presta valve core failures

In article ,
Mark Hickey wrote:

"Llatikcuf" wrote:

Mark Heiple wrote:

So far my score for flats is:

Running over something pointy: 0
Spokes puncturing from the inside: 1
Valve stem tearing: 2 or 3
Valve cores failing: too many to count

Any suggestions for a reliable tube?

Wow! I've never had a valve fail and I don't buy new tubes, I just
patch and reuse the old ones other people leave on the side of the road
-- pet peeve of mine. Some of my tubes are 5 years old now.

You don't oil the valve cores do you?

That's likely, I think... he's gotta be doing SOMETHING different than
I am. I've gone through hundreds of tubes over the years, and can't
remember more than one or two valve cores failing (if that...).

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

No oil. I use a Blackburn floor pump, but that can't have anything to do
with it.

In article ,
Jeff Starr wrote:

On Thu, 03 Nov 2005 04:40:14 GMT, "Ricardo"
wrote:

Now we are getting down to it. Why is it that the most complicated part of
bike maintained is blowing up the damn tires. I bought a cheap floor pump,
hassles, bought an expensive floor pump, hassles. I mean I have this 70
dollar pump and I have to hold the coupling on with one hand and pump with
the other, otherwise bend that little thingy. Put it in too far, don't put
it in enough. Jesus, I have a wife who will give me a commentary on that.
What I do in the privacy of my own garage, how do you keep a valve stem
happy? Ricardo

I don't understand, do you and the OP have problems with all things
mechanical?


Where did I say I have a problem with all things mechanical, or didn't
know how to inflate a tire?

I check and when necessary, which is every few days, pump up my tires.
It takes, maybe two minutes.

I use a Topeak digital gauge to accurately test pressure.
http://www.campmor.com/webapp/wcs/st...memberId=12500
226&productId=30373072


Although the nut that comes with threaded presta valve stems isn't
necessary and shouldn't be tightened down, I do use them. Before
putting the pump or gauge on, I thread it down to the rim. When done,
I snug it against the valve cap. By having it up against the rim, I
can push straight down, without fear of doing any damage, by pushing
the valve inward.


I don't use the nut at all. I have never needed it, it doesn't do
anything useful.


I use a Topeak Joe Blow Sport Pump, it has two heads, push on, turn
lever 90 degrees, and pump.
http://www.campmor.com/webapp/wcs/st...memberId=12500
226&productId=39158834

The o-ring in the lever, will wear out, on the two sided pump head.
Although I found it easy to replace, I upgraded the head to Topeak's
Smarthead. Put it on, pull up lever and pump. Very simple.
http://www.performancebike.com/shop/...tegory_ID=4363

The Smarthead hose kit, should work on most brands of pump.


I use a blackburn floor pump.

I have yet to have a valve stem fail. I have over 8000 miles on my
current bike, which gets the tires checked regularly.


Congratulations.

Maintaining your tires is really very simple.



Thanks.

Life is Good!
Jeff

"Mark Heiple" wrote in message
...
In article ,
"CEarly" wrote:

"Mark Heiple" wrote in message
...
I've been having problems with the presta valve cores failing. Usually
the bike is just sitting home when it happens. Sometimes the tire goes
flat sitting over night, sometimes it goes right after pumping up the
tire. A couple times the rubber at the base of the stem tears, but
usually it is the valve itself. I've checked by putting a little air
in
and holding it under water and watch the bubbles.

I used to use Continental tubes, which have a removable core. All of
them have eventually failed, usually lasting about 1 year. My last one
failed a couple days ago.

I got 2 Trek/Bontrager tubes (with removable cores). The first I tried
was bad out of the box, the 2nd was ok.

I have 2 Salsa tubes, which don't have removable cores, they have been
ok so far. one has been on the bike since about early spring, the other
is still in the box.

So far my score for flats is:

Running over something pointy: 0
Spokes puncturing from the inside: 1
Valve stem tearing: 2 or 3
Valve cores failing: too many to count

Any suggestions for a reliable tube?

Thanks.


What do you see when you remove the cores? Is the little plastic seat
broken? I've had tubes with removable cores leak at the valve, but it
has
usually been due to the core being a bit loose - easily fixed by
tightening
it slightly. Occasionally, I've had the valve seat crack and then the
core
is junk.

Cal

I haven't seen anything that looked obviously broken. I've tried
tightening the cores, but they seem to never hold air again. I'll pump
up the tire, it will hold for a few minutes, then go flat again.


Take out one of these failed cores and look at the beveled ring of white
plastic on it. That's what seals. You'll probably see that it is cracked.
If you tighten the core too much in the stem, it seems to crack the seal on
the core. This may be what is causing your leaks. I had the same problem
and found that if I replace a core that had a cracked seal with one that
didn't the leak stopped.

Cal

"Ricardo" wrote:

Now we are getting down to it. Why is it that the most complicated part of
bike maintained is blowing up the damn tires. I bought a cheap floor pump,
hassles, bought an expensive floor pump, hassles. I mean I have this 70
dollar pump and I have to hold the coupling on with one hand and pump with
the other, otherwise bend that little thingy. Put it in too far, don't put
it in enough. Jesus, I have a wife who will give me a commentary on that.
What I do in the privacy of my own garage, how do you keep a valve stem
happy? Ricardo

I've been pestered by that issue myownself... I finally replaced all
the heads on my floor pumps with the Topeak "SmartHead" (fills both
Presta and Shraeder valves without changing anything). Never leaks,
never slips, works perfectly every time. MUCH better than anything
from Campy or Silca, IMHO.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

Mark Heiple wrote:


Most of the failures have been with the valve core. I had a couple
stems tear at the base, but I started putting an extra piece of Velox
over the stem, and I haven't had that problem since.

When the core fails, it seems like the core isn't making an air tight
seal, maybe it unscrews a little. I've tried tightening it, but it has
never helped. Once it starts leaking, it won't hold air any more. I
will pump the tire up to 120 psi, it will hold for a few minutes, but
then it all leaks out again.

Do you remove the cores or do they just go bad leaving them as you got
them from the factory? Perhaps it's in the handling while out or in the
reinsertion where your trouble lies.

Mark Heiple wrote:
When the core fails, it seems like the core isn't making an air tight
seal, maybe it unscrews a little. I've tried tightening it, but it has
never helped. Once it starts leaking, it won't hold air any more. I
will pump the tire up to 120 psi, it will hold for a few minutes, but
then it all leaks out again.

I don't mean to insult your intelligence, but are you sure that the
valve core is the problem? When I have leaks anywhere in the tube, it
usually seems like the air is coming from the stem area because that's
the easiest place for the air to escape the tire/rim cavity.

The only way to really find the leak is with the tube out of the tire.

--
Dave
dvt at psu dot edu

In article , dvt
wrote:

Mark Heiple wrote:
When the core fails, it seems like the core isn't making an air tight
seal, maybe it unscrews a little. I've tried tightening it, but it has
never helped. Once it starts leaking, it won't hold air any more. I
will pump the tire up to 120 psi, it will hold for a few minutes, but
then it all leaks out again.

I don't mean to insult your intelligence, but are you sure that the
valve core is the problem? When I have leaks anywhere in the tube, it
usually seems like the air is coming from the stem area because that's
the easiest place for the air to escape the tire/rim cavity.

The only way to really find the leak is with the tube out of the tire.

I checked the first few by taking them out of the tire and holding under
water. The bubbles always came out the valve. After the first few, I
quit checking.

I don't think they were punctures in the tube, because it never happened
during a ride. It would go flat just sitting at home.

In article ,
Paul Cassel wrote:

Mark Heiple wrote:


Most of the failures have been with the valve core. I had a couple
stems tear at the base, but I started putting an extra piece of Velox
over the stem, and I haven't had that problem since.

When the core fails, it seems like the core isn't making an air tight
seal, maybe it unscrews a little. I've tried tightening it, but it has
never helped. Once it starts leaking, it won't hold air any more. I
will pump the tire up to 120 psi, it will hold for a few minutes, but
then it all leaks out again.

Do you remove the cores or do they just go bad leaving them as you got
them from the factory? Perhaps it's in the handling while out or in the
reinsertion where your trouble lies.

I don't do anything with the core, I just put it on and pump it up.

I replaced my last bad tube with a trek/bontrager tube (I have 2). The
core of the 1st one fell out of the stem as I was taking it out of the
wrapper. The 2nd seems to be ok. I suppose I should screw the core
back into the 1st and see if holds air, but given my luck, I don't
really trust it.

Mark Heiple wrote:

I checked the first few by taking them out of the tire and holding under
water. The bubbles always came out the valve. After the first few, I
quit checking.

I don't think they were punctures in the tube, because it never happened
during a ride. It would go flat just sitting at home.

Mark,

Again, please don't take offense because I don't wish to offer any, but
you are the only person who seems to have this problem. That implies
very strongly that there is something different about your behavior or
equipment. For example, you say it can't be your pump. Then what can it
be? Aside from pump, it must be something you are doing.

I can't figure any other factor. I and many here use Conti tubes
exclusively. While I'm hardly an old timer on bikes, I've been though
enough tubes to say that there are no core issues at all with them. My
LBS sells hundreds of them w/o a core failure (I asked).

I think you need to examine your fill technique and your pump.

-paul

In article ,
Paul Cassel wrote:

Mark Heiple wrote:

I checked the first few by taking them out of the tire and holding under
water. The bubbles always came out the valve. After the first few, I
quit checking.

I don't think they were punctures in the tube, because it never happened
during a ride. It would go flat just sitting at home.

Mark,

Again, please don't take offense because I don't wish to offer any, but
you are the only person who seems to have this problem. That implies
very strongly that there is something different about your behavior or
equipment. For example, you say it can't be your pump. Then what can it
be? Aside from pump, it must be something you are doing.

I can't figure any other factor. I and many here use Conti tubes
exclusively. While I'm hardly an old timer on bikes, I've been though
enough tubes to say that there are no core issues at all with them. My
LBS sells hundreds of them w/o a core failure (I asked).

I think you need to examine your fill technique and your pump.

-paul

No offense taken, I appreciate constructive advice and criticism.

Been thinking about what I might be doing different. I do try to keep my
tire pressure up, so I usually top them off every few days, usually not
more than a week. Judging from what I've read here in the past, that
probably isn't putting excessive wear and tear on the valve.

I have been leaving the valve cap off. Some guys I know use the cap all
the time, others just throw it away and never use it. I'll use it and
see if that makes a difference. Maybe something gets in valve and
corrodes it, although I thought the cap didn't provide a good enough
seal to do any good.

My other thought was maybe when I screw the valve nut down, I am using
too much force. I have just been making it snug, but maybe I am trying
to tighten it too much and breaking it.