Presta valve stems keep blowing

Newsgroups said:

I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the
threaded metal sleeve.

Question:

Am I inserting the valve stem incorrectly? I try to align the stem perfectly centered and
perpendicular to the rim.

Also, I asked my lbs how tight to turn the ring over the stem threads, and they said "not tight at
all: leave it a little loose".

Am I missing something here, or am I just unlucky with blowouts at that spot?

I've had a couple such failures recently (none ever before). Both were with relatively old inner
tubes (a few years old).

For the ring, I think it should be tight enough to limit the movement of the valve, but not so tight
that it pulls too hard against the rim. The other thing to try to avoid is damaging the inner tube
when you're putting it on the rim.

A bientot Paul
--
Paul Floyd paulf.free.frpaulf.free.frOpen ↗ (for what it's worth) Surgery: ennobled Gerald.

<< I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the
threaded metal sleeve. Question: Am I inserting the valve stem incorrectly? I try to align the stem
perfectly centered and perpendicular to the rim. Also, I asked my lbs how tight to turn the ring
over the stem threads, and they said "not tight at all: leave it a little loose". >>

Check the valve hole in the rim for burrs or sharp edges, If necessary, smooth it down with emery
cloth. Then, make sure this area is protected by the rim strip. Don't use the threaded collar for
the valve stem. It serves no purpose. Instead, use your thumb when you press the pump head onto the
valve to keep from pushing it up into the tire.

Newsgroups said:

I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the
threaded metal sleeve.

Question:

Am I inserting the valve stem incorrectly? I try to align the stem perfectly centered and
perpendicular to the rim.

Also, I asked my lbs how tight to turn the ring over the stem threads, and they said "not tight at
all: leave it a little loose".

Am I missing something here, or am I just unlucky with blowouts at that spot?

Throw the little thread on ring away. It serves no purpose other than to damage your tube.

Most of the failures that I've seen of valve stems occur when big strong guys pump up a recently
repaired tyre on the road. Many people naturally look for something to brace the wheel against, so
they can push nice and hard on the pump. This causes the pump head to put a lot of sideward pressure
on the stem, which then fails.

When I pump up my tyres on the road (at home I use a track pump, with a hose to the valve) I do so
with the wheel off the bike. I hold the wheel up in the air a little bit, and hold the pump head
with one hand, and the handle with the other. The wheel is totally unsupported. This way, I'm not
forcing the stem into any weird angles. As a result, I've never had a valve stem fail.

Regards,

Suzy

Quoted message said:

I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the
threaded metal sleeve. Question: Am I inserting the valve stem incorrectly? I try to align the stem
perfectly centered and perpendicular to the rim.

Maybe your straining the tube/valve connection when you remove your pump chuck. A lot of people
twist and turn it to remove. I've had the best luck popping it straight off with a thumb on either
side. Steve

Newsgroups said:

I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the
threaded metal sleeve.

Question:

Am I inserting the valve stem incorrectly? I try to align the stem perfectly centered and
perpendicular to the rim.

Also, I asked my lbs how tight to turn the ring over the stem threads, and they said "not tight at
all: leave it a little loose".

Am I missing something here, or am I just unlucky with blowouts at that spot?

I'm assuming that the valve is tearing out, not that you're getting a hole at the valve from a rim
with a sharp spot.

Some brands of tubes are more prone to it than others. Switch inner tube brands.

I snug the nut lightly. It helps hold the valve when you're putting the tire on and when you're
attaching the pump. Once the tire's up to pressure, you could remove it if you were worried about
it. But I doubt that's your problem.

The other thing to consider is when using a compact frame pump. I put my hand around the pump head
and the spoke next to the valve so that when I pump, I put pressure on the spoke, not the valve.

David

"Newsgroups" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the
threaded metal sleeve.

Question:

Am I inserting the valve stem incorrectly? I try to align the stem perfectly centered and
perpendicular to the rim.

Also, I asked my lbs how tight to turn the ring over the stem threads, and they said "not tight at
all: leave it a little loose".

Am I missing something here, or am I just unlucky with blowouts at that spot?

My bet is that you have a bad batch of tubes, unless they're different brands. If they're the same
brand & lot, try something else, and throw those silly rings away.

howard wrote:

<< I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the
threaded metal sleeve. >>

I bet ten bucks you tear the stem away from the tube from overzealous pumping technique.

The question of how tight to tighten the nut is interesting. I believe that overtightening the nut
makes it easier for the stem to tear away, but leaving it loose is not good either. I say tighten it
very modestly.

If not bad pumping, a bad batch of tubes.

Robert

Thanks all for your help.

I get two schools of thought on the ring that holds the stem to the rim:
A) Throw it away
B) Tighten it just enough to hold the stem against the rim, but not too tight

I wonder how there could be such diametrically opposed views. Somebody's gotta be right, no?

I like this thought: "I bet ten bucks you tear the stem away from the tube from overzealous pumping
technique."

That has the ring of truth to it.

Thanks again

Howard Levinger

"Newsgroups" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the
threaded metal sleeve.

Question:

Am I inserting the valve stem incorrectly? I try to align the stem perfectly centered and
perpendicular to the rim.

Also, I asked my lbs how tight to turn the ring over the stem threads, and they said "not tight at
all: leave it a little loose".

Am I missing something here, or am I just unlucky with blowouts at that spot?

TIA

Howard

Peter Cole said:

My bet is that you have a bad batch of tubes, unless they're different brands. If they're the same
brand & lot, try something else, and throw those silly rings away.

I'm for that analysis. I find odd that people ask this question here often and always seem to
believe it is their own fault when in fact it is a manufacturing flaw. Take the tubes back to the
store and demand replacements.

There are always smarty responses that place the blame with the use of knurled stem retaining nuts
that come with the tube. Considering that the manufacturer offers these as useful attachments and
how many thousands of tubes, with jam nuts. have served many thousands of miles, this suggestion is
preposterous. Beyond that, I suggest those who believe this story, apply a jam nut to a stem when
the tire is completely flat, pump the tire to the usual pressure and see where the lock nut is. It
will be about 2-3mm away from the rim. 100psi does more to extend the stem than you can reasonably
do with your fingers.

Jobst Brandt [email hidden]

"Newsgroups" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the
threaded metal sleeve.

Question:

Am I inserting the valve stem incorrectly? I try to align the stem perfectly centered and
perpendicular to the rim.

Also, I asked my lbs how tight to turn the ring over the stem threads, and they said "not tight at
all: leave it a little loose".

Am I missing something here, or am I just unlucky with blowouts at that spot?

TIA

Howard

Are your rims drilled for schrader valves?

Newsgroups said:

I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the
threaded metal sleeve.

Question:

Am I inserting the valve stem incorrectly? I try to align the stem perfectly centered and
perpendicular to the rim.

Also, I asked my lbs how tight to turn the ring over the stem threads, and they said "not tight at
all: leave it a little loose".

Am I missing something here, or am I just unlucky with blowouts at that spot?

Why do you add the outer lockring? We don't, as we see no useful purpose.
--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

In article <[email hidden]>, "Newsgroups"

Quoted message said:

I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the
threaded metal sleeve.

Are you a mountain biker? I have had a valve stem tear off because the tire shifted on the rim while
braking heavily on steep,rocky descents.

Presumably the wheel loses contact with the ground when going over a rock, the wheel immediately
locks up, and recontacting the ground provides an impulse that shifts the tire. Very often after a
steep descent I notice that the tire has shifted a bit, and the valve stem is now at a slant with
respect to the rim. I then unmount and remount the tire.The cures suggested in this newsgroup were
checking air pressure (I had 60 psi), checking that the rim and tire hadn't been treated with some
sort of silicone stuff for easy mounting (mine weren't), and gluing the tire to the rim (haven't
tried this yet).

--
Ned Mantei Department of Cell Biology, Swiss Federal Institute of Technology CH-8093 Zurich,
Switzerland

A Muzi said:

Why do you add the outer lockring? We don't, as we see no useful purpose.

I don't know why the OP does it, but with shorter stems, I find that they disappear before I can get
the pump head on them, no matter how I try to hold.

--
Rick Onanian

Quoted message said:

I'm for that analysis. I find odd that people ask this question here often and always seem to
believe it is their own fault when in fact it is a manufacturing flaw. Take the tubes back to the
store and demand replacements.

While it's most likely usually a manufacturing defect, presta valves do seem to be more
breakage-prone. I've never had a schraeder valve break, nor have I seen it happen. I have had a
presta valve break; and I rode with a group where a rider got a flat; broke the valve while
attempting to inflate; was given a tube by another rider; that valve broke; given another tube from
yet a different rider, and finally was able to inflate.

It was probably the overzealous pumping action which was suggested by somebody else in this thread;
but schraeder valves are robust enough to survive that, while one must excersize care with a presta
valve. As such, it's not unreasonable that it could be somebody's actions, rather than manufacturing
defects, that caused a string of valve stem blows.

Quoted message said:

Jobst Brandt [email hidden]

--
Rick "Still kinda likes presta anyway" Onanian

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Content-Transfer-Encoding: 7bit

Howard:

I'm from the "A" school. Why? Because you really don't want the stem against the rim! You want the
tube to be seated WITHIN the tire all the way around the tire - the stem is only how you get the air
into the tire. What you really want to do is to start inflating the tire with the stem pushed into
the tire, not pulled out against the rim. After you have 30 lbs or so of air in the tire you no
longer have to push the valve in as the air pressure will hold the tube in place.

MOO, Matt

Howard said:

Thanks all for your help.

I get two schools of thought on the ring that holds the stem to the rim:
A) Throw it away
B) Tighten it just enough to hold the stem against the rim, but not too tight

I wonder how there could be such diametrically opposed views. Somebody's gotta be right, no?

I like this thought: "I bet ten bucks you tear the stem away from the tube from overzealous pumping
technique."

That has the ring of truth to it.

Thanks again

Howard Levinger

"Newsgroups" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to the
threaded metal sleeve.

Question:

Am I inserting the valve stem incorrectly? I try to align the stem perfectly centered and
perpendicular to the rim.

Also, I asked my lbs how tight to turn the ring over the stem threads, and they said "not tight at
all: leave it a little loose".

Am I missing something here, or am I just unlucky with blowouts at that spot?

TIA

Howard

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Content-Transfer-Encoding: 7bit

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title></title>
</head> <body> Howard:<br> <br> I'm from the "A" school. Why? Because you really don't
want the stem against the rim! You want the tube to be seated WITHIN the tire all the way
around the tire - the stem is only how you get the air into the tire. What you really want to
do is to start inflating the tire with the stem pushed into the tire, not pulled out against the
rim. After you have 30 lbs or so of air in the tire you no longer have to push the valve in as
the air pressure will hold the tube in place. <br> <br> MOO,<br> Matt<br> <br> Howard
wrote:<br> <blockquote type="cite" cite="[email hidden]">
<pre wrap="">Thanks all for your help.

I get two schools of thought on the ring that holds the stem to the rim:
A) Throw it away
B) Tighten it just enough to hold the stem against the rim, but not too tight

I wonder how there could be such diametrically opposed views. Somebody's gotta be right, no?

I like this thought: "I bet ten bucks you tear the stem away from the tube from overzealous pumping
technique."

That has the ring of truth to it.

Thanks again

Howard Levinger

"Newsgroups" <a class="moz-txt-link-rfc2396E"
href=""][email hidden]"><[email hidden]></a> wrote in message <a
class="moz-txt-link-freetext" href=""]news:[email hidden]">news-
:[email hidden]</a>... </pre> <blockquote type="cite"> <pre
wrap="">I keep getting holes at the juncture of the tube and the perpendicular rubber attachment to
the threaded metal sleeve.

Question:

Am I inserting the valve stem incorrectly? I try to align the stem perfectly centered and
perpendicular to the rim.

Also, I asked my lbs how tight to turn the ring over the stem threads, and they said "not tight at
all: leave it a little loose".

Am I missing something here, or am I just unlucky with blowouts at that spot?

TIA

Howard

</pre> </blockquote> <pre wrap=""><!---->

</pre> </blockquote> <br> </body> </html>

--------------000100020209070903010807--

Quoted message said:

miles, this suggestion is preposterous. Beyond that, I suggest those who believe this story, apply
a jam nut to a stem when the tire is completely flat, pump the tire to the usual pressure and see
where the lock nut is. It will be about 2-3mm away from the rim. 100psi does more to extend the
stem than you can reasonably do with your fingers.

Some people then continue to do up the nut, of course.
--
David Damerell <[email hidden]> Distortion Field!

A Muzi <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Why do you add the outer lockring? We don't, as we see no useful purpose.

Hi, when I switched wheels and they had presta valves, my LBS mechanic told me that he didn't use
the rings. His reason was that people keep tightening them until they do damage. That was good
enough for me, but I have found a need for the ring. I have one tire that when I try to top off
the pressure, the pump nozzle wouldn't engage properly. The pump is a Joe Blow Sport with the two
sided nozzle. It works fine on the three other presta valves, consistently, so I thnk it's the
valve, not the pump.

Anyway, to get the pump to work, I have to press down, very hard, to get it on far enough to
catch[?]. I was afraid I would wreck the tube, doing this, so I put the nut on and run it down to
the rim, before filling. When I am done, I put the cap on and then back the nut off, so it is
against the cap. So, in this case, it has a useful purpose.

Some one else mentioned that they use them when mounting the tube and tire, that sounds like a good
idea. In the past, I've had a few Schraeder valves, end up crooked, it seem that the temporary use
of the presta nut would prevent this. Life is Good! Jeff

Quoted message said:

Why do you add the outer lockring? We don't, as we see no useful purpose.
--

Not on the tube but , oh boy, are they useful for other things, like spacing toe clips, for
instance. Phil Brown

"Jeff Starr" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Anyway, to get the pump to work, I have to press down, very hard, to get it on far enough to
catch[?]. I was afraid I would wreck the tube, doing this, so I put the nut on and run it down to
the rim, before filling.

I'd be more worried about ruining the pump. The rubber grommet that seals against the valve gets
all torn up when you force the head on the valve, lose the bad tube, or unscrew the cap on the pump
head a bit.

Quoted message said:

When I am done, I put the cap on and then back the nut off, so it is against the cap. So, in this
case, it has a useful purpose.

No, just throw those away too.