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?

 

[[email protected]]

Brad Ford wrote:
> 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?

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]

Brad Ford wrote:
> 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?

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]

Brad Ford wrote:
> 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?

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]

> 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?

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 <[email protected]>,
Brian Huntley <[email protected]> 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]

Mike Jacoubowsky wrote:
> > 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?
>
> 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

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.

 

[lango6]

@damyth's solution worked fine, thanks.

 

[davereo]

I had this same problem with a Topeak Joeblow II pump. I contacted the manufacture and they mailed me a replacement head.

 

[briguy74]

As some of the other posts have mentioned this mostly happens when the inner tube is completely flat or with very little air in it. It seems for the auto value to work it needs a blast of air to come from the tube when you first connect it to properly switch to that valve. I've found what works is to shoot a short blast of air into the pump value you want to use, via a compressed air can or anything you have to blow a strong focused shot of air into the valve. Essentially mimicking the effect of putting the pump onto a fullish inner tube. Could maybe even try blowing with mouth. Then just connect and pump normally, should work. This is what worked for me!

Good luck!

 

[alienator]

As some of the other posts have mentioned this mostly happens when the inner tube is completely flat or with very little air in it. It seems for the auto value to work it needs a blast of air to come from the tube when you first connect it to properly switch to that valve. I've found what works is to shoot a short blast of air into the pump value you want to use, via a compressed air can or anything you have to blow a strong focused shot of air into the valve. Essentially mimicking the effect of putting the pump onto a fullish inner tube. Could maybe even try blowing with mouth. Then just connect and pump normally, should work. This is what worked for me! Good luck!

The problem with that is that with a presta valve, the pump doesn't get a "shot of air" when it's placed on the stem. It requires pressure from the pump to open the presta valve.