Puncture/schrader valve/pump question

[Premal P. Vora]

The front tire on my road bike has a puncture. I have a Schwinn pump
that has two outlets to accomodate regular valves as well as schrader
valves. While the tube is inside the tire, I am able to attach my pump
to the schrader valve on this bike and fill the tube with air (of
course, thanks to the puncture, it promply empties) -- I have no idea
how the pump figures out it's supposed to pump air from the schrader
outlet and not the other one.

To repair the puncture, I took the tire off the rim, and removed the
tube. Now, when I try to pump the tube with air, the pump only pumps
through the wrong outlet (the schrader has been opened to let in air).
Weird.

Any suggestions? Thanks in advance.

-Premal

 

[Premal P. Vora]

Quick correction: This bike has a presta valve not a schrader valve --
sorry!



Premal P. Vora wrote:
> The front tire on my road bike has a puncture. I have a Schwinn pump
> that has two outlets to accomodate regular valves as well as schrader
> valves. While the tube is inside the tire, I am able to attach my pump
> to the schrader valve on this bike and fill the tube with air (of
> course, thanks to the puncture, it promply empties) -- I have no idea
> how the pump figures out it's supposed to pump air from the schrader
> outlet and not the other one.
>
> To repair the puncture, I took the tire off the rim, and removed the
> tube. Now, when I try to pump the tube with air, the pump only pumps
> through the wrong outlet (the schrader has been opened to let in air).
> Weird.
>
> Any suggestions? Thanks in advance.
>
> -Premal

 

[[email protected]]

On 13 Oct 2006 11:45:23 -0700, "Premal P. Vora" <[email protected]>
wrote:

>The front tire on my road bike has a puncture. I have a Schwinn pump
>that has two outlets to accomodate regular valves as well as schrader
>valves. While the tube is inside the tire, I am able to attach my pump
>to the schrader valve on this bike and fill the tube with air (of
>course, thanks to the puncture, it promply empties) -- I have no idea
>how the pump figures out it's supposed to pump air from the schrader
>outlet and not the other one.
>
>To repair the puncture, I took the tire off the rim, and removed the
>tube. Now, when I try to pump the tube with air, the pump only pumps
>through the wrong outlet (the schrader has been opened to let in air).
>Weird.
>
>Any suggestions? Thanks in advance.
>
>-Premal

Dear Premal,

Push the tube against the base of the tire valve to provide
resistance:

|
___ |____

_________
^
|
push tube upward against bottom of valve

Cheers,

Carl Fogel

 

[Leo Lichtman]

<[email protected]> wrote: Push the tube against the base of the tire
valve to provide resistance: (clip)
^^^^^^^^^^^^^^^^^
The first thing I would do is try it on the other tire (that is still
inflated) to make sure it is working okay. Presta stems usually are held to
the rim by a nut, so when you apply the connector, the stem is firm. With
the tube off the rim, I'll bet you are not inserting it far enough to
actuate the mysterious linkage to close off the Shraeder opening. This is
consistent with what Carl V. said.

 

[[email protected]]

On Sat, 14 Oct 2006 02:22:32 GMT, "Leo Lichtman"
<[email protected]> wrote:

>
><[email protected]> wrote: Push the tube against the base of the tire
>valve to provide resistance: (clip)
>^^^^^^^^^^^^^^^^^
>The first thing I would do is try it on the other tire (that is still
>inflated) to make sure it is working okay. Presta stems usually are held to
>the rim by a nut, so when you apply the connector, the stem is firm. With
>the tube off the rim, I'll bet you are not inserting it far enough to
>actuate the mysterious linkage to close off the Shraeder opening. This is
>consistent with what Carl V. said.

Dear Leo,

Sorry, I wasn't clear--the idea is to seal the base of the Schrader or
Presta valve and provide back pressure.

Twin-head air chucks work by air resistance. If there's not enough
back pressure to trip the valve (an empty inner tube), the wrong
outlet may stay stubbornly open.

Usually, pressing the tire and tube flat against the base of the valve
provides enough back pressure to trip the annoying valve and make it
notice which outlet you want to use.

Ryan Cousineau explained this gentle push-the-tube-against-the-base
trick that provides back pressure and cured me of my more enjoyable
habit of giving the recalcitrant twin-head chuck a brisk whap with the
handiest tool to wake it up.

Cheers,

Carl Fogel

 

[Premal P. Vora]

HOORAY! ... this worked like a charm ... thanks!


>
> Dear Premal,
>
> Push the tube against the base of the tire valve to provide
> resistance:
>
> |
> ___ |____
>
> _________
> ^
> |
> push tube upward against bottom of valve
>
> Cheers,
>
> Carl Fogel