual factories producing tubes, so
there's a lot of re-labeling. I find that virtually all the prestas I
use need to be tapped a couple of times before I pump. This may have
more to do with frequency of pumping than anything else. In any case, a
little stiction doesn't seem to hurt (unless you blow the gauge). It
doesn't cause over-inflation, just a jump in the needle.