Art Harris said:After the previous thread on frame fit pumps that can be installed
under the top tube using a pump peg, I got myself a brand new Zefal
HPX-4 pump with the ASV (Auto Select Valve) feature.
Out of the box, it seems to work fine with my Presta valves. I just
press the head onto the valve with the thumblock lever parallel to the
pump. Then I flip the thumblock perpendicular to the pump and start
pumping. I can get ~100 psi without too much trouble.
I've read several reviews online that say Presta users should open the
pump head and flip a plastic piece around to improve performance. Some
even say the pump won't work at all with Presta valves if this isn't
done.
What experiences have others had with this pump and Presta valves?
Will I get easier pumping if I do the flip?
Older versions of Zefal pumps came in either Schrader
or Presta versions. Then they made a version where
you can convert it between Schrader and Presta by
unscrewing the chuck cover and flipping around
the rubber chuck and plastic pin (the pin is needed to
depress the Schrader check valve). Now, I guess, they
make a version that auto converts somehow, and
that's what you have. The Zefal HPx has been around
for at least 20 years, I think, so it's no surprise that
reviews are outdated.
Your pump works on a Presta valve, so the reviews that
say it won't work unless you flip the piece around are
clearly inapplicable, so, excuse me for asking, why are
you stressing about what some random internet review
says? This is not rocket pump science. Generally,
a pump either seals on the valve and gets air into the
tire, or it doesn't. The issue with the HPx is that you're
supposed to remember to turn the end cap from X to HP
when pumping so you don't have to push against the
spring. Which is in the instructions, I believe.
Ben
