presta valve screws out

[Paul Nevai]

Another day, another surprise. I found out that the presta valve on one of my
tubes screws out. In fact, it screws out and the tube loses pressure
appr. one out of ten times when I screw of the little plastic valve cap from
it. I never knew that those cores can be screwed out and it appears that on
all but one of my tubes it can't be screwed out, and are in fact not even
separate pieces but are part of the valve stem.

Let me try to specify. It's not the "core" what screws out but the thing
which holds the core and which itself is screwed into the valve stem.

So when this thingie can be screwed out, is this a "lower" or "higher"
quality indicator.

Also, how can I screw it in so it would never ever screw out again, I tried
to wrap a rubber piece around it and then use a wise grip plier but I am not
sure it worked.

Thanks, Paul

 

[psycholist]

"Paul Nevai" <[email protected]> wrote in message
news:[email protected]...
> Another day, another surprise. I found out that the presta valve on one of
my
> tubes screws out. In fact, it screws out and the tube loses pressure
> appr. one out of ten times when I screw of the little plastic valve cap
from
> it. I never knew that those cores can be screwed out and it appears that
on
> all but one of my tubes it can't be screwed out, and are in fact not even
> separate pieces but are part of the valve stem.
>
> Let me try to specify. It's not the "core" what screws out but the thing
> which holds the core and which itself is screwed into the valve stem.
>
> So when this thingie can be screwed out, is this a "lower" or "higher"
> quality indicator.
>
> Also, how can I screw it in so it would never ever screw out again, I
tried
> to wrap a rubber piece around it and then use a wise grip plier but I am
not
> sure it worked.
>
> Thanks, Paul

I don't have any answers for you, but I share your frustration. I don't
know why some are made this way and some aren't. I suspect Jobst will chime
in and clarify this. Anyway, bonehead me left on a long ride a few weeks
back and had only one CO2 cartridge in my seat bag. I got a flat. I
changed it out. My wheels have deepish, semi-aero rims and I have to use a
valve extender to pump them up. So I've used my last CO2 cartridge to fill
the repaired tire and I go to remove the valve extender. The core of the
new tube unscrews with the valve extender and there I am ... stranded. I
live in a very rural area. I had a very long walk to get to where I had a
cell phone signal to be able to call home. I spent a lot of that time
wondering what possible reason there could be for the core of a valve to
unscrew like that. Never came up with one.

Bob C.

 

[mark]

"Paul Nevai" wrote ...
> Another day, another surprise. I found out that the presta valve on one of
my
> tubes screws out. In fact, it screws out and the tube loses pressure
> appr. one out of ten times when I screw of the little plastic valve cap
from
> it. I never knew that those cores can be screwed out and it appears that
on
> all but one of my tubes it can't be screwed out, and are in fact not even
> separate pieces but are part of the valve stem.

I discovered the same thing about a spare tube I was installing the other
day. The tube had an extra long valve stem to fit an aero or semi-aero rim.
I suspect that the removable valve lets the manufacturer install valves in
stems of varying lengths, according to consumer demand.
>

> So when this thingie can be screwed out, is this a "lower" or "higher"
> quality indicator.

Mine seems to be about the same quality as the valves on the other tubes I
buy.
>
> Also, how can I screw it in so it would never ever screw out again, I
tried
> to wrap a rubber piece around it and then use a wise grip plier but I am
not
> sure it worked.

I suspect that this would distort the valve or strip the threads, making the
whole thing useless. I got mine as tight as I could with my fingers, left it
at that, and made a note not to buy that brand of tube again.
--
mark

 

[david]

I believe the reason is, if you bend the valve, you can replace it. As for
tubulars, you can unscrew the valve, install an extension, and then screw
the valve into the extension piece. It makes for a far far better seal then
using the valve extenders that screw on over the valve fitting. Its a great
feature.

David

 

[[email protected]]

On 12 Sep 2004 13:44:43 GMT, [email protected] (Paul
Nevai) wrote:

>Another day, another surprise. I found out that the presta valve on one of my
>tubes screws out. In fact, it screws out and the tube loses pressure
>appr. one out of ten times when I screw of the little plastic valve cap from
>it. I never knew that those cores can be screwed out and it appears that on
>all but one of my tubes it can't be screwed out, and are in fact not even
>separate pieces but are part of the valve stem.
>
>Let me try to specify. It's not the "core" what screws out but the thing
>which holds the core and which itself is screwed into the valve stem.
>
>So when this thingie can be screwed out, is this a "lower" or "higher"
>quality indicator.
>
>Also, how can I screw it in so it would never ever screw out again, I tried
>to wrap a rubber piece around it and then use a wise grip plier but I am not
>sure it worked.
>
>Thanks, Paul

Dear Paul,

Sealant tubes use this design to allow pumping goo into the
tube.

If you're screwing a plastic cap onto a Presta valve so hard
that it unscrews a metal fitting, you may be using
considerablly more force than necessary.

I'm not recommending a torque wrench for valve caps, but
using two fingers and a lighter grip may help.

Carl Fogel

 

[psycholist]

<[email protected]> wrote in message
news:[email protected]...
> On 12 Sep 2004 13:44:43 GMT, [email protected] (Paul
> Nevai) wrote:
>
> >Another day, another surprise. I found out that the presta valve on one
of my
> >tubes screws out. In fact, it screws out and the tube loses pressure
> >appr. one out of ten times when I screw of the little plastic valve cap
from
> >it. I never knew that those cores can be screwed out and it appears that
on
> >all but one of my tubes it can't be screwed out, and are in fact not even
> >separate pieces but are part of the valve stem.
> >
> >Let me try to specify. It's not the "core" what screws out but the thing
> >which holds the core and which itself is screwed into the valve stem.
> >
> >So when this thingie can be screwed out, is this a "lower" or "higher"
> >quality indicator.
> >
> >Also, how can I screw it in so it would never ever screw out again, I
tried
> >to wrap a rubber piece around it and then use a wise grip plier but I am
not
> >sure it worked.
> >
> >Thanks, Paul
>
> Dear Paul,
>
> Sealant tubes use this design to allow pumping goo into the
> tube.
>
> If you're screwing a plastic cap onto a Presta valve so hard
> that it unscrews a metal fitting, you may be using
> considerablly more force than necessary.
>
> I'm not recommending a torque wrench for valve caps, but
> using two fingers and a lighter grip may help.
>
> Carl Fogel

Carl,

If you've ever used a valve extender, you know that you sometimes have to
screw them on pretty tightly to avoid having more of the air you pump in
exit via the threads instead of going into the tube. It can be a real trick
to screw them on tight enough for inflation, but loose enough that they can
be removed without coring the valve.

FYI,
Bob C.

 

[[email protected]]

On Sun, 12 Sep 2004 13:44:10 -0400, "psycholist"
<[email protected]> wrote:

>
><[email protected]> wrote in message
>news:[email protected]...
>> On 12 Sep 2004 13:44:43 GMT, [email protected] (Paul
>> Nevai) wrote:
>>
>> >Another day, another surprise. I found out that the presta valve on one
>of my
>> >tubes screws out. In fact, it screws out and the tube loses pressure
>> >appr. one out of ten times when I screw of the little plastic valve cap
>from
>> >it. I never knew that those cores can be screwed out and it appears that
>on
>> >all but one of my tubes it can't be screwed out, and are in fact not even
>> >separate pieces but are part of the valve stem.
>> >
>> >Let me try to specify. It's not the "core" what screws out but the thing
>> >which holds the core and which itself is screwed into the valve stem.
>> >
>> >So when this thingie can be screwed out, is this a "lower" or "higher"
>> >quality indicator.
>> >
>> >Also, how can I screw it in so it would never ever screw out again, I
>tried
>> >to wrap a rubber piece around it and then use a wise grip plier but I am
>not
>> >sure it worked.
>> >
>> >Thanks, Paul
>>
>> Dear Paul,
>>
>> Sealant tubes use this design to allow pumping goo into the
>> tube.
>>
>> If you're screwing a plastic cap onto a Presta valve so hard
>> that it unscrews a metal fitting, you may be using
>> considerablly more force than necessary.
>>
>> I'm not recommending a torque wrench for valve caps, but
>> using two fingers and a lighter grip may help.
>>
>> Carl Fogel
>
>Carl,
>
>If you've ever used a valve extender, you know that you sometimes have to
>screw them on pretty tightly to avoid having more of the air you pump in
>exit via the threads instead of going into the tube. It can be a real trick
>to screw them on tight enough for inflation, but loose enough that they can
>be removed without coring the valve.
>
>FYI,
>Bob C.

Dear Bob,

True, but the original post specifically complains about
plastic valve caps, not extenders.

As for valve extenders, I found them so annoying that I
switched to long valve stems after fooling around with
teflon tape to seal the threads.

Another problem is that the extender is just a hollow shell
that fits down over the real Presta valve, whose lock-nut
must be left unscrewed, leaving nothing but air-pressure to
seal the valve.

In addition to the obvious problem of losing air-pressure
without a lock-nut, the extender makes it hard to break a
stuck valve free.

This can cause two problems. First, you can't pump the tube
any further if the valve sticks on a mostly-filled tube.
Second, you can't let the air out to collapse a slow-leak
flat to remove the tire.

So you have to remove and replace the extender, an awkward
job, or else carry something to poke down into it to free
the hidden Presta valve.

In general, most small adaptors, extenders, and adjustable
devices fail to work as well as the real things whose
specific purpose they are meant to imitate.

Carl Fogel

 

[Chuck Davis]

<[email protected]> wrote in message
news:[email protected]...
> .....
> As for valve extenders, I found them so annoying that I
> switched to long valve stems after fooling around with
> teflon tape to seal the threads.
>
> Another problem is that the extender is just a hollow shell
> that fits down over the real Presta valve, whose lock-nut
> must be left unscrewed, leaving nothing but air-pressure to
> seal the valve.
>
> In addition to the obvious problem of losing air-pressure
> without a lock-nut, the extender makes it hard to break a
> stuck valve free.
>
> This can cause two problems. First, you can't pump the tube
> any further if the valve sticks on a mostly-filled tube.
> Second, you can't let the air out to collapse a slow-leak
> flat to remove the tire.
>
> So you have to remove and replace the extender, an awkward
> job, or else carry something to poke down into it to free
> the hidden Presta valve.
>
> In general, most small adaptors, extenders, and adjustable
> devices fail to work as well as the real things whose
> specific purpose they are meant to imitate.
>
> Carl Fogel
>

If you use an extender such as:

http://www.worldclasscycles.com/valve_extension_tube.htm

you'll find that they have a valve control that allows you to open and close
the valve. The metal extenders do need an O-ring or Teflon tape for a good
seal on the valve, but plastic versions of this type of extender will seal
as is.

Chuck Davis

 

[Paul Kopit]

On Sun, 12 Sep 2004 13:44:10 -0400, "psycholist" <[email protected]>
wrote:

>If you've ever used a valve extender, you know that you sometimes have to
>screw them on pretty tightly to avoid having more of the air you pump in
>exit via the threads instead of going into the tube. It can be a real trick
>to screw them on tight enough for inflation, but loose enough that they can
>be removed without coring the valve.

If you put some teflon tape on the valve stem, the extenders work
fine. You can also put a piece of teflon into your patch kit.

 

[Mark]

[email protected] (Paul Nevai) wrote in message news:<[email protected]>...
> Another day, another surprise. I found out that the presta valve on one of my
> tubes screws out. In fact, it screws out and the tube loses pressure
> appr. one out of ten times when I screw of the little plastic valve cap from
> it. I never knew that those cores can be screwed out and it appears that on
> all but one of my tubes it can't be screwed out, and are in fact not even
> separate pieces but are part of the valve stem.
>
> Let me try to specify. It's not the "core" what screws out but the thing
> which holds the core and which itself is screwed into the valve stem.
>
> So when this thingie can be screwed out, is this a "lower" or "higher"
> quality indicator.
>
> Also, how can I screw it in so it would never ever screw out again, I tried
> to wrap a rubber piece around it and then use a wise grip plier but I am not
> sure it worked.
>
> Thanks, Paul

Hi Paul, Were these tubes that have "slime" (Flat sealer) already
applies to them? I know with these type tubes they generally have to
have a means to be able to insert the sealer compound, and therefore,
the Presta Valve screws apart to do this. perhaps to prevent them
from coming apart ever again, apply some Loctite thread locking
compound on the threads, and let it dry for a good 42 hours before
refilling with air, and using. Mark

 

[[email protected]]

On Sun, 12 Sep 2004 16:59:30 -0400, "Chuck Davis"
<[email protected]> wrote:

>
><[email protected]> wrote in message
>news:[email protected]...
>> .....
>> As for valve extenders, I found them so annoying that I
>> switched to long valve stems after fooling around with
>> teflon tape to seal the threads.
>>
>> Another problem is that the extender is just a hollow shell
>> that fits down over the real Presta valve, whose lock-nut
>> must be left unscrewed, leaving nothing but air-pressure to
>> seal the valve.
>>
>> In addition to the obvious problem of losing air-pressure
>> without a lock-nut, the extender makes it hard to break a
>> stuck valve free.
>>
>> This can cause two problems. First, you can't pump the tube
>> any further if the valve sticks on a mostly-filled tube.
>> Second, you can't let the air out to collapse a slow-leak
>> flat to remove the tire.
>>
>> So you have to remove and replace the extender, an awkward
>> job, or else carry something to poke down into it to free
>> the hidden Presta valve.
>>
>> In general, most small adaptors, extenders, and adjustable
>> devices fail to work as well as the real things whose
>> specific purpose they are meant to imitate.
>>
>> Carl Fogel
>>
>
>If you use an extender such as:
>
>http://www.worldclasscycles.com/valve_extension_tube.htm
>
>you'll find that they have a valve control that allows you to open and close
>the valve. The metal extenders do need an O-ring or Teflon tape for a good
>seal on the valve, but plastic versions of this type of extender will seal
>as is.
>
>Chuck Davis
>

Dear Chuck,

Assuming that they work, those valve extenders add a nice
feature, but at $26 plus shipping for a pair of 50 mm
extenders, I'd be looking for tubulars with long stems if I
used tubulars.

If you know where to find the easier-sealing plastic version
of these valve-extenders with valve-controls, I imagine that
some tubular enthusiasts reading this thread would be
pleased to see the link.

Carl Fogel

 

[david]

Tufo tubulars don't come with long valves. They have the removal valve nut,
and you remove that, put their extender in there via screwing in using the
valve threads on the inside of the tube valve and screw the presta valve
insert into the top of the extension. works marvelously - no teflon tape
required.

david

 

[Chuck Davis]

<[email protected]> wrote in message
news:[email protected]...
> On Sun, 12 Sep 2004 16:59:30 -0400, "Chuck Davis"
> <[email protected]> wrote:
> ........
>>If you use an extender such as:
>>
>>http://www.worldclasscycles.com/valve_extension_tube.htm
>>
>>you'll find that they have a valve control that allows you to open and
>>close
>>the valve. The metal extenders do need an O-ring or Teflon tape for a
>>good
>>seal on the valve, but plastic versions of this type of extender will seal
>>as is.
>>
>>Chuck Davis
>>
>
> Dear Chuck,
>
> Assuming that they work, those valve extenders add a nice
> feature, but at $26 plus shipping for a pair of 50 mm
> extenders, I'd be looking for tubulars with long stems if I
> used tubulars.
>
> If you know where to find the easier-sealing plastic version
> of these valve-extenders with valve-controls, I imagine that
> some tubular enthusiasts reading this thread would be
> pleased to see the link.
>
> Carl Fogel

Carl,

You can find the plastic version on one of my rear wheels. The only link
pointing to it is part of my chain. 8) I bought the extender in 1997 when
I bought a Spinergy wheel. I looked for plastic extenders again lately and
was only able to find metal extenders (with the core I mentioned.) Yes, they
do work and they work quite well. I found them at Nashbar for $9 each, but
they're not listed there anymore.

I ran across this interesting tip at
http://www.bookcase.com/faq/bicycles-faq/part3:

"Another tip.For those with deep dish rims requiring valve extenders, place
a small amount of loctite on the tube valve stem threads and then screw the
valve extender on. This will prevent any leaking at that junction once the
tire is glued on."

As I think about it, it seems that a little Loctite on each valve would be
enough to get a seal for each tire or tube that you have. If you want to
save money, you could get ONE metal extender with the core and a plastic one
without. Use the plastic one to inflate the tire and use the metal one to
close the valve. In that case, you won't need any seal for the metal
extender.

Chuck Davis

 

[Paul Nevai]

[email protected] (Mark) aszonygya:
:Hi Paul, Were these tubes that have "slime" (Flat sealer) already
:applies to them? I know with these type tubes they generally have to
:have a means to be able to insert the sealer compound, and therefore,
:the Presta Valve screws apart to do this. perhaps to prevent them
:from coming apart ever again, apply some Loctite thread locking
:compound on the threads, and let it dry for a good 42 hours before
:refilling with air, and using. Mark

Nope. Plain vanilla 700 mm 19-25 mm tubes. Loctite? Great idea. I happen to
have a small tube of it. Best regards, Paul

 

[Werehatrack]

On 12 Sep 2004 13:44:43 GMT, [email protected] (Paul Nevai) wrote:

>So when this thingie can be screwed out, is this a "lower" or "higher"
>quality indicator.

It's a difference, and some people like and/or need them, but unless
you have a use for the feature, it's not an advantage.

>Also, how can I screw it in so it would never ever screw out again, I tried
>to wrap a rubber piece around it and then use a wise grip plier but I am not
>sure it worked.

I'd just put a drop of Loctite on it.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

 

[[email protected]]

On Sun, 12 Sep 2004 20:48:36 -0400, "Chuck Davis"
<[email protected]> wrote:

>
><[email protected]> wrote in message
>news:[email protected]...
>> On Sun, 12 Sep 2004 16:59:30 -0400, "Chuck Davis"
>> <[email protected]> wrote:
>> ........
>>>If you use an extender such as:
>>>
>>>http://www.worldclasscycles.com/valve_extension_tube.htm
>>>
>>>you'll find that they have a valve control that allows you to open and
>>>close
>>>the valve. The metal extenders do need an O-ring or Teflon tape for a
>>>good
>>>seal on the valve, but plastic versions of this type of extender will seal
>>>as is.
>>>
>>>Chuck Davis
>>>
>>
>> Dear Chuck,
>>
>> Assuming that they work, those valve extenders add a nice
>> feature, but at $26 plus shipping for a pair of 50 mm
>> extenders, I'd be looking for tubulars with long stems if I
>> used tubulars.
>>
>> If you know where to find the easier-sealing plastic version
>> of these valve-extenders with valve-controls, I imagine that
>> some tubular enthusiasts reading this thread would be
>> pleased to see the link.
>>
>> Carl Fogel
>
>Carl,
>
>You can find the plastic version on one of my rear wheels. The only link
>pointing to it is part of my chain. 8) I bought the extender in 1997 when
>I bought a Spinergy wheel. I looked for plastic extenders again lately and
>was only able to find metal extenders (with the core I mentioned.) Yes, they
>do work and they work quite well. I found them at Nashbar for $9 each, but
>they're not listed there anymore.
>
>I ran across this interesting tip at
>http://www.bookcase.com/faq/bicycles-faq/part3:
>
>"Another tip.For those with deep dish rims requiring valve extenders, place
>a small amount of loctite on the tube valve stem threads and then screw the
>valve extender on. This will prevent any leaking at that junction once the
>tire is glued on."
>
>As I think about it, it seems that a little Loctite on each valve would be
>enough to get a seal for each tire or tube that you have. If you want to
>save money, you could get ONE metal extender with the core and a plastic one
>without. Use the plastic one to inflate the tire and use the metal one to
>close the valve. In that case, you won't need any seal for the metal
>extender.
>
>Chuck Davis

Dear Chuck,

This is probably not the best time to mention that I have
for years harvested nice metal Schrader valve caps with the
built-in valve-core wrench from a friend's motorcycle, often
right in front of him when we're checking motorcycle tire
pressures with the machines on the trailer. (The caps come
off quit easily and look much better on my tubes than on
his.)

Let's hope that no one admires your 1997 plastic extenders
enough to follow my evil example.

Carl Fogel