Explosive puncture



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Sky Fly

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Last weekend, I was out on a 50 mile ride around the Kentish countryside. Unfortunately, it was
somewhat lacking in the satisfaction department, especially because I had three punctures on the way
(it's a good thing I carried my puncture repair kit along with me). What *did* puzzle me was the
third puncture - there was a loud 'pop' sound that preceded the puncture, and when I had a look at
the inner tube, it was completely unpatchable - it had a huge longitudinal split, quite unlike the
usual small holes I get. Has anyone ever had this, and does anyone know what might have caused it?

--
Akin

aknak at aksoto dot idps dot co dot uk
 
"Sky Fly" <[email protected]> wrote in message
news:[email protected]...
> Last weekend, I was out on a 50 mile ride around the Kentish countryside. Unfortunately, it was
> somewhat lacking in the satisfaction department, especially because I had three punctures on the
> way (it's a good thing I carried my puncture repair kit along with me). What *did* puzzle me was
> the third puncture - there was a loud 'pop' sound that preceded the puncture, and when I had a
> look at the inner tube, it was completely unpatchable - it had a huge longitudinal split, quite
> unlike the usual small holes I get. Has anyone ever had this, and does anyone know what might have
> caused it?
>

It sounds like a problem with your rim, or the way you are fitting the tyres. Something internally
is catching the tube, rather than thorns etc getting through from the outside.

Check the rim for sharp edges and that the rim tape is good, Also check that the type doesn't have
any thing sticking through it. The inner tube can also get pinched between the rim and tyre when
fitting so check that this hasn't happened before pumping the tyre up fully.

Modern tyres are pretty good, three punctures a year would be more normal than three in one trip.
 
Originally posted by Sky Fly
What *did* puzzle me was the
third puncture - there was a loud 'pop' sound that preceded the puncture, and when I had a look at
the inner tube, it was completely unpatchable - it had a huge longitudinal split,

might be time for a new tyre or rim. It sounds like the tyre popped off the rim allowing the inner tube to blow itself out the hole (hence the pop and shredding). Since you don't mention it I would guess that the tyre popped back on. Inspect the tyre sidewall and rim carefully.

best wishes
james
 
"pig pog" <[email protected]> wrote in message news:[email protected]...
> Sky Fly wrote:
> > What *did* puzzle me was the third puncture - there was a loud 'pop' sound that preceded the
> > puncture, and when I had a look at the inner tube, it was completely unpatchable - it had a
> > huge longitudinal
split,
>
>
>
> might be time for a new tyre or rim. It sounds like the tyre popped off the rim allowing the inner
> tube to blow itself out the hole (hence the pop and shredding). Since you don't mention it I would
> guess that the tyre popped back on. Inspect the tyre sidewall and rim carefully.

You're probably right... one of the other things I noticed was that when riding, there was this
"bump-bump-bump" feeling which may have been caused by uneven pressure in the tyre at the point
where the tyre sidewall was weak.

I'll check it sometime later.

Thanks,

--
Akin

aknak at aksoto dot idps dot co dot uk
 
Sky Fly wrote:
> one of the other things I noticed was that when riding, there was this "bump-bump-bump" feeling
> which may have been caused by uneven pressure in the tyre at the point where the tyre sidewall
> was weak.

That sounds more like the tyre wasn't seated properly at the valve because the valve wasn't pushed
into the tyre. This creates a bump at the valve area.

~PB
 
Pete Biggs wrote:
> Sky Fly wrote:
>> one of the other things I noticed was that when riding, there was this "bump-bump-bump" feeling
>> which may have been caused by uneven pressure in the tyre at the point where the tyre sidewall
>> was weak.
>
> That sounds more like the tyre wasn't seated properly at the valve because the valve wasn't pushed
> into the tyre. This creates a bump at the valve area.
>
> ~PB

The inner tube was probably preventing the tyre from seating properly, i.e. it was nipped between
the rim and tyre, hence the slit

--
The Reply & From email addresses are checked rarely.
 
"Sky Fly" <[email protected]> wrote in message
news:<[email protected]>...

> I had three punctures on the way (it's a good thing I carried my puncture repair kit along with
> me). What *did* puzzle me was the third puncture - there was a loud 'pop' sound that preceded the
> puncture, and when I had a look at the inner tube, it was completely unpatchable - it had a huge
> longitudinal split, quite unlike the usual small holes I get. Has anyone ever had this, and does
> anyone know what might have caused it?

The tube never goes bang unless part of it is outside the tyre. The most likely thing is that when
you put the tyre on after the second puncture the tube got pinched between the it and the rim. As
you rode along the pinch formed into a bubble with the result you experienced.

A second puncture is generally quite unlucky, but if it was in the same tyre it's possible that the
object that caused the first puncture was still in the tyre waiting to cause the second one.

--
Dave...
 
Sky Fly wrote:
> Last weekend, I was out on a 50 mile ride around the Kentish countryside. Unfortunately, it was
> somewhat lacking in the satisfaction department, especially because I had three punctures on the
> way (it's a good thing I carried my puncture repair kit along with me). What *did* puzzle me was
> the third puncture - there was a loud 'pop' sound that preceded the puncture, and when I had a
> look at the inner tube, it was completely unpatchable - it had a huge longitudinal split, quite
> unlike the usual small holes I get. Has anyone ever had this, and does anyone know what might have
> caused it?

Yep. The tyre came off the rim. It often falls back on again when the tube explodes.
 
"MSeries" <[email protected]> wrote in message
news:[email protected]...
> Pete Biggs wrote:
> > Sky Fly wrote:
> >> one of the other things I noticed was that when riding, there was this "bump-bump-bump"
> >> feeling which may have been caused by uneven pressure in the tyre at the point where the tyre
> >> sidewall was weak.
> >
> > That sounds more like the tyre wasn't seated properly at the valve because the valve wasn't
> > pushed into the tyre. This creates a bump at the valve area.
> >
> > ~PB
>
> The inner tube was probably preventing the tyre from seating properly,
i.e.
> it was nipped between the rim and tyre, hence the slit

If that's the case, how do I prevent this from happening when changing tubes? When I stuff the
tube into the space between the rim and the tyre, it's a bit difficult checking what happens
from then on.
 
Sky Fly wrote:

> If that's the case, how do I prevent this from happening when changing tubes? When I stuff the
> tube into the space between the rim and the tyre, it's a bit difficult checking what happens from
> then on.

Semi inflate the tube before stuffing it in or stuff it in then semi inflate so it forms a
tubular cross section and hopefully moves away from the edge of the rim. Check the seating of the
tyre before fully inflating and remove/refit if it looks like it is not seated properly all the
way round.

Its one of those things that come with experience and is difficult to explain. I try to push the
tube into the tyre/rim with the tyre, rather than lift the tyre onto the rim. Some rims are easier
than others for this. My MA3s are complete b*****ds for fitting tyres they are so tight, yet my
Reflex ones can be fitted with just my bare hands.

--
The Reply & From email addresses are checked rarely.
 
Sky Fly wrote:
> If that's the case, how do I prevent this from happening when changing tubes? When I stuff the
> tube into the space between the rim and the tyre, it's a bit difficult checking what happens from
> then on.

Don't tighten the valve lockring (if using one) until tyre is fitted, fit the tyre leaving the bit
at the valve until last*, push the valve up into the tyre as you tuck the last bit of bead under it.
It will then stay in place and tyre will be properly seated from then on as long as the bead doesn't
pop off again whilst trying to fit.

* Not strictly necessary but it helps with this issue and also makes fitting tight tyres easier. The
other way round, on the other hand, makes valve alignment easier - this method is ok if tyres are
easy-fitting and you're careful.

~PB
 
I wrote: [on finishing at valve]
> * Not strictly necessary but it helps with this issue and also makes fitting tight tyres easier.
> The other way round, on the other hand, makes valve alignment easier - this method is ok if
> tyres are easy-fitting and you're careful.

Just to be clear, the pushing-the-valve-up bit IS strictly necessary. Although you dont' literally
have to push up and seat tyre at the same time but push the valve just before pushing sidewall in
with thumbs (valve will stay up for a few secs by itself at least if not all the while).

If you normally do all this already, you may just have been unlucky this time and missed it. Just be
extra carful in future and examine tyre after it's inflated to check for a radial bulge.

There's still a chance that something else caused the problem - including faulty tyre or rim.

~PB
 
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