Zefal HPX ASV Pump and Presta Valves

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?

Thanks,
Art Harris

"Art Harris" wrote in message
...

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.

This takes a minute and has been necessary for decades. It isn't much
trouble and medium to high value Presta valve bikes aren't that common
anyway.

What experiences have others had with this pump and Presta valves?
Will I get easier pumping if I do the flip?

You cannot fit the pressure head over a Presta valve unless you flip the
seal. You also have to flip the Presta valve pin which pushes in the Presta
valve head so that you don't have to pump against the spring pressure as
well.

"Tom Kunich" cyclintom@yahoo. com wrote in message
m...
"Art Harris" wrote in message
...

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.

This takes a minute and has been necessary for decades. It isn't much
trouble and medium to high value Presta valve bikes aren't that common
anyway.

What experiences have others had with this pump and Presta valves?
Will I get easier pumping if I do the flip?

You cannot fit the pressure head over a Presta valve unless you flip the
seal. You also have to flip the Presta valve pin which pushes in the
Presta valve head so that you don't have to pump against the spring
pressure as well.

Hi Tom,
Did you mean Schrader wherever you wrote Presta?
Thanks,
Kerry

On Jun 13, 12:45*pm, Art Harris wrote:
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

"Kerry Montgomery" wrote in message
m...

Hi Tom,
Did you mean Schrader wherever you wrote Presta?

DUHHHHHH - of course, thanks for the correction.

Ben wrote:
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.


No, the reviews I'm referring to are for the current "ASV" version.
And from people who post here and who I respect.

http://www.amazon.com/review/product...View points=1

I've been using the old style HP pumps for decades, and am familiar
with having to configure them for either Schrader or Presta valves.
That's why I'm curious why some folks think the new "automatic"
version needs to have the chuck reversed.

Art Harris

"Art Harris" wrote in message
...

I've been using the old style HP pumps for decades, and am familiar
with having to configure them for either Schrader or Presta valves.
That's why I'm curious why some folks think the new "automatic"
version needs to have the chuck reversed.

Hmm, I've bought HP pumps within the last year that worked exactly the same
as they have since the dawn of time.

Tom Kunich wrote:
Hmm, I've bought HP pumps within the last year that worked exactly the same
as they have since the dawn of time.


This is the new version:

http://tinyurl.com/6fkpqo

Art Harris

On Jun 13, 3:31*pm, Art Harris wrote:
Ben wrote:
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.

No, the reviews I'm referring to are for the current "ASV" version.
And from people who post here and who I respect.

http://www.amazon.com/review/product...top_cm_cr_acr_...

I've been using the old style HP pumps for decades, and am familiar
with having to configure them for either Schrader or Presta valves.
That's why I'm curious why some folks think the new "automatic"
version needs to have the chuck reversed.


I see that I was wrong and they may have managed
to improve it downward. It sounds like you're the only
one here with the new version, and since you're
familiar with the old version, I expect you can take it
apart and put it back together without difficulty.
So it's probably up to you to figure out whether this
mod still reconfigures it for Presta.

I don't own any pumps that automagically reconfigure
Schrader/Presta. I do have two pumps that have a
twinhead with opposite Schrader/Presta chucks, which
is convenient, and I don't really see how automatic
heads are an improvement on that. But they haven't
been asking me.

Ben

"Art Harris" wrote in message
...
Tom Kunich wrote:
Hmm, I've bought HP pumps within the last year that worked exactly the
same
as they have since the dawn of time.

This is the new version:

http://tinyurl.com/6fkpqo

Thanks Art. Sure enough - I've never seen that before.