tire/tube compatibility

Quoted message said:

Hello there,

I replaced a tire and shortly afterwards the tube was pinched. I was
going to put in a new tube and found the tube actually could not
get fully stretched -- it naturally developed some folds. I suspect
that
was why my tube got pinched. FYI, the tires are marked 26"x1.5", and
the tubes 26"x1.9". Could the sizing compatibility really be the
issue?

Yes. A tube that inflates with wrinkles inside the tire will fail in
short order. Some tubes will work with a wider range of tire sizes
than marked, but if the tube is visually too large when inflated just
to the point at which it achieves a round profile, then it's too big
to use in the tire. I have some tubes that are marked 26x1.9 to
26x2.1 which work just fine in a 26x1.5 tire, but I have others that
are marked for the same size and are much too large for the 26x1.5.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

Where's the hatrack said:

Quoted message said:

I replaced a tire and shortly afterward the tube was pinched. I
was going to put in a new tube and found the tube actually could
not get fully stretched -- it naturally developed some folds. I
suspect that was why my tube got pinched. FYI, the tires are
marked 26"x1.5", and the tubes 26"x1.9". Could the sizing
compatibility really be the issue?

Quoted message said:

Yes. A tube that inflates with wrinkles inside the tire will fail
in short order.

That's an old myth. I've used 700c tubes in 24" tires and pushed
oversized tubes in smaller tires. It's not easy and that's why you
don't want to do it. I've helped out a MTB rider with my 700c spare
tube that is too long for a fat 26" tire and required folding. That
these will fail is a neatness fetish. You need to ask yourself what
would cause the failure. I've removed tubes from tires in which they
served for hundreds of miles with an obvious fold.

If you never have a flat in thousands of miles, the tube might fail at
a fold because rubber oxidizes more rapidly when stretched but then
that similarly affects undersized 1/2" diameter noodles of inner tubes
that riders use to save weight. You don't see them worrying about
oxidation failures. I became familiar with folded tubes in the days
when car tires weren't tubeless. That's where folds occurred often
and didn't fail.

Quoted message said:

Some tubes will work with a wider range of tire sizes than marked,
but if the tube is visually too large when inflated just to the
point at which it achieves a round profile, then it's too big to use
in the tire. I have some tubes that are marked 26x1.9 to 26x2.1
which work just fine in a 26x1.5 tire, but I have others that are
marked for the same size and are much too large for the 26x1.5.

That's fine, except it doesn't cause tube failures.

Jobst Brandt

Quoted message said:

Quoted message said:

Yes. A tube that inflates with wrinkles inside the tire will fail
in short order.

That's an old myth. I've used 700c tubes in 24" tires and pushed
oversized tubes in smaller tires. It's not easy and that's why you
don't want to do it. I've helped out a MTB rider with my 700c spare
tube that is too long for a fat 26" tire and required folding. That
these will fail is a neatness fetish. You need to ask yourself what
would cause the failure. I've removed tubes from tires in which they
served for hundreds of miles with an obvious fold.

That is not a myth. Tubes will fail from simple abrassion with a patch on a
tire casing, or the edge of a Mr. Tuffy. I've seen this often. I suspect
your sample size is insufficient to recognize the problem, or, in your
personal use, you use relatively-heavy tubes that are going to be less
vulnerable to that sort of failure.

I have seen tubes fail at the point where they've been folded over. It does
happen. It's not exceptionally common, probably because there are only two
likely reasons for a tube to be folded over in that fashion. First, because
somebody installed too-large a tube, which isn't going to happen that often.
Second, because a wheel (particularly a rear wheel) was ridden with
too-little air, causing the tire to creep around the rim, carrying the tube
with it as much as it can, with results in the tube bunching up near the
valve on one side (and stretched thin on the opposite). In that case, the
tube invariably fails not because it's been folded over, but because it
tears at the valve base.

On a thin tube (which most are these days), it doesn't take much more than
time and the normal forces that act upon a tube to create problems where
there are significant irregularities. As I mentioned, Mr. Tuffys and tire
casing patches are the most-common causes (and for that reason I never
recommend a Mr. Tuffy or with a lightweight tube, and casing patches, such
as the Park, should be considered temporary fixes with light tubes).

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

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

Quoted message said:

Where's the hatrack said:

Quoted message said:

I replaced a tire and shortly afterward the tube was pinched. I
was going to put in a new tube and found the tube actually could
not get fully stretched -- it naturally developed some folds. I
suspect that was why my tube got pinched. FYI, the tires are
marked 26"x1.5", and the tubes 26"x1.9". Could the sizing
compatibility really be the issue?

Quoted message said:

Yes. A tube that inflates with wrinkles inside the tire will fail
in short order.

That's an old myth. I've used 700c tubes in 24" tires and pushed
oversized tubes in smaller tires. It's not easy and that's why you
don't want to do it. I've helped out a MTB rider with my 700c spare
tube that is too long for a fat 26" tire and required folding. That
these will fail is a neatness fetish. You need to ask yourself what
would cause the failure. I've removed tubes from tires in which they
served for hundreds of miles with an obvious fold.

If you never have a flat in thousands of miles, the tube might fail at
a fold because rubber oxidizes more rapidly when stretched but then
that similarly affects undersized 1/2" diameter noodles of inner tubes
that riders use to save weight. You don't see them worrying about
oxidation failures. I became familiar with folded tubes in the days
when car tires weren't tubeless. That's where folds occurred often
and didn't fail.

Quoted message said:

Some tubes will work with a wider range of tire sizes than marked,
but if the tube is visually too large when inflated just to the
point at which it achieves a round profile, then it's too big to use
in the tire. I have some tubes that are marked 26x1.9 to 26x2.1
which work just fine in a 26x1.5 tire, but I have others that are
marked for the same size and are much too large for the 26x1.5.

That's fine, except it doesn't cause tube failures.

Jobst Brandt

Mike Jacoubowsky said:

Quoted message said:

Quoted message said:

Yes. A tube that inflates with wrinkles inside the tire will fail
in short order.

Quoted message said:

Quoted message said:

That's an old myth. I've used 700c tubes in 24" tires and pushed
oversized tubes in smaller tires. It's not easy and that's why you
don't want to do it. I've helped out a MTB rider with my 700c
spare tube that is too long for a fat 26" tire and required
folding. That these will fail is a neatness fetish. You need to
ask yourself what would cause the failure. I've removed tubes from
tires in which they served for hundreds of miles with an obvious
fold.

Quoted message said:

That is not a myth. Tubes will fail from simple abrassion with a
patch on a tire casing, or the edge of a Mr. Tuffy. I've seen this
often. I suspect your sample size is insufficient to recognize the
problem, or, in your personal use, you use relatively-heavy tubes
that are going to be less vulnerable to that sort of failure.

I said nothing about patches or rough edges bearing on an inner tube.
I said the fold in a tube does not cause a failure.

Quoted message said:

I have seen tubes fail at the point where they've been folded over.
It does happen. It's not exceptionally common, probably because
there are only two likely reasons for a tube to be folded over in
that fashion. First, because somebody installed too-large a tube,
which isn't going to happen that often. Second, because a wheel
(particularly a rear wheel) was ridden with too-little air, causing
the tire to creep around the rim, carrying the tube with it as much
as it can, with results in the tube bunching up near the valve on
one side (and stretched thin on the opposite). In that case, the
tube invariably fails not because it's been folded over, but because
it tears at the valve base.

As I said, oversized tubes must be folded or wrinkled and this occurs
more with fat tires than with the scrawny tubes people tend to use in
their "racing" bicycles in order to reduce the dread rotating mass
that hinders twice as much as non-rotating mass on the bicycle... if
you want to believe that.

Quoted message said:

On a thin tube (which most are these days), it doesn't take much
more than time and the normal forces that act upon a tube to create
problems where there are significant irregularities. As I
mentioned, Mr. Tuffys and tire casing patches are the most-common
causes (and for that reason I never recommend a Mr. Tuffy or with a
lightweight tube, and casing patches, such as the Park, should be
considered temporary fixes with light tubes).

You'll have to explain what causes the tube failure. At more than
50psi, there is no relative motion between tube and tire or rim. This
should be obvious by how well the tube is stuck to the tire if you
aren't a talcum faddist. I don't know why you bring up tire liners.
They cause failures all by themselves but not from folds in tubes.

Jobst Brandt

Mike Jacoubowsky said:

That is not a myth. Tubes will fail from simple abrassion with a patch on a
tire casing, or the edge of a Mr. Tuffy. I've seen this often. I suspect
your sample size is insufficient to recognize the problem, or, in your
personal use, you use relatively-heavy tubes that are going to be less
vulnerable to that sort of failure.

Well I had it happen when I tried using some wider tubes on a 24" road
tire that was 1.5", versus the old 2.125" wide tire that was on there
previously. I though it was all just fine after the wider tube was in
there, but after an hour or so the tube failed.

Steven Scharf said:

Quoted message said:

That is not a myth. Tubes will fail from simple abrassion with a
patch on a tire casing, or the edge of a Mr. Tuffy. I've seen
this often. I suspect your sample size is insufficient to
recognize the problem, or, in your personal use, you use
relatively-heavy tubes that are going to be less vulnerable to that
sort of failure.

Quoted message said:

Well I had it happen when I tried using some wider tubes on a 24"
road tire that was 1.5", versus the old 2.125" wide tire that was on
there previously. I though it was all just fine after the wider
tube was in there, but after an hour or so the tube failed.

Could you describe the failure you found on inspecting the tube that
makes you sure that a fold caused the leak? The claim above that
thicker tube are less susceptible to such failures makes the scenario
less credible because bending stress decreases with decreasing wall
thickness. As I said, I have seen not only bicycle tire inner tubes
but those of car tires that ran more than a thousand miles with a
wrinkle.

Jobst Brandt

In article <[email hidden]>, Werehatrack

() said:

Yes. A tube that inflates with wrinkles inside the tire will fail in
short order. Some tubes will work with a wider range of tire sizes
than marked, but if the tube is visually too large when inflated just
to the point at which it achieves a round profile, then it's too big
to use in the tire. I have some tubes that are marked 26x1.9 to
26x2.1 which work just fine in a 26x1.5 tire, but I have others that
are marked for the same size and are much too large for the 26x1.5.

Both Schwalbe and Conti sell inner tubes marked "406/451", which are
sized to fit in the latter diameter tyre and thus get quite seriously
folded when used in the former. All the flats I encountered when using
these tubes in 406 tyres were caused by the traditional method of sharp
things coming through from outside. I switched to using Schwalbe's SV5
tubes, labelled "355/406", which fit quite nicely, but I am told that
they now do a 406-specific tube. Typical, really, when I have three in
service and another five as spares.

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
Like Kant, it is my wish to create my own individual epistemology. But I
also wish to find out what is for pudding.

did you talc the tube before inserting it into the tire? it may have
bound up inside the tire if it couldn't reposition itself as you
inflated it.This can be especially important with new tubes/tires, as
the rubber is still soft.

- -
Comments and opinions compliments of,
"Your Friendly Neighborhood Wheelman"

My web Site:
http://geocities.com/czcorner

To E-mail me:
ChrisZCorner "at" webtv "dot" net

Jobst Brandt said:

As I said, oversized tubes must be folded or wrinkled and this occurs
more with fat tires than with the scrawny tubes people tend to use in
their "racing" bicycles in order to reduce the dread rotating mass
that hinders twice as much as non-rotating mass on the bicycle... if
you want to believe that.

You forgot to mention the dread rolling resistance.
--
Terry Morse - Undiscovered Country Tours - http://udctours.com

Chris Z The Wheelman said:

did you talc the tube before inserting it into the tire? it may have
bound up inside the tire if it couldn't reposition itself as you
inflated it.This can be especially important with new tubes/tires, as
the rubber is still soft.

I don't think this is necessary. I've never put talc on a tube and never
had one of these "chafing" flats. I think talc is now cornstarch, what
happens after you ride in the rain?

Peter Cole said:

I don't think this is necessary. I've never put talc on a tube and never
had one of these "chafing" flats. I think talc is now cornstarch, what
happens after you ride in the rain?

You get non-newtonian tires?

--
Dane Buson - [email hidden]
/earth is 98% full ... please delete anyone you can.

"Dane Buson" wrote: You get non-newtonian tires?
^^^^^^^^^^^^^^^
What a great idea for development. You sprinkle this "magic"
(non-newtonian) powder on the tube, and it becomes very slippery while it is
being installed, but then becomes sticky after it is installed. With all
movement eliminated, rolling resistance is lowered, and chafing around the
edge of a boot can no longer occur.