Strange tube failure

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

Quoted message said:

These 23-28 Kenda tubes came with some wheels and 32mm tires I bought
cheap, the tubes seemed a little small but I don't know if that is what
caused this problem:

http://homepage.mac.com/getosx/puncture.jpg

I'd ridden these tires/tubes 100 miles or so, last ride was on Saturday,
they held air fine until tonight when the front was totally flat. The hole
is the chevron shaped marks to the right of the stem. There are no sharp
edges around the stem hole.

Is this a manufacturing defect? You can make out the beginnings of
similar marks to the left of the stem.

You're not the only one. I've had flats come into the shop with similar
problems, many of them with failures next to the valve stem, and not
obviously on the edge of the bond between thin and thick rubber. Maybe a
little closer to the valve stem.

I've also seen some tubes come out with almost-herniating "thin spots" right
where your chevrons are... looking like they're about to fail.

They seem unrelated to the valve hole or rim strip.

--
Phil, Squid-in-Training

Greg T? said:

These 23-28 Kenda tubes came with some wheels and 32mm tires I
bought cheap, the tubes seemed a little small but I don't know if
that is what caused this problem:

http://homepage.mac.com/getosx/puncture.jpg

Quoted message said:

I'd ridden these tires/tubes 100 miles or so, last ride was on
Saturday, they held air fine until tonight when the front was
totally flat. The hole is the chevron shaped marks to the right of
the stem. There are no sharp edges around the stem hole.

Quoted message said:

Is this a manufacturing defect? You can make out the beginnings of
similar marks to the left of the stem.

That looks like a tool mark from mounting although I can't imagine
what brought it there. It occurred on or before mounting the tire and
broke through some time near the end of the ride... or was slowly
leaking all the time. Had you re-inflated the tire, we would know
more about the leak rate. As it is, patch the tube and be done with
it. You might inspect the other tubes from that lot that you have for
similar marks, but I doubt you'll find any.

Jobst Brandt

G.T. said:

These 23-28 Kenda tubes came with some wheels and 32mm tires I bought
cheap, the tubes seemed a little small but I don't know if that is what
caused this problem:

http://homepage.mac.com/getosx/puncture.jpg

I've seen lots of these .. mostly on cheap tubes.. never knew why they
occured and even though I tried very hard to figue it out, I still
don't. but I've seen lots..

On Wed, 08 Mar 2006 23:26:53 -0800, "G.T." <[email hidden]>

Quoted message said:

These 23-28 Kenda tubes came with some wheels and 32mm tires I bought
cheap, the tubes seemed a little small but I don't know if that is what
caused this problem:

http://homepage.mac.com/getosx/puncture.jpg

I'd ridden these tires/tubes 100 miles or so, last ride was on Saturday,
they held air fine until tonight when the front was totally flat.
The hole is the chevron shaped marks to the right of the stem. There
are no sharp edges around the stem hole.

Is this a manufacturing defect? You can make out the beginnings of
similar marks to the left of the stem.

I tend to see this on tubes whose stem area is thick and heavy; I've
also noticed that the stems on these don't fully rise from the hole in
the rim for as much as 15 to 20 minutes after the tire is inflated.
I've been able to reduce such failures to near zero by inflating the
tire twice (or more) so that I get an immediate full rise of the stem
through the valve hole. I think that what's going on is that the
heavy flange at the base of the stem is bridging the channel between
the flanges, leaving a void into which the tube's thinner area next to
the flange then bubbles out and bursts.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Quoted message said:

Greg T? said:

These 23-28 Kenda tubes came with some wheels and 32mm tires I
bought cheap, the tubes seemed a little small but I don't know if
that is what caused this problem:

http://homepage.mac.com/getosx/puncture.jpg

Quoted message said:

I'd ridden these tires/tubes 100 miles or so, last ride was on
Saturday, they held air fine until tonight when the front was
totally flat. The hole is the chevron shaped marks to the right of
the stem. There are no sharp edges around the stem hole.

Quoted message said:

Is this a manufacturing defect? You can make out the beginnings of
similar marks to the left of the stem.

That looks like a tool mark from mounting although I can't imagine
what brought it there.

I wish I had thought of inspecting the tubes when I received them.

Quoted message said:

It occurred on or before mounting the tire and
broke through some time near the end of the ride... or was slowly
leaking all the time. Had you re-inflated the tire, we would know
more about the leak rate.

I tried pumping it up because I hadn't run through any glass or
goatheads so I was wondering if my girlfriend was playing a joke on me,
and it lost air almost as fast as I pumped. When I took the tube out of
the tire it was obvious where the leak was.

Greg
--
"All my time I spent in heaven
Revelries of dance and wine
Waking to the sound of laughter
Up I'd rise and kiss the sky" - The Mekons

Werehatrack said:

On Wed, 08 Mar 2006 23:26:53 -0800, "G.T." <[email hidden]>

Quoted message said:

These 23-28 Kenda tubes came with some wheels and 32mm tires I bought
cheap, the tubes seemed a little small but I don't know if that is what
caused this problem:

http://homepage.mac.com/getosx/puncture.jpg

I'd ridden these tires/tubes 100 miles or so, last ride was on Saturday,
they held air fine until tonight when the front was totally flat.
The hole is the chevron shaped marks to the right of the stem. There
are no sharp edges around the stem hole.

Is this a manufacturing defect? You can make out the beginnings of
similar marks to the left of the stem.

I tend to see this on tubes whose stem area is thick and heavy; I've
also noticed that the stems on these don't fully rise from the hole in
the rim for as much as 15 to 20 minutes after the tire is inflated.
I've been able to reduce such failures to near zero by inflating the
tire twice (or more) so that I get an immediate full rise of the stem
through the valve hole. I think that what's going on is that the
heavy flange at the base of the stem is bridging the channel between
the flanges, leaving a void into which the tube's thinner area next to
the flange then bubbles out and bursts.

That's similar to what I was thinking last night.

Greg

--
"All my time I spent in heaven
Revelries of dance and wine
Waking to the sound of laughter
Up I'd rise and kiss the sky" - The Mekons

G.T. said:

I'd ridden these tires/tubes 100 miles or so, last ride was on Saturday,
they held air fine until tonight when the front was totally flat.
The hole is the chevron shaped marks to the right of the stem. There
are no sharp edges around the stem hole.

Quoted message said:

Is this a manufacturing defect? You can make out the beginnings of
similar marks to the left of the stem.

The quality control of low-cost asian tubes is pretty spotty. I don't
think this would ever happen with a Michelin tube - remember, you get
what you pay for - generally - in the field of bicycling.

- Don Gillies
San Diego, CA

Your tube is too small for the tyre. A 28mm tube in a 32mm tyre is not
a good setup, even if it was cheap.

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

Quoted message said:

G.T. said:

I'd ridden these tires/tubes 100 miles or so, last ride was on Saturday,
they held air fine until tonight when the front was totally flat.
The hole is the chevron shaped marks to the right of the stem. There
are no sharp edges around the stem hole.

Quoted message said:

Is this a manufacturing defect? You can make out the beginnings of
similar marks to the left of the stem.

The quality control of low-cost asian tubes is pretty spotty. I don't
think this would ever happen with a Michelin tube - remember, you get
what you pay for - generally - in the field of bicycling.

Yep, and since these were basically free with the wheels I got a little more
than I paid for, 100 miles. It's nice that it waited a couple of days after
my last ride to go flat.

Greg

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

Quoted message said:

Your tube is too small for the tyre. A 28mm tube in a 32mm tyre is not
a good setup, even if it was cheap.

I realize it was too small but in the past I ran 1.5" tubes in 2.1" tires
for years with very few flats.

Greg

I had this happen with two Wrench Force thornless schraeder valve
tubes. It started out with a large bubble creeping up the valve stem
which then burst.

I've been using Nokia ever since and never had that kind of trouble.

Adam Rush said:

I had this happen with two Wrench Force thornless schraeder valve
tubes. It started out with a large bubble creeping up the valve stem
which then burst.

I've been using Nokia ever since and never had that kind of trouble.

How's the reception on it?
--
Phil, Squid-in-Training

Phil said:

Adam Rush said:

I had this happen with two Wrench Force thornless schraeder valve
tubes. It started out with a large bubble creeping up the valve stem
which then burst.

I've been using Nokia ever since and never had that kind of trouble.

How's the reception on it?

Nice.

Bill "beats my end table remark" S.

(D'oh. That's IKEA.)

G.T. said:

These 23-28 Kenda tubes came with some wheels and 32mm tires I bought
cheap, the tubes seemed a little small but I don't know if that is what
caused this problem:

http://homepage.mac.com/getosx/puncture.jpg

I'd ridden these tires/tubes 100 miles or so, last ride was on Saturday,
they held air fine until tonight when the front was totally flat. The
hole is the chevron shaped marks to the right of the stem. There are no
sharp edges around the stem hole.

Is this a manufacturing defect? You can make out the beginnings of
similar marks to the left of the stem.

Your tube has an injury consistent with an
improper/broken/torn rim liner.

Solid section rims (in which the nipple sticks up into the
inner tube area) need a rubber or polyurethane liner to
cushion the sharp edges of the nipple.

Hollow section rims need a cloth or polyamide (nylon?) rim
liner to keep the tube from herniating into the hollow space.

Also, 23~28 is a wide span of sizes (the Kenda we stock are
23~25 and then 28~32), and some 28 tires are wider than
others. If your tube is relatively small for the tire it
will be more prone to injury. Use the widest tube you can
comfortably install - they all cost the same.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Quoted message said:

G.T. said:

These 23-28 Kenda tubes came with some wheels and 32mm tires I bought
cheap, the tubes seemed a little small but I don't know if that is what
caused this problem:
http://homepage.mac.com/getosx/puncture.jpg

Quoted message said:

I've seen lots of these .. mostly on cheap tubes.. never knew why they
occured and even though I tried very hard to figue it out, I still
don't. but I've seen lots..

Can this merely be a smallish tube? The material is not as
free to stretch where the valve is applied, concentrates
that stretch at the edge of the valve patch.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi said:

G.T. said:

These 23-28 Kenda tubes came with some wheels and 32mm tires I bought
cheap, the tubes seemed a little small but I don't know if that is
what caused this problem:

http://homepage.mac.com/getosx/puncture.jpg

I'd ridden these tires/tubes 100 miles or so, last ride was on
Saturday, they held air fine until tonight when the front was
totally flat. The hole is the chevron shaped marks to the right of the
stem. There are no sharp edges around the stem hole.

Is this a manufacturing defect? You can make out the beginnings of
similar marks to the left of the stem.

Your tube has an injury consistent with an improper/broken/torn rim liner.

I'm using Velox and everything looks fine.

Quoted message said:

Solid section rims (in which the nipple sticks up into the inner tube
area) need a rubber or polyurethane liner to cushion the sharp edges of
the nipple.

I was thinking about that as there are a couple of spokes that poke
through considerably. These were $100 wheels including new tires and
tubes, and are cheaply built. But the spokes closest to the valve hole
feel fine, plus I think the hole isn't at a spoke. I looked all the way
around the inside of the tube and didn't see any other chafing.

Quoted message said:

Hollow section rims need a cloth or polyamide (nylon?) rim liner to keep
the tube from herniating into the hollow space.

Also, 23~28 is a wide span of sizes (the Kenda we stock are 23~25 and
then 28~32), and some 28 tires are wider than others. If your tube is
relatively small for the tire it will be more prone to injury. Use the
widest tube you can comfortably install - they all cost the same.

Yep.

Greg

--
"All my time I spent in heaven
Revelries of dance and wine
Waking to the sound of laughter
Up I'd rise and kiss the sky" - The Mekons

At 120 psi, crystal clear.

Adam Rush said:

At 120 psi, crystal clear.

Crystal clear what?

Greg

--
"All my time I spent in heaven
Revelries of dance and wine
Waking to the sound of laughter
Up I'd rise and kiss the sky" - The Mekons

In article <[email hidden]>, G.T.

Quoted message said:

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

Quoted message said:

Your tube is too small for the tyre. A 28mm tube in a 32mm tyre is not
a good setup, even if it was cheap.

I realize it was too small but in the past I ran 1.5" tubes in 2.1" tires
for years with very few flats.

I routinely ride tubes spec'ed for tire sizes smaller than those
they're inflated in - usually 23-25c size tubes in 28c tires. I've even
run that size tube in a 32mm tire as well, though that may be the
limit. Never a failure such as that in the OP's photo though.

Luke