Dual valve floor pump only pushes air out the Schrader valve hole

[Brad Ford]

I've got a cool little Wrench Force floor pump that will accept
Schrader or Presta. I've used it for over a year exclusively to
inflate my Presta road tubes. Got the kids bikes for Christmas, pumped
them up (Schrader valves), and now (several weeks later) the pump won't
blow air out the Presta hole any more. It's supposed to be "auto
sensing". Is it just buggered? What would you all try to debug this
problem?

[diann...@yahoo.com]

I've had the same problem with my Wrench Force pump. Quite annoying!

It's especially bad when trying to inflate from 0, e.g. a completely
empty inner tube. It seems to me that the pump sometimes "corrects
itself" if I install it on a partially inflated tube.

Otherwise I get frustrated and bang the pump head on something hard
until it behaves.

If it keeps it up I'd ask for a new head from the dealer. They're easy
to remove and replace without tools.

Good luck!

[James Scott]

I have a similar WF pump, and have had a similar problem. It's most
noticeable when inflating a new presta tube. I've had good luck with
either blowing a little air into the tube by mouth or pushing the valve
stem into the pump far enough to force the valve open by contact rather
than relying on air pressure.

JLS

[Brian Huntley]

My Beto brand floor pump sometimes balks at starting to inflate a
Presta tube. I find if I put my finger against the tube's valve (from
the far side) to increase the back-pressure, the pump catches on and
inflates it properly.

[Mike Jacoubowsky]

It's a fairly common problem with the one-head pump designs. You can often
get it to work if you strike the head against the ground pretty sharply,
which unsticks the internal gadget that detects which valve is in use. But a
new pump hose will probably take care of the problem too, and it's quite
likely to be considered a warranty issue.

As others have mentioned, this typically happens only when there's zero air
in the tube, so inflating just a tiny amount with a hand pump will usually
work. Someone else suggested blowing a bit of air into the tube by mouth,
but I've tried that a couple times without success.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

[Luke]

In article <1139026784....@g43g2000cwa.googlegroups.com>,
Brian Huntley <brian_...@hotmail.com> wrote:

> My Beto brand floor pump sometimes balks at starting to inflate a
> Presta tube. I find if I put my finger against the tube's valve (from
> the far side) to increase the back-pressure, the pump catches on and
> inflates it properly.

I've had the same problem with my Beto for about 2 years; and have been
the using the workaround you described - works every time.

Luke

[damyth]

There is no need to hit anything on these chucks. Simply cover the
valve hole that you intend to use with your thumb, and start pumping.
The back pressure will "free" the valve to the correct postion. You
can then mount the chuck on the tube valve (even if there is no air in
the tube) and start pumping successfully.

[Brad Ford]

Thanks all for your suggestions. I got the WF pump to un-Schraderize
itself by inserting the valve, and holding my thumb against the back
side of the tube (the side opposite the valve) while pumping with my
other hand.

-B.

[ajhu...@gmail.com]

Worked for me too on a beto. Thanks everyone!

[walm...@gmail.com]

Thank for taking the time to post the tip.
It is appreciated.

[esdon...@gmail.com]

I had let my road bike tires go completely flat then encountered the same problem when I tried to inflate them, with a different brand of dual-valve floor pump that had always worked until then. I tried the trick of covering the open Schrader valve with your thumb, but it didn't work for me. It did cause a lot of pressure on my thumb and some very entertaining noises when air squeaked out! What ultimately worked was to inflate the tires of another bicycle (which also uses Presta valves) which had mostly full tubes already, then go back and inflate the flat road bike tires. It seems that persuaded the pump to switch back to its Presta setting. Good luck to all!

[gme...@gmail.com]

You dont cover the open schraeder valve, you loosen the nut holding the presta stem to the bike wheel so you can press the valve stem through to the tire side. When you can feel it through the tire then press on the tire side so that pressure can build inside the valve stem while operating the pump. This causes the auto valve to lock out the schraeder side of the pump head.

[Andre Jute]

Rather than all these tiresome workarounds, why not just buy an SKS Rennkompressor? Works right every time. Trusted by TdF mechanics. Fully rebuildable with universally available spares, as it has been for half a century.

Andre Jute
If it's good enough for me, it's good enough for you

[Emanuel Berg]

Andre Jute <fiul...@yahoo.com> writes:

>> I've got a cool little Wrench Force floor pump that
>> will accept Schrader or Presta. I've used it for
>> over a year exclusively to inflate my Presta road
>> tubes. Got the kids bikes for Christmas, pumped
>> them up (Schrader valves), and now (several weeks
>> later) the pump won't blow air out the Presta hole
>> any more. It's supposed to be "auto sensing". Is it
>> just buggered? What would you all try to debug
>> this problem?
>
> Rather than all these tiresome workarounds, why not

> just buy [...]

Buy stuff. Solution #1 in the bicycle world.

--
underground experts exiled

[Andre Jute]

On Friday, July 20, 2018 at 9:01:39 PM UTC+1, Emanuel Berg wrote:

Oh, I agree with you; I have nothing but contempt for bicycle fashion victims. That's why I mention the SKS Rennkompressor, probably the most old-fashioned pump still on the market. I bought two SKS Rennkompressors about ten years ago and haven't bought a pump since. What matters is not how often you buy, but how smart you buy.

Andre Jute
Function is value, not fashion

[Emanuel Berg]

Andre Jute <fiul...@yahoo.com> writes:

>> Buy stuff. Solution #1 in the bicycle world.
>
> Oh, I agree with you; I have nothing but contempt
> for bicycle fashion victims. That's why I mention
> the SKS Rennkompressor, probably the most
> old-fashioned pump still on the market.

Obviously you like things that work, be it new or old,
but be it functionally equivalent, I like the old
things the more, and old stuff (that works) I have
noticed tends to impresse outside people much more.

I really don't know why, maybe they think "here is
a machine that has been used by tons of people who
knows there stuff, and it has been used the right way,
and cared for the right way, so it still works".
With new things, maybe people think "OK, so this is an
item anyone can buy, anyone who does something
successfully enough, something that probably is
something I don't understand or respect".

Or perhaps this is over-analyzing, perhaps people just
like the industrial romantics of the lost industrial
age in our countries.

I have noticed even females like old machines and they
are not the people to be into gear and equipment
otherwise, well the majority of them at least.

--
underground experts exiled

[slto...@gmail.com]

The pump head isn't deep enough for the Presta valve so sometimes it doesn't form a seal if you have your bike in the stand. It most definitely IS a good pump but it does have some problems too. And you have to turn the "lock" in the correct direction for Presta or Schrader. Now that I've had that concussion it's sometimes difficult to remember which way locks which valve.

[bills...@gmail.com]

this has worked out for me. Thanks Bill

[Frank Krygowski]

Is anyone keeping track of the oldest zombie threads? This one rose from
the dead after about 12.8 years.

I wonder what the record is?

--
- Frank Krygowski

[Sir Ridesalot]

2 ppost in 2016 and 1 in 2017.

Cheers