Puncture proofing

On Wed, 30 Mar 2005 09:11:40 +0200, Dieter Britz <[email hidden]>

may have said:

You can get these flat plastic strips that you put between the tyre and
tube, to prevent punctures. We discussed this here a year or so ago,
where it was pointed out why they work (increase the path length to the
tube a sharp object has to go).

I tried to buy some at a local shop the other day, and was told that
the reason they didn't have it was, that the plastic strips are known
to crack with age, and then ... (I didn't hear the rest of what the
bloke said, as we were interrupted).

Are there some known problems with these plastic strips? I thought
they were The Answer.

Known failure-related problems that I've heard about include eventual
chafing of the tube at the overlap point if it's the type with a
non-tapered edge. I have not heard of them cracking with age, though
I suppose there are probably versions which have that failing,
particularly if they're made of polyurethane. Even if this is a valid
issue, using them is probably preferable to doing without for riders
in a high-puncture environment.

None of this addresses the performance issues, of course.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

On Wed, 30 Mar 2005 09:11:40 +0200, Dieter Britz <[email hidden]>

may have said:

You can get these flat plastic strips that you put between the tyre and
tube, to prevent punctures. We discussed this here a year or so ago,
where it was pointed out why they work (increase the path length to the
tube a sharp object has to go).

I tried to buy some at a local shop the other day, and was told that
the reason they didn't have it was, that the plastic strips are known
to crack with age, and then ... (I didn't hear the rest of what the
bloke said, as we were interrupted).

Are there some known problems with these plastic strips? I thought
they were The Answer.

Known failure-related problems that I've heard about include eventual
chafing of the tube at the overlap point if it's the type with a
non-tapered edge. I have not heard of them cracking with age, though
I suppose there are probably versions which have that failing,
particularly if they're made of polyurethane. Even if this is a valid
issue, using them is probably preferable to doing without for riders
in a high-puncture environment.

None of this addresses the performance issues, of course.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

Dieter Britz said:

You can get these flat plastic strips that you put between the tyre and
tube, to prevent punctures. We discussed this here a year or so ago,
where it was pointed out why they work (increase the path length to the
tube a sharp object has to go).

I tried to buy some at a local shop the other day, and was told that
the reason they didn't have it was, that the plastic strips are known
to crack with age, and then ... (I didn't hear the rest of what the
bloke said, as we were interrupted).

Are there some known problems with these plastic strips? I thought
they were The Answer.

Dear Dieter,

Perhaps some other brands of tire liners might be made of a
plastic that eventually cracks, but the 10-year-old Mr.
Tuffy tire liner strips that I stopped using are still
pliable and would work just fine.

They did reduce the number of flat tires that I tracked on
the same daily route, where goathead thorns are the main
problem.

Their drawbacks include more rolling resistance and more
fuss fixing flats and mounting new tires.

Some people mention problems with the end of the strip
chafing the inner tube, so they suggest feathering the ends
in various ways. I never had that problem, but I also used
thicker thorn-resistant inner tubes and replaced them fairly
often.

Carl Fogel

Dieter Britz said:

You can get these flat plastic strips that you put between the tyre and
tube, to prevent punctures. We discussed this here a year or so ago,
where it was pointed out why they work (increase the path length to the
tube a sharp object has to go).

I tried to buy some at a local shop the other day, and was told that
the reason they didn't have it was, that the plastic strips are known
to crack with age, and then ... (I didn't hear the rest of what the
bloke said, as we were interrupted).

Are there some known problems with these plastic strips? I thought
they were The Answer.

Dear Dieter,

Perhaps some other brands of tire liners might be made of a
plastic that eventually cracks, but the 10-year-old Mr.
Tuffy tire liner strips that I stopped using are still
pliable and would work just fine.

They did reduce the number of flat tires that I tracked on
the same daily route, where goathead thorns are the main
problem.

Their drawbacks include more rolling resistance and more
fuss fixing flats and mounting new tires.

Some people mention problems with the end of the strip
chafing the inner tube, so they suggest feathering the ends
in various ways. I never had that problem, but I also used
thicker thorn-resistant inner tubes and replaced them fairly
often.

Carl Fogel

Quoted message said:

On Wed, 30 Mar 2005 09:11:40

+0200, Dieter Britz

Quoted message said:

Quoted message said:

You can get these flat plastic strips that you put between the tyre and
tube, to prevent punctures. We discussed this here a year or so ago,
where it was pointed out why they work (increase the path length to the
tube a sharp object has to go).
I tried to buy some at a local shop the other day, and was told that
the reason they didn't have it was, that the plastic strips are known
to crack with age, and then ... (I didn't hear the rest of what the
bloke said, as we were interrupted).
Are there some known problems with these plastic strips? I thought
they were The Answer.

Quoted message said:

Perhaps some other brands of tire liners might be made of a
plastic that eventually cracks, but the 10-year-old Mr.
Tuffy tire liner strips that I stopped using are still
pliable and would work just fine.

They did reduce the number of flat tires that I tracked on
the same daily route, where goathead thorns are the main
problem.

Their drawbacks include more rolling resistance and more
fuss fixing flats and mounting new tires.

Some people mention problems with the end of the strip
chafing the inner tube, so they suggest feathering the ends
in various ways. I never had tha t problem, but I also used
thicker thorn-resistant inner tubes and replaced them fairly
often.

In my experience, polyurethane liners do indeed stay pliable
for a very long time. I haven't seen a cracked one. If they
_were_ to crack, it wouldn't be in the no-UV darkness where
oxygen doesn't circulate.

As with Carl's report, I also find them not too troublesome
when used at relatively low (60psi) pressure with an amply
thick tube, properly installed.

But bicycle mechanics get that pained look when we find the
things folded over themselves inside your tire. They are
clumsy to install evenly in smaller tires, where it's not at
all unusual to find the edge of a polyurethane liner has cut
through your tube.

Polyurethane has no particular resistance to punctures,
merely relying on its 3mm depth in a world of hopefully
2.5mm pointy objects.

Mechanics can fail at communicating all that well, the
customer hearing "I'm leaving out your expensive liners"

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

Just to add, I have also used Mr Tuffy liners without problem, but I
have had exactly the problems described with polyurethane liners.
These started flxible and supple but ended up brittle, dry and cracked
- also seemed to degrade the inner tube giving a crazed layer of cracks
over much of it. This happened front and rear. I attributed it to
plasticisers in the polyurethane leaching into the inner tube rubber
over time.

Andrew Webster

Andrew W said:

Just to add, I have also used Mr Tuffy liners without problem, but I
have had exactly the problems described with polyurethane liners.
These started flxible and supple but ended up brittle, dry and cracked
- also seemed to degrade the inner tube giving a crazed layer of cracks
over much of it. This happened front and rear. I attributed it to
plasticisers in the polyurethane leaching into the inner tube rubber
over time.

Andrew Webster

Dear Andrew,

You could be right that the liners degrade over years of
contact--the ones that I have that are still soft and
pliable have been coiled up in a junk box for years, not
inside tires.

And now that I think of it, I remember that the Mr. Tuffy
liners would eventually stick fiercely to the tubes--pull
the tube out of the tire and there was the liner, as if it
was glued.

I also remember that it was impossible to get them to sit
evenly inside the tire--they always swerved from side to
side, sometimes riding up on one sidewall, then the other.

But my records left no doubt that they reduced flat tires
over the same daily ride, year by year in goathead country.
With them on 27-inch tires with thorn-resistant tubes, the
number of flats per year dropped into the single digits.
With 700c tires and thin Slime tubes, I average 30 to 50
flats per year, even riding out in the traffic lane instead
of on the shoulder. And it's common to find that the Slime
has sealed several pinhole punctures when a tire finally
goes flat.

Carl Fogel

I may not have made myself clear.

My experience with Mr Tuffy liners is exactly as yours. Mine have not
degraded over several years of use.

It is other liners (no brand name, but described as polyurethane tyre
liners) that have caused me the problems. These were a much softer
plastic than the Mr Tuffy liners when new, but degraded to thin,
brittle strips.

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

Quoted message said:

Andrew W said:

Just to add, I have also used Mr Tuffy liners without problem, but I
have had exactly the problems described with polyurethane liners.
These started flxible and supple but ended up brittle, dry and cracked
- also seemed to degrade the inner tube giving a crazed layer of cracks
over much of it. This happened front and rear. I attributed it to
plasticisers in the polyurethane leaching into the inner tube rubber
over time.

Andrew Webster

Dear Andrew,

You could be right that the liners degrade over years of
contact--the ones that I have that are still soft and
pliable have been coiled up in a junk box for years, not
inside tires.

And now that I think of it, I remember that the Mr. Tuffy
liners would eventually stick fiercely to the tubes--pull
the tube out of the tire and there was the liner, as if it
was glued.

I also remember that it was impossible to get them to sit
evenly inside the tire--they always swerved from side to
side, sometimes riding up on one sidewall, then the other.

But my records left no doubt that they reduced flat tires
over the same daily ride, year by year in goathead country.
With them on 27-inch tires with thorn-resistant tubes, the
number of flats per year dropped into the single digits.
With 700c tires and thin Slime tubes, I average 30 to 50
flats per year, even riding out in the traffic lane instead
of on the shoulder. And it's common to find that the Slime
has sealed several pinhole punctures when a tire finally
goes flat.

Carl Fogel

I'm sure your territory has its selling points, but over here I've gone as
much as a year (at over 5000 mi/yr) without a flat and it's about 7 months
now since my last using normal tubes and 700x23 tires. Before this streak I
had a slew of flats using a used Michelin Pro that seemed to attract and
become impregnated by bits of anything sharp, whereupon I finally broke down
and bought a new tire and replaced the frame pump with a CO2 inflator that I
have never had the opportunity to use.

--Art

In article <[email hidden]>,

Dieter Britz said:

You can get these flat plastic strips that you put between the tyre and
tube, to prevent punctures. We discussed this here a year or so ago,
where it was pointed out why they work (increase the path length to the
tube a sharp object has to go).

I tried to buy some at a local shop the other day, and was told that
the reason they didn't have it was, that the plastic strips are known
to crack with age, and then ... (I didn't hear the rest of what the
bloke said, as we were interrupted).

Are there some known problems with these plastic strips? I thought
they were The Answer.

I have a pair that were in my bike when I found it in a friend's
attic. He'd been living there ten years and didn't even know about the
bike! They're still pliable.
I wound up trimming away the bit that overlapped because it was
causing a bald spot on the tire. I left it a bit long so I have to push
the liner into the tire and the seam stays closed, and I stuck it in
place with a bit of electrical tape at the seam and a couple other
places to make installing the tire easy.
I also use tire sealant that I picked up at Walmart. I went from
patching & pumping daily to no patches in a month and only pumping it up
once every few days to a week. I don't know if I need even that--I
think I lose more pressure hooking up the pump than I do from leakage.
YMMV, though. My road hazards are thousands of tiny shards of glass
that accumulate from all the drunken kids driving around on weekends.
Bigger stuff would probably defeat my system as I doubt my cheap tire
sealant could deal with a nail. And no telling if it's wreaking havoc
on my old patches since I haven't had the tires off since putting it in.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

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

Quoted message said:

In article <[email hidden]>,

Dieter Britz said:

You can get these flat plastic strips that you put between the tyre and
tube, to prevent punctures. We discussed this here a year or so ago,
where it was pointed out why they work (increase the path length to the
tube a sharp object has to go).

I tried to buy some at a local shop the other day, and was told that
the reason they didn't have it was, that the plastic strips are known
to crack with age, and then ... (I didn't hear the rest of what the
bloke said, as we were interrupted).

Are there some known problems with these plastic strips? I thought
they were The Answer.

I have a pair that were in my bike when I found it in a friend's
attic. He'd been living there ten years and didn't even know about the
bike! They're still pliable.
I wound up trimming away the bit that overlapped because it was
causing a bald spot on the tire. I left it a bit long so I have to push
the liner into the tire and the seam stays closed, and I stuck it in
place with a bit of electrical tape at the seam and a couple other
places to make installing the tire easy.
I also use tire sealant that I picked up at Walmart. I went from
patching & pumping daily to no patches in a month and only pumping it up
once every few days to a week. I don't know if I need even that--I
think I lose more pressure hooking up the pump than I do from leakage.
YMMV, though. My road hazards are thousands of tiny shards of glass
that accumulate from all the drunken kids driving around on weekends.
Bigger stuff would probably defeat my system as I doubt my cheap tire
sealant could deal with a nail. And no telling if it's wreaking havoc
on my old patches since I haven't had the tires off since putting it in.

--
B.B. --I am not a goat! thegoat4 at airmail dot net
http://web2.airmail.net/thegoat4/

I don't know why they haven't *invented* kevlar tire liners yet.
Ken

On Sun, 10 Apr 2005 07:02:29 -0400, "Ken"
<[email hidden]> wrote:

[snip]

Quoted message said:

I don't know why they haven't *invented* kevlar tire liners yet.
Ken

Dear Ken,

Some tires have a Kevlar belt (not bead) built in. But such
belts and the separate Kevlar tire liners are made of woven
threads that help mostly when something big tries to gash
the tire.

Small, pointy debris like a goathead thorn goes right
between the woven Kevlar threads, like a needle through
steel wool. What little protection Kevlar offers against
thorns is just the slight extra thickness--a short thorn may
not reach the inner tube.

On the other hand, solid strips of tough, flexible plastic
like Mr. Tuffy can stop a lot of those small thorns--the
plastic is surprisingly resistant to a goathead. But the
solid strips don't roll well.

Carl Fogel

Dieter Britz said:

You can get these flat plastic strips that you put between the tyre

and

Quoted message said:

tube, to prevent punctures.

[...]

Quoted message said:

Are there some known problems with these plastic strips? I thought
they were The Answer.

The Answer to preventing punctures is the Schwalbe Marathon Plus. 1cm
of rubber to the tube. Forget the dinky 3mm of a liner.

I think these should solve just about anybody's puncture problem.

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

Quoted message said:

On Sun, 10 Apr 2005 07:02:29 -0400, "Ken"
<[email hidden]> wrote:

[snip]

Quoted message said:

I don't know why they haven't *invented* kevlar tire liners yet.
Ken

Dear Ken,

Some tires have a Kevlar belt (not bead) built in. But such
belts and the separate Kevlar tire liners are made of woven
threads that help mostly when something big tries to gash
the tire.

Yes I am aware that some tires have the kevlar in them, depends on the maker
of the tire and the size.

Quoted message said:

Small, pointy debris like a goathead thorn goes right
between the woven Kevlar threads, like a needle through
steel wool. What little protection Kevlar offers against
thorns is just the slight extra thickness--a short thorn may
not reach the inner tube.

And yes, that is how a *cop killer* bullet is shaped.

Quoted message said:

On the other hand, solid strips of tough, flexible plastic
like Mr. Tuffy can stop a lot of those small thorns--the
plastic is surprisingly resistant to a goathead. But the
solid strips don't roll well.

Yeah I would think putting something semi-solid in the tire / rim might make
it ride differently.

Quoted message said:

Carl Fogel

Ken said:

I don't know why they haven't *invented* kevlar tire liners yet.
Ken

For the purpose of this discussion, Kevlar == aramid.