Cycling home the other evening I suddenly experienced a front tyre 
deflation.  This is partcularly un nerving on the bent and even more so when 
you're in the feeder lane on to the A3!

Still made it to the verge to rectify what I assumed was just a normal 
puncture caused by road debris.

When I removed the tyre I found a long strand of thin metal wire had come 
lose inside the tyre and the end of this had punctured the tube.  At first I 
thought that somehow this wire had worked its way into the tyre from the 
road - although a couple of seconds thought made me realise how ridiculous 
this was.  What appears to have happened is the metal strengthening in the 
bead of the tyre had become uncovered.  I am naive enough to not even 
realise cycle tyres had steel beads!

I've not used a lot of Schwalbe tyres but this seems a very unusual failure. 
Has anyone elese experienced this sort of thing with a Schwalbe or any other 
make?

It proved quite tricky to break the wire so as I could replace the tyre and 
minimise the risk of re puncture from a sharp wire stub.  Unfortunately I 
didn't think to photograph the failure in all its glory.

I'm guessing the tyre is useless now so have ordered another.


Matt

By the way no less than 4 cyclists passing by my stricken machine checked I 
was OK - one even offered me a spare tube.  Restores your faith....

Matt wrote:
> Cycling home the other evening I suddenly experienced a front tyre
> deflation.  This is partcularly un nerving on the bent and even more
> so when you're in the feeder lane on to the A3!
>
> Still made it to the verge to rectify what I assumed was just a normal
> puncture caused by road debris.
>
> When I removed the tyre I found a long strand of thin metal wire had
> come lose inside the tyre and the end of this had punctured the tube.
> At first I thought that somehow this wire had worked its way into the
> tyre from the road - although a couple of seconds thought made me
> realise how ridiculous this was.  What appears to have happened is
> the metal strengthening in the bead of the tyre had become uncovered.
> I am naive enough to not even realise cycle tyres had steel beads!

That's true of all normal non-folding tyres, and that's why they don't 
collapse when you remove them from the wheel.  Folding tyres have floppy 
kevlar beads.

> I've not used a lot of Schwalbe tyres but this seems a very unusual
> failure. Has anyone elese experienced this sort of thing with a
> Schwalbe or any other make?

It's quite a common failure with various tyres for the sidewall to split 
(under-inflation is one cause of this), but I've not heard of a bead 
separating without the sidewall failing.

You could try getting a refund if you bought the tyre not too long ago.

~PB

Pete Biggs wrote:
> Matt wrote:

>> I've not used a lot of Schwalbe tyres but this seems a very unusual
>> failure. Has anyone elese experienced this sort of thing with a
>> Schwalbe or any other make?

I have never seen this in any tyre I have owned.

> It's quite a common failure with various tyres for the sidewall to split 
> (under-inflation is one cause of this), but I've not heard of a bead 
> separating without the sidewall failing.
> 
> You could try getting a refund if you bought the tyre not too long ago.

If the tyre is in good condition (apart from this failure), then I would 
expect a refund, if not from the shop then send it make to the 
manufacturers

Martin.

"Matt"  considered Thu, 21 Aug 2008 21:39:14 +0100 the
perfect time to write:

>Cycling home the other evening I suddenly experienced a front tyre 
>deflation.  This is partcularly un nerving on the bent and even more so when 
>you're in the feeder lane on to the A3!
>
>Still made it to the verge to rectify what I assumed was just a normal 
>puncture caused by road debris.
>
>When I removed the tyre I found a long strand of thin metal wire had come 
>lose inside the tyre and the end of this had punctured the tube.  At first I 
>thought that somehow this wire had worked its way into the tyre from the 
>road - although a couple of seconds thought made me realise how ridiculous 
>this was.  What appears to have happened is the metal strengthening in the 
>bead of the tyre had become uncovered.  I am naive enough to not even 
>realise cycle tyres had steel beads!
>
>I've not used a lot of Schwalbe tyres but this seems a very unusual failure. 
>Has anyone elese experienced this sort of thing with a Schwalbe or any other 
>make?
>
>It proved quite tricky to break the wire so as I could replace the tyre and 
>minimise the risk of re puncture from a sharp wire stub.  Unfortunately I 
>didn't think to photograph the failure in all its glory.
>
>I'm guessing the tyre is useless now so have ordered another.
>
>
>Matt
>
>By the way no less than 4 cyclists passing by my stricken machine checked I 
>was OK - one even offered me a spare tube.  Restores your faith.... 
>
I had a front blowout on a club ride a couple of weeks ago, caused by
a Schwalbe Marathon coming adrift from it's bead wires.
The bang was pretty impressive, and of course the tube was a write
off.

We booted the cover with a toothpaste tube so I could complete the
ride (thanks to another rider - I wouldn't have known to carry that).
This meant wrapping the toothpaste tube all round the inside of the
cover, folding it around the bead, and snugging the bead firmly into
the rim to allow inflation pressure to hold it all in place.
The excess toothpaste tube was then trimmed back level with the edge
of the rim, to avoid it catching on the brake blocks.

I'm planning on getting some pictures of the technique online, as it
may prove invaluable for others in a similar situation.
It will most likely be on the CTC Cambridge DA site.

I did over 30 miles with it in that condition before getting home, and
it survived ok, although I must admit to being rather nervous on
descents.  It was a bit lumpy in feel as well.

When we met up with the riders who'd done the longer route at tea, one
of them guessed correctly what tyre I used from the damage I
described, despite having never seen the bike.

Makes you wonder about Schwalbe QC, although it could equally well be
tyre lever abuse at some stage over the life of the tyre (I've only
had the bike since august 1st).

I can't be sure of the age of them, but wear is minimal.The only
marking on the tyre that I can't account for is 9902, which could be a
date code (1999, week 2?).
I changed both tyres, as I can't have any confidence in them after
that.
I Got some Ultra Gatorskins which seem to suit the bike well.

I've learned several things from the experience:
1) carry an old toothpaste tube in the repair kit, with the ends cut
off to save space.
2) always examine beads for sny signs of damage or wire exposure
whenever you have the tyre off.
3) it's amazing what you can still ride on, if you have to.
-- 

There are 10 types of people in the world - those who understand binary and those who don't!

On Aug 22, 9:03 am, Phil W Lee <phil(at)lee-family(dot)me(dot)uk>
wrote:


>
> I've learned several things from the experience:
> 1) carry an old toothpaste tube in the repair kit, with the ends cut
> off to save space.

I've mentioned it before, but a section of a tyvek envelope sounds
more suitable than a toothpaste tube, and has saved a couple of rides
for us (including 60 miles on a fully laden tandem). It is really
tough stuff, but very easy to use.

James

On 22 Aug, 02:19, "james.an...@gmail.com" 
wrote:
> On Aug 22, 9:03 am, Phil W Lee <phil(at)lee-family(dot)me(dot)uk>
> wrote:
>
>
>
> > I've learned several things from the experience:
> > 1) carry an old toothpaste tube in the repair kit, with the ends cut
> > off to save space.
>
> I've mentioned it before, but a section of a tyvek envelope sounds
> more suitable than a toothpaste tube, and has saved a couple of rides
> for us (including 60 miles on a fully laden tandem). It is really
> tough stuff, but very easy to use.

These sound like fine kludges. I thought I would mention
that I have repaired a mountain bike tyre that
had the bead seperate due to brake block abrasion,
by stiching it with ordinary needle and thread obtained
from a nearby hotel. As far as I am aware (not my bike)
the tyre perfomed flawlessly for the rest of the day. Of course
the pressure was lower than that typical in a road tyre so I would
suppose that any tyre distorsion would be less.

Matt wrote:
> Cycling home the other evening I suddenly experienced a front tyre 
> deflation.  This is partcularly un nerving on the bent and even more so when 
> you're in the feeder lane on to the A3!
> 
> Still made it to the verge to rectify what I assumed was just a normal 
> puncture caused by road debris.
> 
> When I removed the tyre I found a long strand of thin metal wire had come 
> lose inside the tyre and the end of this had punctured the tube.  At first I 
> thought that somehow this wire had worked its way into the tyre from the 
> road - although a couple of seconds thought made me realise how ridiculous 
> this was.  What appears to have happened is the metal strengthening in the 
> bead of the tyre had become uncovered.  I am naive enough to not even 
> realise cycle tyres had steel beads!

<snip>

That's interesting, mate of mine had one go exactly the same way about 3 
months ago.  Would seem to me Schwalbe should tidy up their quality 
control.  I hope this isn't symptomatic cos I love those tyres for 
commuting and mind will get replaced in the spring.

Btw, if you have the receipt, I'd say its a deffo replacement job.

A friend of mine had NINE yes NINE punctures on a day while
cycletouring in Spain a few years ago. We were riding separately for
the day. I diagnosed an exposed wire, just as you describe. I always
carry bits of canvas and glued one over it. End of problem. Still have
bits of canvas tape from old tubular tyres from 15+ years ago!

Quoting  james.annan@gmail.com :
>On Aug 22, 9:03 am, Phil W Lee <phil(at)lee-family(dot)me(dot)uk>
>>1) carry an old toothpaste tube in the repair kit, with the ends cut
>>off to save space.
>I've mentioned it before, but a section of a tyvek envelope sounds
>more suitable than a toothpaste tube,

A chunk of dead tyre with the beads cut off works fine, too.
-- 
David Damerell  Distortion Field!
Today is First Thursday, August.

David Damerell  considered 26 Aug
2008 17:59:57 +0100 (BST) the perfect time to write:

>Quoting  james.annan@gmail.com :
>>On Aug 22, 9:03 am, Phil W Lee <phil(at)lee-family(dot)me(dot)uk>
>>>1) carry an old toothpaste tube in the repair kit, with the ends cut
>>>off to save space.
>>I've mentioned it before, but a section of a tyvek envelope sounds
>>more suitable than a toothpaste tube,
>
>A chunk of dead tyre with the beads cut off works fine, too.

Just how would that hold the tyre to the bead wires?

The only way the repair worked was to wrap the patch around the tyre
AND bead, which would not be possible with a section of cover.

A section of cover would be fine for patching a cut, but wouldn't have
helped with this failure mode of the tyre becoming detached from it's
bead wires.
-- 
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

:-)

Quoting  Phil W Lee  <phil(at)lee-family(dot)me(dot)uk>:
>David Damerell  considered 26 Aug
>>Quoting  james.annan@gmail.com :
>>>On Aug 22, 9:03 am, Phil W Lee <phil(at)lee-family(dot)me(dot)uk>
>>>>1) carry an old toothpaste tube in the repair kit, with the ends cut
>>>>off to save space.
>>>I've mentioned it before, but a section of a tyvek envelope sounds
>>>more suitable than a toothpaste tube,
>>A chunk of dead tyre with the beads cut off works fine, too.
>Just how would that hold the tyre to the bead wires?

Oh, fair point. Thought it was the usual boot discussion. Of course I have
duct tape on serious touring, but that does preclude using the relevant
brake...
-- 
David Damerell  Kill the tomato!
Today is First Friday, August.

On 27 Aug 2008 04:46:17 +0100 (BST)
David Damerell  wrote:

> Quoting  Phil W Lee  <phil(at)lee-family(dot)me(dot)uk>:
> >David Damerell  considered 26 Aug
> >>Quoting  james.annan@gmail.com :
> >>>On Aug 22, 9:03 am, Phil W Lee <phil(at)lee-family(dot)me(dot)uk>
> >>>>1) carry an old toothpaste tube in the repair kit, with the ends
> >>>>cut off to save space.
> >>>I've mentioned it before, but a section of a tyvek envelope sounds
> >>>more suitable than a toothpaste tube,
> >>A chunk of dead tyre with the beads cut off works fine, too.
> >Just how would that hold the tyre to the bead wires?
> 
> Oh, fair point. Thought it was the usual boot discussion. Of course I
> have duct tape on serious touring, but that does preclude using the
> relevant brake...

No - you wrap it around the tyre, not the rim.

Matt  wrote:

> Cycling home the other evening I suddenly experienced a front tyre 
> deflation.  This is partcularly un nerving on the bent and even more so when
> you're in the feeder lane on to the A3!
> 
> Still made it to the verge to rectify what I assumed was just a normal
> puncture caused by road debris.
> 
> When I removed the tyre I found a long strand of thin metal wire had come
> lose inside the tyre and the end of this had punctured the tube.  At first I
> thought that somehow this wire had worked its way into the tyre from the
> road - although a couple of seconds thought made me realise how ridiculous
> this was.  What appears to have happened is the metal strengthening in the
> bead of the tyre had become uncovered.  I am naive enough to not even
> realise cycle tyres had steel beads!
> 
> I've not used a lot of Schwalbe tyres but this seems a very unusual failure.
> Has anyone elese experienced this sort of thing with a Schwalbe or any other
> make?
> 
> It proved quite tricky to break the wire so as I could replace the tyre and
> minimise the risk of re puncture from a sharp wire stub.  Unfortunately I
> didn't think to photograph the failure in all its glory.
> 
> I'm guessing the tyre is useless now so have ordered another.
> 
> 
> Matt
> 
> By the way no less than 4 cyclists passing by my stricken machine checked I
> was OK - one even offered me a spare tube.  Restores your faith.... 

had a punture on friday, on the rear, marthonplus, a screw that had
pentrated though,

first in a year though.

but my word the tire is so beaten up, parts of the bead and the side
wall look pritty bad, the bike is very heavy, 50lb by time all my gear
is added and the sit up and beg postion, the rear's side wall takes a
pounding...

roger
-- 
www.rogermerriman.com

On 2008-08-30, Roger Merriman  wrote:
[...]
> had a punture on friday, on the rear, marthonplus, a screw that had
> pentrated though,

That's a real coincidence-- I had exactly the same puncture also on
Friday. Marathon plus, and a nasty little 1cm long self-tapping screw
that appeared to have tapped itself into the tyre.

I actually unscrewed it with a Philips head screwdriver to get it out.
But I got it while riding so it can't have been screwed in manually by
some malicious bastard.

Ben C  wrote:

> On 2008-08-30, Roger Merriman  wrote:
> [...]
> > had a punture on friday, on the rear, marthonplus, a screw that had
> > pentrated though,
> 
> That's a real coincidence-- I had exactly the same puncture also on
> Friday. Marathon plus, and a nasty little 1cm long self-tapping screw
> that appeared to have tapped itself into the tyre.
> 
where abouts? i picked it up twickenham/st margarets, i noticed after
that, i saw some others around...

> I actually unscrewed it with a Philips head screwdriver to get it out.
> But I got it while riding so it can't have been screwed in manually by
> some malicious bastard.

that though did ocour, it has to be said.

roger
-- 
www.rogermerriman.com

On 2008-08-30, Roger Merriman  wrote:
> Ben C  wrote:
>
>> On 2008-08-30, Roger Merriman  wrote:
>> [...]
>> > had a punture on friday, on the rear, marthonplus, a screw that had
>> > pentrated though,
>> 
>> That's a real coincidence-- I had exactly the same puncture also on
>> Friday. Marathon plus, and a nasty little 1cm long self-tapping screw
>> that appeared to have tapped itself into the tyre.
>> 
> where abouts?

Cambridge.

The good news though is that the tyre went back on the rim easily. When
it was new it was very difficult to get on and I thought it had better
be "unplatbar" because I'm not going to enjoy changing it by the side of
the road in the rain.

But after it had been on there for a couple of years it seemed to have
softened up quite a bit.

Roger Merriman wrote:
> but my word the tire is so beaten up, parts of the bead and the side
> wall look pritty bad, the bike is very heavy, 50lb by time all my gear
> is added and the sit up and beg postion, the rear's side wall takes a
> pounding...

What size is the tyre, and what pressure do you inflate it to?

Under-inflation will cause durability problems with any tyre.

~PB

Pete Biggs  wrote:

> Roger Merriman wrote:
> > but my word the tire is so beaten up, parts of the bead and the side
> > wall look pritty bad, the bike is very heavy, 50lb by time all my gear
> > is added and the sit up and beg postion, the rear's side wall takes a
> > pounding...
> 
> What size is the tyre, and what pressure do you inflate it to?
> 
> Under-inflation will cause durability problems with any tyre.
> 
> ~PB 

38mm and 80psi, it's just the loads that the tire is subjected to, the
bike is very heavy, plus all my gear, with a sit up and beg postion. so
all the weight in all weathers on the rear tire.

in that time i've gone though a few rear wheels, so the tire is doing
well.

roger
-- 
www.rogermerriman.com

Ben C  wrote:

> On 2008-08-30, Roger Merriman  wrote:
> > Ben C  wrote:
> >
> >> On 2008-08-30, Roger Merriman  wrote:
> >> [...]
> >> > had a punture on friday, on the rear, marthonplus, a screw that had
> >> > pentrated though,
> >> 
> >> That's a real coincidence-- I had exactly the same puncture also on
> >> Friday. Marathon plus, and a nasty little 1cm long self-tapping screw
> >> that appeared to have tapped itself into the tyre.
> >> 
> > where abouts?
> 
> Cambridge.
> 
> The good news though is that the tyre went back on the rim easily. When
> it was new it was very difficult to get on and I thought it had better
> be "unplatbar" because I'm not going to enjoy changing it by the side of
> the road in the rain.
> 
> But after it had been on there for a couple of years it seemed to have
> softened up quite a bit.

was nice and sunny here so i just sat and changed the tube, came of
fairly easly, and back on, at least with some nice tought steel tire
levers.

roger
-- 
www.rogermerriman.com

Roger Merriman wrote:
> Pete Biggs  wrote:
>
>> Roger Merriman wrote:
>>> but my word the tire is so beaten up, parts of the bead and the side
>>> wall look pritty bad, the bike is very heavy, 50lb by time all my
>>> gear is added and the sit up and beg postion, the rear's side wall
>>> takes a pounding...
>>
>> What size is the tyre, and what pressure do you inflate it to?
>>
>> Under-inflation will cause durability problems with any tyre.
>>
>> ~PB
>
> 38mm and 80psi, it's just the loads that the tire is subjected to, the
> bike is very heavy, plus all my gear, with a sit up and beg postion.
> so all the weight in all weathers on the rear tire.
>
> in that time i've gone though a few rear wheels, so the tire is doing
> well.

The weight is irrelevant when the tyre is pumped up hard enough.  38mm @ 80 
psi should be enough, though, so I don't know why you're having the 
problems.  M+ is normally a very tough durable tyre.  I happen to know 
someone also uses these tyres with a sit up and beg position and a hell of a 
lot of weight - without problems.

~PB

Pete Biggs  wrote:

> Roger Merriman wrote:
> > Pete Biggs  wrote:
> >
> >> Roger Merriman wrote:
> >>> but my word the tire is so beaten up, parts of the bead and the side
> >>> wall look pritty bad, the bike is very heavy, 50lb by time all my
> >>> gear is added and the sit up and beg postion, the rear's side wall
> >>> takes a pounding...
> >>
> >> What size is the tyre, and what pressure do you inflate it to?
> >>
> >> Under-inflation will cause durability problems with any tyre.
> >>
> >> ~PB
> >
> > 38mm and 80psi, it's just the loads that the tire is subjected to, the
> > bike is very heavy, plus all my gear, with a sit up and beg postion.
> > so all the weight in all weathers on the rear tire.
> >
> > in that time i've gone though a few rear wheels, so the tire is doing
> > well.
> 
> The weight is irrelevant when the tyre is pumped up hard enough.  38mm @ 80
> psi should be enough, though, so I don't know why you're having the 
> problems.  M+ is normally a very tough durable tyre.  I happen to know
> someone also uses these tyres with a sit up and beg position and a hell of a
> lot of weight - without problems.
> 
> ~PB 

maybe they are slower less distance? my partners bike of simular though
not as heavy, tires are fine.

i can don't tend to slow for potholes/speedbumps etc, quite happy to use
the odd bridleway if it connects, ie i'm fairly hard on the bike. it was
intended as a simple knock about town, but it gets use a lot more heavly
than that.

even at 80psi there will be a fair amount of give, i had some simular
sized landcruisers which pinchflatted all the time, as the sidewalls
just didn't have the support.

ie the bike is workhorse so gets some horrible treatment...

roger
-- 
www.rogermerriman.com

Roger Merriman wrote:
> i can don't tend to slow for potholes/speedbumps etc, quite happy to
> use the odd bridleway if it connects, ie i'm fairly hard on the bike.
> it was intended as a simple knock about town, but it gets use a lot
> more heavly than that.

Perhaps the sidewalls are coming into contact with some of the rough stuff 
you ride.  That can happen.  Otherwise, I reckon the air should protect them 
from damage.

> even at 80psi there will be a fair amount of give, i had some simular
> sized landcruisers which pinchflatted all the time, as the sidewalls
> just didn't have the support.

Again, air pressure should prevent pinch-flats (there needs to be some give, 
but not too much).  I don't know of a bicycle tyre that has enough 
enforcement to prevent pinch-flats when the pressure is low.  (Tubeless 
tyres are used by mountain bikers using very low pressure).

~PB

Pete Biggs  wrote:

> Roger Merriman wrote:
> > i can don't tend to slow for potholes/speedbumps etc, quite happy to
> > use the odd bridleway if it connects, ie i'm fairly hard on the bike.
> > it was intended as a simple knock about town, but it gets use a lot
> > more heavly than that.
> 
> Perhaps the sidewalls are coming into contact with some of the rough stuff
> you ride.  That can happen.  Otherwise, I reckon the air should protect them
> from damage.

i think it's just the flexing the tire takes rather than being grazed.
> 
> > even at 80psi there will be a fair amount of give, i had some simular
> > sized landcruisers which pinchflatted all the time, as the sidewalls
> > just didn't have the support.
> 
> Again, air pressure should prevent pinch-flats (there needs to be some give,
> but not too much).  I don't know of a bicycle tyre that has enough 
> enforcement to prevent pinch-flats when the pressure is low.  (Tubeless
> tyres are used by mountain bikers using very low pressure).
> 
> ~PB 

even at high pressures, hit something, big enought or fast enought and
if the the sidewalls aren't robust enought the tire will pinch flat.

roger
-- 
www.rogermerriman.com

Roger Merriman wrote:
> Pete Biggs  wrote:
>
>> Roger Merriman wrote:
>>> i can don't tend to slow for potholes/speedbumps etc, quite happy to
>>> use the odd bridleway if it connects, ie i'm fairly hard on the
>>> bike. it was intended as a simple knock about town, but it gets use
>>> a lot more heavly than that.
>>
>> Perhaps the sidewalls are coming into contact with some of the rough
>> stuff you ride.  That can happen.  Otherwise, I reckon the air
>> should protect them from damage.
>
> i think it's just the flexing the tire takes rather than being grazed.

Maybe, though I'm not sure the extra flexing caused by bumps in the ground 
is ever in the same league as the flexing an under-inflated tyre gets even 
on a perfectly smooth road - when there is excessive flexing continually as 
the wheel turns with weight on it.

>>> even at 80psi there will be a fair amount of give, i had some
>>> simular sized landcruisers which pinchflatted all the time, as the
>>> sidewalls just didn't have the support.
>>
>> Again, air pressure should prevent pinch-flats (there needs to be
>> some give, but not too much).  I don't know of a bicycle tyre that
>> has enough enforcement to prevent pinch-flats when the pressure is
>> low.  (Tubeless tyres are used by mountain bikers using very low
>> pressure).
>
> even at high pressures, hit something, big enought or fast enought and
> if the the sidewalls aren't robust enought the tire will pinch flat.

A pinch flat happens when the tyre completely compresses.  You can prevent 
that ever happening by using very high pressure.  No pneumatic bicycle tyre 
I've ever seen or heard of will have robust enough sidewalls to prevent 
pinch flats.  It's air pressure alone that does that job.

I've used tyres with delicate sidewalls that have survived potholes that 
were bad enough to chuck me off the bike.  The tyres remained undamaged and 
inflated.

~PB

Pete Biggs  wrote:

> Roger Merriman wrote:
> > Pete Biggs  wrote:
> >
> >> Roger Merriman wrote:
> >>> i can don't tend to slow for potholes/speedbumps etc, quite happy to
> >>> use the odd bridleway if it connects, ie i'm fairly hard on the
> >>> bike. it was intended as a simple knock about town, but it gets use
> >>> a lot more heavly than that.
> >>
> >> Perhaps the sidewalls are coming into contact with some of the rough
> >> stuff you ride.  That can happen.  Otherwise, I reckon the air
> >> should protect them from damage.
> >
> > i think it's just the flexing the tire takes rather than being grazed.
> 
> Maybe, though I'm not sure the extra flexing caused by bumps in the ground
> is ever in the same league as the flexing an under-inflated tyre gets even
> on a perfectly smooth road - when there is excessive flexing continually as
> the wheel turns with weight on it.
> 
no but the tire is year old so not as if it's failing that quickly,
considering the weight and loads the rear takes it's not that
susprising.

> >>> even at 80psi there will be a fair amount of give, i had some
> >>> simular sized landcruisers which pinchflatted all the time, as the
> >>> sidewalls just didn't have the support.
> >>
> >> Again, air pressure should prevent pinch-flats (there needs to be
> >> some give, but not too much).  I don't know of a bicycle tyre that
> >> has enough enforcement to prevent pinch-flats when the pressure is
> >> low.  (Tubeless tyres are used by mountain bikers using very low
> >> pressure).
> >
> > even at high pressures, hit something, big enought or fast enought and
> > if the the sidewalls aren't robust enought the tire will pinch flat.
> 
> A pinch flat happens when the tyre completely compresses.  You can prevent
> that ever happening by using very high pressure.  No pneumatic bicycle tyre
> I've ever seen or heard of will have robust enough sidewalls to prevent
> pinch flats.  It's air pressure alone that does that job.
> 
er no, side walls are the real battle ground between duriblity and
weight,

no they can not do it on there own, but the stiffness of the side wall
has a real differnce, on the work horse, one could pinch flat, the rear
with the land cruisers where as you'd have a job with the marthon
pluses, same sorts of pressures 80 psi or higher, and big wide road
tires, but the marthon's have much more substantal sidewalls.

> I've used tyres with delicate sidewalls that have survived potholes that
> were bad enough to chuck me off the bike.  The tyres remained undamaged and
> inflated.
> 
you don't need a big pot hole etc just something edged to pinch the
tire.

> ~PB 

roger
-- 
www.rogermerriman.com

Roger Merriman wrote:

>> A pinch flat happens when the tyre completely compresses.  You can
>> prevent that ever happening by using very high pressure.  No
>> pneumatic bicycle tyre I've ever seen or heard of will have robust
>> enough sidewalls to prevent pinch flats.  It's air pressure alone
>> that does that job.
>>
> er no, side walls are the real battle ground between duriblity and
> weight,

I'm not taking about the durability of the sidewall here, only what 
difference it makes to pinching while it is still intact.

> no they can not do it on there own, but the stiffness of the side wall
> has a real differnce,

I would not use lower pressure because I had more sustantial sidewalls.  I 
don't believe sidewalls help enough in that way.

The resistance to pinching that the pressurised air provides is very many 
times higher than anything the tyre material is doing.

> on the work horse, one could pinch flat, the
> rear with the land cruisers where as you'd have a job with the marthon
> pluses, same sorts of pressures 80 psi or higher, and big wide road
> tires, but the marthon's have much more substantal sidewalls.
>
>> I've used tyres with delicate sidewalls that have survived potholes
>> that were bad enough to chuck me off the bike.  The tyres remained
>> undamaged and inflated.
>>
> you don't need a big pot hole etc just something edged to pinch the
> tire.

The "potholes" I referred to had square edges - a classic cause of 
pinch-flats.

You can use air pressure high enough to prevent the tyre from *ever* 
pinch-flatting.  It's just a question of whether you can stand the ride.

~PB

Pete Biggs  wrote:

> Roger Merriman wrote:
> 
> >> A pinch flat happens when the tyre completely compresses.  You can
> >> prevent that ever happening by using very high pressure.  No
> >> pneumatic bicycle tyre I've ever seen or heard of will have robust
> >> enough sidewalls to prevent pinch flats.  It's air pressure alone
> >> that does that job.
> >>
> > er no, side walls are the real battle ground between duriblity and
> > weight,
> 
> I'm not taking about the durability of the sidewall here, only what 
> difference it makes to pinching while it is still intact.
> 
> > no they can not do it on there own, but the stiffness of the side wall
> > has a real differnce,
> 
> I would not use lower pressure because I had more sustantial sidewalls.  I
> don't believe sidewalls help enough in that way.
> 
> The resistance to pinching that the pressurised air provides is very many
> times higher than anything the tyre material is doing.

sometimes you need both, yes on old red, nice light tires cope fine, no
problems but with the workhorse, even pumping a fair wack over the max
still resulted in the odd pinch flat, marthon pluses for the same give
or take air volume don't

at extreme look at jumpbikes massivly reforced sidewalls to stop the
tires popping.
> 
> > on the work horse, one could pinch flat, the
> > rear with the land cruisers where as you'd have a job with the marthon
> > pluses, same sorts of pressures 80 psi or higher, and big wide road
> > tires, but the marthon's have much more substantal sidewalls.
> >
> >> I've used tyres with delicate sidewalls that have survived potholes
> >> that were bad enough to chuck me off the bike.  The tyres remained
> >> undamaged and inflated.
> >>
> > you don't need a big pot hole etc just something edged to pinch the
> > tire.
> 
> The "potholes" I referred to had square edges - a classic cause of 
> pinch-flats.
> 
> You can use air pressure high enough to prevent the tyre from *ever* 
> pinch-flatting.  It's just a question of whether you can stand the ride.
> 
as i tend to at least with the workhorse run at the max prssure or
above, yet can still or rather used to get pinch flats with fairly wide
tires.

> ~PB 

roger
-- 
www.rogermerriman.com

Roger Merriman wrote:

> at extreme look at jumpbikes massivly reforced sidewalls to stop the
> tires popping.

Those have to be *massively* reinforced to get the significant extra 
protection.  With M+ and any more ordinary bike tyre, you can tell from 
manipulating the sidewalls with your fingers that they can't possibly put up 
much resistance.  It's nothing compared to the forces from the weight and 
bumps.

> as i tend to at least with the workhorse run at the max prssure or
> above, yet can still or rather used to get pinch flats with fairly
> wide tires.

I'm still skeptical that your differing experience was anything to do with 
the amount protection that the tyres themselves provided.  I'm thinking 
maybe they were actually inflated differently, or it was just coincidence.

~PB

Pete Biggs  wrote:

> Roger Merriman wrote:
> 
> > at extreme look at jumpbikes massivly reforced sidewalls to stop the
> > tires popping.
> 
> Those have to be *massively* reinforced to get the significant extra 
> protection.  With M+ and any more ordinary bike tyre, you can tell from
> manipulating the sidewalls with your fingers that they can't possibly put up
> much resistance.  It's nothing compared to the forces from the weight and
> bumps.

the marthon's are fairly well reforced at least compared to the cheaper
tires i had on before, nothing like jump tires though which are all
about the sidewall.
> 
> > as i tend to at least with the workhorse run at the max prssure or
> > above, yet can still or rather used to get pinch flats with fairly
> > wide tires.
> 
> I'm still skeptical that your differing experience was anything to do with
> the amount protection that the tyres themselves provided.  I'm thinking
> maybe they were actually inflated differently, or it was just coincidence.
> 
> ~PB

i kept the land cruisers for a while and upped the pressures to 100PSI
from the max psi of 65PSI but it still got the odd pinch flats, with the
marthon + at a lower PSI of 80 or lower i've never had a pinch flat.

roger
-- 
www.rogermerriman.com

Roger Merriman wrote:

> the marthon's are fairly well reforced at least compared to the
> cheaper tires i had on before, nothing like jump tires though which
> are all about the sidewall.

A pinch flat happens when the tyre gets completely compressed.

Feel how easy it is to completely compress the tyre when it is uninflated. 
Compare it to the inflated tyre and think how many times harder it is.  The 
difference in resistance between the M+'s sidewalls and the skinniest 
sidewalls possible is dwarfed by the tremendous force of the compressed air.

>> I'm still skeptical that your differing experience was anything to
>> do with the amount protection that the tyres themselves provided.
>> I'm thinking maybe they were actually inflated differently, or it
>> was just coincidence.

> i kept the land cruisers for a while and upped the pressures to 100PSI
> from the max psi of 65PSI but it still got the odd pinch flats, with
> the marthon + at a lower PSI of 80 or lower i've never had a pinch
> flat.

Something funny was going on to get pinch flats (if that's what they were) 
with wide tyres at 100 psi, and it was nothing to do with the sidewall, 
IMHO.

Sometimes a problem with the rim or rim tape can cause a puncture that looks 
like a pinch-flat.  Or you may be riding differently now, or having better 
luck with what you don't hit.

~PB

Pete Biggs  wrote:

> Roger Merriman wrote:
> 
> > the marthon's are fairly well reforced at least compared to the
> > cheaper tires i had on before, nothing like jump tires though which
> > are all about the sidewall.
> 
> A pinch flat happens when the tyre gets completely compressed.
> 
> Feel how easy it is to completely compress the tyre when it is uninflated.
> Compare it to the inflated tyre and think how many times harder it is.  The
> difference in resistance between the M+'s sidewalls and the skinniest
> sidewalls possible is dwarfed by the tremendous force of the compressed air.
> 
lots of companies would disagree, since a fair number produce tires with
reforced sidewalls, from MTB to BMX and all between, and around.

we are not talking 200PSI here but 80PSI most tires have a bit of give
at that pressure,

marthons compared to some tires give a much harsher ride, for given
pressure, compared to the three types of tires on before the Marthon
pluses are harsh, not just I rereviews it comes up.

> >> I'm still skeptical that your differing experience was anything to
> >> do with the amount protection that the tyres themselves provided.
> >> I'm thinking maybe they were actually inflated differently, or it
> >> was just coincidence.
> 
> > i kept the land cruisers for a while and upped the pressures to 100PSI
> > from the max psi of 65PSI but it still got the odd pinch flats, with
> > the marthon + at a lower PSI of 80 or lower i've never had a pinch
> > flat.
> 
> Something funny was going on to get pinch flats (if that's what they were)
> with wide tyres at 100 psi, and it was nothing to do with the sidewall,
> IMHO.
> 
as almost all my weight is on the rear, with all the gear in the paniers
the bike is 50lb unlaided, i don't hang about nor care too much with
that bike as to speed bumps etc, even with the pluses you can feel a
fair amount of give as the tire deflects a bit, i'm fairly brutish to
that bike as it's the work horse, it gets the job done.

> Sometimes a problem with the rim or rim tape can cause a puncture that looks
> like a pinch-flat.  Or you may be riding differently now, or having better
> luck with what you don't hit.
> 
unlikely as I feel the rim hit, much as one would pre suspention going
though rock gardens if you fluffed your line.

> ~PB 

roger
-- 
www.rogermerriman.com

Roger Merriman wrote:

>> A pinch flat happens when the tyre gets completely compressed.
>>
>> Feel how easy it is to completely compress the tyre when it is
>> uninflated. Compare it to the inflated tyre and think how many times
>> harder it is.  The difference in resistance between the M+'s
>> sidewalls and the skinniest sidewalls possible is dwarfed by the
>> tremendous force of the compressed air.
>>
> lots of companies would disagree, since a fair number produce tires
> with reforced sidewalls, from MTB to BMX and all between, and around.

Except in special cases for special bikes, sidewalls are reinforced to make 
the sidwalls more durable, not to make the tyre more pinch-flat resistant. 
Skinwalls are prone to getting cut and split.

> we are not talking 200PSI here but 80PSI most tires have a bit of give
> at that pressure,

Of course there is give, but it takes many more times the force to get that 
give (compress the air) than it takes to compress the sidewalls.  Try 
completely compressing your tyres at 80 psi with your fingers (you won't be 
able to).  Now try at 0 psi (you will be able to easily).  Note the huge 
difference.

That alone should prove to you that the sidewalls can do hardly anything to 
prevent pinch flats.  The force from your fingers is nothing compared to the 
force of hitting a bump with your weight on the bike.

> marthons compared to some tires give a much harsher ride, for given
> pressure, compared to the three types of tires on before the Marthon
> pluses are harsh, not just I rereviews it comes up.

The whole tyre material, not just the sidewalls, contributes to rolling 
resisance and how harsh a tyre feels.  M+ has an unusually thick layer under 
the tread.  But still it's very little compared to the resistance from 
compressed air.

I didn't notice very much difference anyway when comparing M+ to Specialzed 
Nimbus EX.  (Same bike, same size tyres, same pressure).  The Nimbuses have 
skinny sidewalls.

>>>> I'm still skeptical that your differing experience was anything to
>>>> do with the amount protection that the tyres themselves provided.
>>>> I'm thinking maybe they were actually inflated differently, or it
>>>> was just coincidence.
>>
>>> i kept the land cruisers for a while and upped the pressures to
>>> 100PSI from the max psi of 65PSI but it still got the odd pinch
>>> flats, with the marthon + at a lower PSI of 80 or lower i've never
>>> had a pinch flat.
>>
>> Something funny was going on to get pinch flats (if that's what they
>> were) with wide tyres at 100 psi, and it was nothing to do with the
>> sidewall, IMHO.
>>
> as almost all my weight is on the rear, with all the gear in the
> paniers the bike is 50lb unlaided, i don't hang about nor care too
> much with that bike as to speed bumps etc, even with the pluses you
> can feel a fair amount of give as the tire deflects a bit, i'm fairly
> brutish to that bike as it's the work horse, it gets the job done.
>
>> Sometimes a problem with the rim or rim tape can cause a puncture
>> that looks like a pinch-flat.  Or you may be riding differently now,
>> or having better luck with what you don't hit.
>>
> unlikely as I feel the rim hit, much as one would pre suspention going
> though rock gardens if you fluffed your line.

A big impact with a hard tyre can feel lke the rim is hitting when it 
actually isn't.  But if the rim really is hitting then you need even higher 
pressure.  +10 psi will make far more difference than that from different 
sidewalls.

I feel sorry for your wheels! :-)

~PB

Pete Biggs  wrote:

> Roger Merriman wrote:
> 
> >> A pinch flat happens when the tyre gets completely compressed.
> >>
> >> Feel how easy it is to completely compress the tyre when it is
> >> uninflated. Compare it to the inflated tyre and think how many times
> >> harder it is.  The difference in resistance between the M+'s
> >> sidewalls and the skinniest sidewalls possible is dwarfed by the
> >> tremendous force of the compressed air.
> >>
> > lots of companies would disagree, since a fair number produce tires
> > with reforced sidewalls, from MTB to BMX and all between, and around.
> 
> Except in special cases for special bikes, sidewalls are reinforced to make
> the sidwalls more durable, not to make the tyre more pinch-flat resistant.
> Skinwalls are prone to getting cut and split.
> 
some are, some are talking about pinch flats.

> > we are not talking 200PSI here but 80PSI most tires have a bit of give
> > at that pressure,
> 
> Of course there is give, but it takes many more times the force to get that
> give (compress the air) than it takes to compress the sidewalls.  Try
> completely compressing your tyres at 80 psi with your fingers (you won't be
> able to).  Now try at 0 psi (you will be able to easily).  Note the huge
> difference.
> 
> That alone should prove to you that the sidewalls can do hardly anything to
> prevent pinch flats.  The force from your fingers is nothing compared to the
> force of hitting a bump with your weight on the bike.
> 
> > marthons compared to some tires give a much harsher ride, for given
> > pressure, compared to the three types of tires on before the Marthon
> > pluses are harsh, not just I rereviews it comes up.
> 
> The whole tyre material, not just the sidewalls, contributes to rolling
> resisance and how harsh a tyre feels.  M+ has an unusually thick layer under
> the tread.  But still it's very little compared to the resistance from
> compressed air.
> 
i don't think the plus feel much differnet to the standard which i have
on another bike and feels equally fairly harsh.

> I didn't notice very much difference anyway when comparing M+ to Specialzed
> Nimbus EX.  (Same bike, same size tyres, same pressure).  The Nimbuses have
> skinny sidewalls.

what sizes? rember i'm talking ballon tires really, 35-38mm i noticed
quite a lot of differance between the various tires i've had on there.
> 
> >>>> I'm still skeptical that your differing experience was anything to
> >>>> do with the amount protection that the tyres themselves provided.
> >>>> I'm thinking maybe they were actually inflated differently, or it
> >>>> was just coincidence.
> >>
> >>> i kept the land cruisers for a while and upped the pressures to
> >>> 100PSI from the max psi of 65PSI but it still got the odd pinch
> >>> flats, with the marthon + at a lower PSI of 80 or lower i've never
> >>> had a pinch flat.
> >>
> >> Something funny was going on to get pinch flats (if that's what they
> >> were) with wide tyres at 100 psi, and it was nothing to do with the
> >> sidewall, IMHO.
> >>
> > as almost all my weight is on the rear, with all the gear in the
> > paniers the bike is 50lb unlaided, i don't hang about nor care too
> > much with that bike as to speed bumps etc, even with the pluses you
> > can feel a fair amount of give as the tire deflects a bit, i'm fairly
> > brutish to that bike as it's the work horse, it gets the job done.
> >
> >> Sometimes a problem with the rim or rim tape can cause a puncture
> >> that looks like a pinch-flat.  Or you may be riding differently now,
> >> or having better luck with what you don't hit.
> >>
> > unlikely as I feel the rim hit, much as one would pre suspention going
> > though rock gardens if you fluffed your line.
> 
> A big impact with a hard tyre can feel lke the rim is hitting when it
> actually isn't.  But if the rim really is hitting then you need even higher
> pressure.  +10 psi will make far more difference than that from different
> sidewalls.
> 
same "oof" but if you bottom out you'll feel the rim touch down, and
think oh shoot or what ever.

with the marthons i can feel the tire bulge under the load but it
doesn't attaully bottom out.

> I feel sorry for your wheels! :-)
> 
you should do the rears last no time at all, few months maybe then the
hubs give out, get to the point where i have two wheel stearing...

> ~PB 

roger
-- 
www.rogermerriman.com

Roger Merriman wrote:

>> Except in special cases for special bikes, sidewalls are reinforced
>> to make the sidwalls more durable, not to make the tyre more
>> pinch-flat resistant. Skinwalls are prone to getting cut and split.
>>
> some are, some are talking about pinch flats.

They might be talking BS - which wouldn't be an unusual thing for a tyre 
manufacturer to do.

>> I didn't notice very much difference anyway when comparing M+ to
>> Specialzed Nimbus EX.  (Same bike, same size tyres, same pressure).
>> The Nimbuses have skinny sidewalls.
>
> what sizes? rember i'm talking ballon tires really, 35-38mm i noticed
> quite a lot of differance between the various tires i've had on there.

Same here, 38mm.  Not on one of my own bikes, to be fair, so I haven't 
ridden it a great deal, but one I do the odd job on.  In fact I'll be 
fitting a new wheel to it soon and transfering the tyre, so I'll remind 
myself what the M+ sidewalls feel like.  I don't remember them being much 
out of the ordinary.

~PB

On Sep 9, 2:23 am, "Pete Biggs"
 wrote:
> Roger Merriman wrote:
> >> Except in special cases for special bikes, sidewalls are reinforced
> >> to make the sidwalls more durable, not to make the tyre more
> >> pinch-flat resistant. Skinwalls are prone to getting cut and split.
>
> > some are, some are talking about pinch flats.
>
> They might be talking BS - which wouldn't be an unusual thing for a tyre
> manufacturer to do.

While I am agnostic about the value of tougher sidewalls for pinch
flats, it should be noted that the pinch requires not only that the
walls are pushed together, but that the pressure between them is high
enough to cut through the inner tube. It seems plausible that a
thicker sidewall might help with this by spreading out the pressure
point, blunting the impact a bit.

James

james.annan@gmail.com wrote:

> While I am agnostic about the value of tougher sidewalls for pinch
> flats, it should be noted that the pinch requires not only that the
> walls are pushed together, but that the pressure between them is high
> enough to cut through the inner tube. It seems plausible that a
> thicker sidewall might help with this by spreading out the pressure
> point, blunting the impact a bit.

Interesting point, thanks very much.

Perhaps that does happen a tiny bit.  The rest of the tyre may also cushion 
the blow - probably to a greater extent with the Marathon Plus that 
unusually has a large amount of padding under the tread.  So Roger may be 
right afterall that you get fewer pinch flats with it than with lighter 
tyres - but for a reason we hadn't thought of!

However, I would not ever want the tyre to fully compress anyway.  I want a 
good margin of air always to make sure the rim is well protected.  Fixing a 
puncture is trivial compared to fixing or replacing a wheel.  The tyre may 
help to prevent the tube puncturing, but still the tyre itself, like nearly 
all bicycle tyres, pinches flat easily when there is not enough air 
pressure.

~PB

Roger Merriman wrote:

> rember i'm talking ballon tires really, 35-38mm i noticed
> quite a lot of differance between the various tires i've had on there.

Were your previous tyres 35mm and your current ones 38mm?  35mm tyres need 
more psi to get the same protection.

> with the marthons i can feel the tire bulge under the load but it
> doesn't attaully bottom out.

It will bottom out just as easily as any other tyre (I can do it with my 
fingers when uninflated), but perhaps the thick padding under the tread 
makes it feel as if it isn't.

>> I feel sorry for your wheels! :-)
>>
> you should do the rears last no time at all, few months maybe then the
> hubs give out, get to the point where i have two wheel stearing...

Boringly, I would ride more carefullly!

~PB

On Mon, 8 Sep 2008, Pete Biggs wrote:

> Roger Merriman wrote:
>
>>> Except in special cases for special bikes, sidewalls are reinforced to 
>>> make the sidwalls more durable, not to make the tyre more pinch-flat 
>>> resistant. Skinwalls are prone to getting cut and split.
>>
>> some are, some are talking about pinch flats.
>
> They might be talking BS - which wouldn't be an unusual thing for a tyre 
> manufacturer to do.

Really? I would have thought they'd be more likely to be talking DIN.

:)

tom

-- 
Baby got a masterplan. A foolproof masterplan.

On Tue, 9 Sep 2008 23:06:44 +0100
Tom Anderson  wrote:

> On Mon, 8 Sep 2008, Pete Biggs wrote:
are, some are talking about pinch flats.
> >
> > They might be talking BS - which wouldn't be an unusual thing for a
> > tyre manufacturer to do.
> 
> Really? I would have thought they'd be more likely to be talking DIN.
> 
Is that your coat by the door?  :-)

On Wed, 10 Sep 2008, Rob Morley wrote:

> On Tue, 9 Sep 2008 23:06:44 +0100
> Tom Anderson  wrote:
>
>> On Mon, 8 Sep 2008, Pete Biggs wrote:
> are, some are talking about pinch flats.
>>
>>> They might be talking BS - which wouldn't be an unusual thing for a
>>> tyre manufacturer to do.
>>
>> Really? I would have thought they'd be more likely to be talking DIN.
>
> Is that your coat by the door?  :-)

I'm here all week, folks!

tom

-- 
And dear lord, its like peaches in a lacy napkin. -- James Dearden