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:

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

"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.

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

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!

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...