persistent punctures

Ben said:

Hi

I've replaced my inner tube 5 times in the last week and
each time its had a bloody big hole in it within 24 hours.
3 of those times I haven't even taken the bike out, its
just been sitting in my house. The punctures are in a
different place each time, one of them was on the rim
side. I've just replaced the tube now and a few minutes
after putting the wheel back on the bike I can already
hear a loud hissing noise. I am at a complete loss to
understand whats going on (any suggestions gratefully
recieved) but I'm starting to suspect it might have
something to do with the fact that I'm using a different
brand of tube. Two observations;

1) Today I tried fitting the tube with a *little* more air
in it than usual just to make sure it wasn't getting
pinched, but had to let it out again because the length
of the tube increased by over a foot so it wouldn't fit
anymore. I really do mean a little air - is this
normal?

2) Because the hissing started within minutes this time, I
decided to pump up another tube from the pack without
fitting it just to see if it would fail. Before the
pressure got anywhere near 20psi it went bang. Is this
normal? (perhaps you're not supposed to do this)

Is the rim tape allowing the tube to expand into one of the
spoke holes?

Ben said:

2) Because the hissing started within minutes this time, I
decided to pump up another tube from the pack without
fitting it just to see if it would fail. Before the
pressure got anywhere near 20psi it went bang. Is this
normal? (perhaps you're not supposed to do this)

Different parts of the tube stretch different amounts (e.g.
the area around the valve probably doesn't stretch much at
all). If you pump it up so far that it grows bigger than it
would do inside the tyre, then yes, I'd expect it won't do
the tube much good.

-dan

--
"please make sure that the person is your friend before
you confirm"

Ben said:

I've replaced my inner tube 5 times in the last week and
each time its had a bloody big hole in it within 24 hours.
3 of those times I haven't even taken the bike out, its
just been sitting in my house. The punctures are in a
different place each time, one of them was on the rim
side. I've just replaced the tube now and a few minutes
after putting the wheel back on the bike I can already
hear a loud hissing noise. I am at a complete loss to
understand whats going on (any suggestions gratefully
recieved) but I'm starting to suspect it might have
something to do with the fact that I'm using a different
brand of tube. Two observations;

1) Today I tried fitting the tube with a *little* more air
in it than usual just to make sure it wasn't getting
pinched, but had to let it out again because the length
of the tube increased by over a foot so it wouldn't fit
anymore. I really do mean a little air - is this
normal?

Yes. The tube will go on expanding until it explodes if it
is not contained within a tyre.

Quoted message said:

the hissing started within minutes this time, I decided to
pump up another tube from the pack without fitting it just
to see if it would fail. Before the pressure got anywhere
near 20psi it went bang. Is this normal? (perhaps you're
not supposed to do this)

Yes. The tube will go on expanding until it explodes if it
is not contained within a tyre. :-)

The rim tape is probably not withstanding the pressure,
especially if it's the rubber type. Try Velox cloth tape or
a plastic tape designed for high pressure.

Normally the holes would be rim-side down if rim or rim tape
was to blame but not always if tube was twisted.

~PB

A few suggestions:

1. Is the rim tape in good condition, correctly seated and
the right length?

2. Have the spokes been retentioned at some stage? If so,
some of them will be protruding through the rim and
might need to be filed down.

3. Once you've got the tube and tyre in place, inflate the
tube a little bit (5 or 10 psi) and squeeze the tyre
walls together all the way around the circumference -
this should reseat the tyre and reduce the chance of the
tube being caught between tyre bead and rim.

4. To state the bleedin' obvious, feel around the inside of
the tyre for thorns sticking through!

Hope this helps.

On your questions:

5. Over a foot? Ye gods, that does sound rather a lot! You
only need to inflate the tube enough to stop it
collapsing on itself, nothing more.

6. Yes, I'd expect a tube to explode if pressurised in the
open air - they're designed to be constrained by the
tyre and rim, so in the open air they'll stretch
waaaaaaaay too much.

Good luck!

Huw

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

Quoted message said:

Hi

I've replaced my inner tube 5 times in the last week and
each time its had a bloody big hole in it within 24 hours.
3 of those times I haven't even taken the bike out, its
just been sitting in my house. The punctures are in a
different place each time, one of them was on the rim
side. I've just replaced the tube now and a few minutes
after putting the wheel back on the bike I can already
hear a loud hissing noise. I am at a complete loss to
understand whats going on (any suggestions gratefully
recieved) but I'm starting to suspect it might have
something to do with the fact that I'm using a different
brand of tube. Two observations;

1) Today I tried fitting the tube with a *little* more air
in it than usual just to make sure it wasn't getting
pinched, but had to let it out again because the length
of the tube increased by over a foot so it wouldn't fit
anymore. I really do mean a little air - is this
normal?

2) Because the hissing started within minutes this time, I
decided to pump up another tube from the pack without
fitting it just to see if it would fail. Before the
pressure got anywhere near 20psi it went bang. Is this
normal? (perhaps you're not supposed to do this)

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

Quoted message said:

Ben said:

I've replaced my inner tube 5 times in the last week and
each time its had a bloody big hole in it within 24
hours. 3 of those times I haven't even taken the bike
out, its just been sitting in my house. The punctures
are in a different place each time, one of them was on
the rim side. I've just replaced the tube now and a few
minutes after putting the wheel back on the bike I can
already hear a loud hissing noise. I am at a complete
loss to understand whats going on (any suggestions
gratefully recieved) but I'm starting to suspect it
might have something to do with the fact that I'm using
a different brand of tube. Two observations;

1) Today I tried fitting the tube with a *little* more
air in it than usual just to make sure it wasn't
getting pinched, but had to let it out again because
the length of the tube increased by over a foot so it
wouldn't fit anymore. I really do mean a little air -
is this normal?

Yes. The tube will go on expanding until it explodes if it
is not contained within a tyre.

Quoted message said:

the hissing started within minutes this time, I decided
to pump up another tube from the pack without fitting it
just to see if it would fail. Before the pressure got
anywhere near 20psi it went bang. Is this normal?
(perhaps you're not supposed to do this)

Yes. The tube will go on expanding until it explodes if it
is not contained within a tyre. :-)

The rim tape is probably not withstanding the pressure,
especially if it's the rubber type. Try Velox cloth tape
or a plastic tape designed for high pressure.

Normally the holes would be rim-side down if rim or rim
tape was to blame but not always if tube was twisted.

~PB

=============
Since the punctures appear at different places it's quite
possible that you've got some kind of 'foreign body'
rolling about in the tyre - possibly a broken-off thorn or
something similar.

Cic.

Pete Biggs said:

Ben said:

I've replaced my inner tube 5 times in the last week and
each time its had a bloody big hole in it within 24 hours.
3 of those times I haven't even taken the bike out, its
just been sitting in my house. The punctures are in a
different place each time, one of them was on the rim
side. I've just replaced the tube now and a few minutes
after putting the wheel back on the bike I can already
hear a loud hissing noise. I am at a complete loss to
understand whats going on (any suggestions gratefully
recieved) but I'm starting to suspect it might have
something to do with the fact that I'm using a different
brand of tube. Two observations;

1) Today I tried fitting the tube with a *little* more air
in it than usual just to make sure it wasn't getting
pinched, but had to let it out again because the length
of the tube increased by over a foot so it wouldn't fit
anymore. I really do mean a little air - is this
normal?

Yes. The tube will go on expanding until it explodes if it
is not contained within a tyre.

Quoted message said:

the hissing started within minutes this time, I decided to
pump up another tube from the pack without fitting it just
to see if it would fail. Before the pressure got anywhere
near 20psi it went bang. Is this normal? (perhaps you're
not supposed to do this)

Yes. The tube will go on expanding until it explodes if it
is not contained within a tyre. :-)

The rim tape is probably not withstanding the pressure,
especially if it's the rubber type. Try Velox cloth tape
or a plastic tape designed for high pressure.

Normally the holes would be rim-side down if rim or rim
tape was to blame but not always if tube was twisted.

Sounds plausible - the punctures further round away from the
valve are more ambiguous, but the one near the valve where
the tube couldn't have been twisted was clearly on the rim
side. The rim tape is just the stuff that came with the
wheel, its black shiny plasticy looking stuff. I've been
having a lot of punctures on that wheel over the past year,
so maybe that explains it.

Vincent Wilcox said:

Ben said:

Hi

I've replaced my inner tube 5 times in the last week and
each time its had a bloody big hole in it within 24
hours. 3 of those times I haven't even taken the bike
out, its just been sitting in my house. The punctures are
in a different place each time, one of them was on the
rim side. I've just replaced the tube now and a few
minutes after putting the wheel back on the bike I can
already hear a loud hissing noise. I am at a complete
loss to understand whats going on (any suggestions
gratefully recieved) but I'm starting to suspect it might
have something to do with the fact that I'm using a
different brand of tube. Two observations;

1) Today I tried fitting the tube with a *little* more
air in it than usual just to make sure it wasn't
getting pinched, but had to let it out again because
the length of the tube increased by over a foot so it
wouldn't fit anymore. I really do mean a little air -
is this normal?

2) Because the hissing started within minutes this time,
I decided to pump up another tube from the pack
without fitting it just to see if it would fail.
Before the pressure got anywhere near 20psi it went
bang. Is this normal? (perhaps you're not supposed to
do this)

Is the rim tape allowing the tube to expand into one of
the spoke holes?

I didn't think so, but another poster has suggested this so
I think I'll try some new rim tape.

Cicero said:

Since the punctures appear at different places it's quite
possible that you've got some kind of 'foreign body'
rolling about in the tyre - possibly a broken-off thorn or
something similar.

I've checked *really* thoroughly for this each time and
never found anything, so I'm pretty confident thats not it.
However, seen as how I'm going to be having another go
tomorrow...

"Pete Biggs" <[email hidden]>typed

Quoted message said:

Ben said:

I've replaced my inner tube 5 times in the last week and
each time its had a bloody big hole in it within 24
hours.

You poor thing!

Quoted message said:

Quoted message said:

the hissing started within minutes this time, I decided
to pump up another tube from the pack without fitting it
just to see if it would fail. Before the pressure got
anywhere near 20psi it went bang. Is this normal?
(perhaps you're not supposed to do this)

It's worth checking new/repaired/unused tubes under water
before you fit them, to avoid disappointment & frustration.
Inflate until the tube is a little above the normal tyre
size, NOT HUGE and pass all of the tube, including the valve
under water (bath temperature may be more comfortable for
you), looking for bubbles. If a brand new tube bubbles, it
is faulty. Demand a refund from your supplier.

Quoted message said:

The rim tape is probably not withstanding the pressure,
especially if it's the rubber type. Try Velox cloth tape
or a plastic tape designed for high pressure.

I would echo the Velox rim tape suggestion.

I take it you aren't pinching your new tube between tyre and
rim or tools...

--
Helen D. Vecht: [email hidden] Edgware.

"Pete Biggs" <[email hidden]>typed

Quoted message said:

Ben said:

I've replaced my inner tube 5 times in the last week and
each time its had a bloody big hole in it within 24
hours.

You poor thing!

Quoted message said:

Quoted message said:

the hissing started within minutes this time, I decided
to pump up another tube from the pack without fitting it
just to see if it would fail. Before the pressure got
anywhere near 20psi it went bang. Is this normal?
(perhaps you're not supposed to do this)

It's worth checking new/repaired/unused tubes under water
before you fit them, to avoid disappointment & frustration.
Inflate until the tube is a little above the normal tyre
size, NOT HUGE and pass all of the tube, including the valve
under water (bath temperature may be more comfortable for
you), looking for bubbles. If a brand new tube bubbles, it
is faulty. Demand a refund from your supplier.

Quoted message said:

The rim tape is probably not withstanding the pressure,
especially if it's the rubber type. Try Velox cloth tape
or a plastic tape designed for high pressure.

I would echo the Velox rim tape suggestion.

I take it you aren't pinching your new tube between tyre and
rim or tools...

--
Helen D. Vecht: [email hidden] Edgware.

Huw Francis said:

A few suggestions:

1. Is the rim tape in good condition, correctly seated
and the right length?

2. Have the spokes been retentioned at some stage? If so,
some of them will be protruding through the rim and
might need to be filed down.

3. Once you've got the tube and tyre in place, inflate
the tube a little bit (5 or 10 psi) and squeeze the
tyre walls together all the way around the
circumference - this should reseat the tyre and reduce
the chance of the tube being caught between tyre bead
and rim.

4. To state the bleedin' obvious, feel around the inside
of the tyre for thorns sticking through!

Well, perhaps stating the bleedin obvious is what I need.
The last 2 punctures have been in the same place, so I had a
good look and there's a tack sticking through my tyre, one
of those short fat ones perfect for causing punctures but
apparently useless for anything else, except perhaps
upholstery, which always makes me wonder what they're doing
lying around point-upwards on the road. It can't be seen or
felt on the inside of the tyre, which is where I've been
looking and feeling, but its pretty obvious on the outside.
This doesn't explain the puncture earlier in the week that
was on the rim-side of the tube near the valve, but that one
was such a massive hole that perhaps it was a one-off
manufacturing defect. Such apparently unlikely runs of bad
luck usually turn out to be a combination of factors.

Quoted message said:

Hope this helps.

On your questions:

1. Over a foot? Ye gods, that does sound rather a lot!
You only need to inflate the tube enough to stop it
collapsing on itself, nothing more.

2. Yes, I'd expect a tube to explode if pressurised in
the open air - they're designed to be constrained by
the tyre and rim, so in the open air they'll stretch
waaaaaaaay too much.

Good luck!

Huw Francis said:

A few suggestions:

1. Is the rim tape in good condition, correctly seated
and the right length?

2. Have the spokes been retentioned at some stage? If so,
some of them will be protruding through the rim and
might need to be filed down.

3. Once you've got the tube and tyre in place, inflate
the tube a little bit (5 or 10 psi) and squeeze the
tyre walls together all the way around the
circumference - this should reseat the tyre and reduce
the chance of the tube being caught between tyre bead
and rim.

4. To state the bleedin' obvious, feel around the inside
of the tyre for thorns sticking through!

Well, perhaps stating the bleedin obvious is what I need.
The last 2 punctures have been in the same place, so I had a
good look and there's a tack sticking through my tyre, one
of those short fat ones perfect for causing punctures but
apparently useless for anything else, except perhaps
upholstery, which always makes me wonder what they're doing
lying around point-upwards on the road. It can't be seen or
felt on the inside of the tyre, which is where I've been
looking and feeling, but its pretty obvious on the outside.
This doesn't explain the puncture earlier in the week that
was on the rim-side of the tube near the valve, but that one
was such a massive hole that perhaps it was a one-off
manufacturing defect. Such apparently unlikely runs of bad
luck usually turn out to be a combination of factors.

Quoted message said:

Hope this helps.

On your questions:

1. Over a foot? Ye gods, that does sound rather a lot!
You only need to inflate the tube enough to stop it
collapsing on itself, nothing more.

2. Yes, I'd expect a tube to explode if pressurised in
the open air - they're designed to be constrained by
the tyre and rim, so in the open air they'll stretch
waaaaaaaay too much.

Good luck!

Ben said:

Cicero said:

Since the punctures appear at different places it's quite
possible that you've got some kind of 'foreign body'
rolling about in the tyre - possibly a broken-off thorn
or something similar.

I've checked *really* thoroughly for this each time and
never found anything, so I'm pretty confident thats not
it. However, seen as how I'm going to be having another go
tomorrow...

I had this once... it took me 3 weeks to find the single
strand of bowden cable that was lodged in the tyre ):

It might be worth changing the tyre? You'll need a new one
eventually!

Steve

Ben said:

Cicero said:

Since the punctures appear at different places it's quite
possible that you've got some kind of 'foreign body'
rolling about in the tyre - possibly a broken-off thorn
or something similar.

I've checked *really* thoroughly for this each time and
never found anything, so I'm pretty confident thats not
it. However, seen as how I'm going to be having another go
tomorrow...

I had this once... it took me 3 weeks to find the single
strand of bowden cable that was lodged in the tyre ):

It might be worth changing the tyre? You'll need a new one
eventually!

Steve

Steve said:

Ben said:

Cicero said:

Since the punctures appear at different places it's
quite possible that you've got some kind of 'foreign
body' rolling about in the tyre - possibly a broken-off
thorn or something similar.

I've checked *really* thoroughly for this each time and
never found anything, so I'm pretty confident thats not
it. However, seen as how I'm going to be having another
go tomorrow...

I had this once... it took me 3 weeks to find the single
strand of bowden cable that was lodged in the tyre ):

Well, you have my sympathy now ;-)

Quoted message said:

It might be worth changing the tyre? You'll need a new one
eventually!

No chance, the tyre was brand new at the start of the week!
Anyway, I'm cautiously optimistic that the problem might be
solved for now - see my recent post.

Steve said:

Ben said:

Cicero said:

Since the punctures appear at different places it's
quite possible that you've got some kind of 'foreign
body' rolling about in the tyre - possibly a broken-off
thorn or something similar.

I've checked *really* thoroughly for this each time and
never found anything, so I'm pretty confident thats not
it. However, seen as how I'm going to be having another
go tomorrow...

I had this once... it took me 3 weeks to find the single
strand of bowden cable that was lodged in the tyre ):

Well, you have my sympathy now ;-)

Quoted message said:

It might be worth changing the tyre? You'll need a new one
eventually!

No chance, the tyre was brand new at the start of the week!
Anyway, I'm cautiously optimistic that the problem might be
solved for now - see my recent post.

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

Quoted message said:

... This doesn't explain the puncture earlier in the week
that was on the rim-side of the tube near the valve, but
that one was such a massive hole that perhaps it was a one-
off manufacturing defect.

A massive hole is most likely due to having been pinched
under the tyre bead while fitting. Tubes pinched in this way
can be hard to spot and will suddenly form a bubble and go
bang, leaving a big hole. You may not have been there at the
time to hear the bang. If a big hole had been there
immediately on installing it you would not have been able to
get a convincing amount of air into it.

--
Dave...