Tube failure

<!doctype html public “-//w3c//dtd html 4.0 transitional//en”>
<html> Hi all,
<p>My son, Ben, has a 20" Jugglebug with the blue nylon wheel. For
the second time now, the uni’s tube has suddenly blown as the unicycle
sat alone in a corner and we’re wondering what’s going on. I
don’t remember exactly where the tube blew the first time but it seems
to be in the same general location as the most recent failure. It
may be just coincidence. What I do remember is that I was sitting
right next to the uni watching TV when the tube blew and it scared the
life out of me! When the tube failed, it blew about a 6" slit
down the length which is probably typical. I’ve examined the
inner rim and tire and have found nothing notable. What’s more
confusing is that in the first failure, we were running about 50 lbs.
in the 40 psi 20x1.75 tire. In the second, Ben had about 20 psi
in the tire (and new tube) in order to practice hopping. When
installing tubes, I always pump them up a bit, let out the air to let
the tube adjust, then pump it up a second time to pressure. We
did not talc the inside of the tire last time but do so for our tires
now. We have not had a tube failure on any of our other uni’s.
<q>Any ideas, similar experiences, advice?
<r>Thanks, <br>Bruce <br><A
HREF=“http://move.to/daup”>http://move.to/daup</A></html

In article <3B277009.57C11F8E@inwave.com>, Bruce Edwards
<REMOVE.TO.REPLYyoopers@inwave.com> wrote: )<!doctype html public
“-//w3c//dtd html 4.0 transitional//en”> )<html> )Hi all, )<p>My son, Ben,
has a 20" Jugglebug with the blue nylon wheel. For )the second time
now, the uni’s tube has suddenly blown as the unicycle )sat alone in a
corner and we’re wondering what’s going on. I don’t )remember
exactly where the tube blew the first time but it seems to be )in the same
general location as the most recent failure. It may be )just
coincidence.

Probably not coincidence. Catastrophic failures like this usually indicate
that the tube got pinched somewhere. The two most common causes are a slit
in the tire sidewall (this happened on the cheap Cheng Shin tire that came
with my first uni), or the rim tape covering the spoke holes coming loose
or wearing through so the tube can poke into the hole. A couple of other
possibilities: you might have pinched the tube when you installed it; you
should take care to make sure the tube isn’t twisted, and that it’s not
caught between the rim and the tire anywhere. Sometimes that error doesn’t
show up until you pump up to high pressure. And it’s also possible that
the tire lost its grip on the rim and pulled off enough to let the tube
poke through; this might be a possibility with a plastic rim. -Tom

I thought I configured my browser (Netscape) to send plain text email but
I see by Tom’s response that I am still putting out HTML formatting. I’ve
thrown another switch in my browser now. Please let me know if I’m still
shipping out HTML formatting.

Thanks, Bruce http://move.to/daup

Tom Holub wrote:
>
> In article <3B277009.57C11F8E@inwave.com>, Bruce Edwards
> <REMOVE.TO.REPLYyoopers@inwave.com> wrote: )<!doctype html public
> “-//w3c//dtd html 4.0 transitional//en”> )<html> )Hi all, )<p>My son,
> Ben, has a 20" Jugglebug with the blue nylon wheel. For )the
> second time now, the uni’s tube has suddenly blown as the unicycle )sat
> alone in a corner and we’re wondering what’s going on. I don’t
> )remember exactly where the tube blew the first time but it seems to be
> )in the same general location as the most recent failure. It may
> be )just coincidence.
>
> Probably not coincidence. Catastrophic failures like this usually
> indicate that the tube got pinched somewhere. The two most common causes
> are a slit in the tire sidewall (this happened on the cheap Cheng Shin
> tire that came with my first uni), or the rim tape covering the spoke
> holes coming loose or wearing through so the tube can poke into the
> hole. A couple of other possibilities: you might have pinched the tube
> when you installed it; you should take care to make sure the tube isn’t
> twisted, and that it’s not caught between the rim and the tire anywhere.
> Sometimes that error doesn’t show up until you pump up to high pressure.
> And it’s also possible that the tire lost its grip on the rim and pulled
> off enough to let the tube poke through; this might be a possibility
> with a plastic rim. -Tom

Bruce,

Your e-mailer sends out HTML code that my Outlook 2000 doesn’t process. It
comes out like this:

> <!doctype html public “-//w3c//dtd html 4.0 transitional//en”>
> <html> Hi all,
> <p>My son, Ben, has a 20" Jugglebug with the blue nylon wheel. For

You might want to see if your emailer has a setting for plain text (which
I prefer) or something other than that HTML version.

On to the tire. Here are possible causes of a tire blowing on its own:

  • too much pressure
  • defect in tube or tire
  • tire improperly seated
  • sharp object on rim or inside tire

Since this tire blew twice, the last item on the list is the most likely.
When repairing a puncture, you’re always supposed to check inside the tire
for sharp protrusions, and you can also check the rim for same. I usually
forget to do this. But if the cause is something sharp stuck inside the
tire, it will just keep popping them.

Run your fingertips slowly and gently around inside the tire (or wear a
glove and do it fast), feeling for anything not smooth.

If you don’t find anything, move on to the next possibility. If it’s your
son’s unicycle, you probably don’t have too much pressure. On a properly
seated tire, you can usually get away with 100 lbs or more before anything
bad happens (not true with a Coker!).

Defects are rare, but the cheaper the tube and tire, the more possibility
they could play a part.

I had a blowout once that ruined a tire. It was on my old track uni, which
I used to run at high pressure (about 90-100). Luckily the blowout
happened in the first 1/2 mile of a five mile each way ride to Jones Beach
(no phones or gas stations on the way). Bam! The tire was probably seated
wrong. But after this blowout the tire was no longer straight. It had a
zigzag in it that made it useless. This was an older tire, and probably a
cheap one too.

An improperly seated tire could be the second most likely culprit. Check
your tire after mounting it to make sure it fits evenly all the way
around. Many tires have a line on them near the rim, so you can rotate the
tire and see if this line is moving in and out. When first putting a tire
on, I usually put a little air into the tube, then gently bounce the wheel
on the ground while slowly rotating it. Check for this alignment before
putting the rest of the air in.

That concludes this tire-changing workshop.

Good luck, John Foss, the Uni-Cyclone jfoss@unicycling.com
www.unicycling.com

“Someone who thinks logically is a nice contrast to the real world.”

From: Don Tai <don_tai@yahoo.co.uk> Subject: Re: Tube failure To:
yoopers@inwave.com

Bruce, I’m having difficulties posting to the newsgroup, so please post
this reply to your question, for the benefit of the newsgroup. I hope
this helps.

Don Tai

Bruce, I have a uni with a plastic wheel as well, and I’ve blown 3 inner
tubes, scaring the stuffing out of me each time. The daughter (5 yrs old)
was also suitably unimpressed. The plastic wheel is unlike a typical
spoked wheel in many respects. Because there are no thin, metal spokes
there’s no need for an inner tube liner, because the inside of the rim
will be completely smooth, compliments of modern day plastic technology.
So there’s no need to worry about narrow and sharp objects puncturing your
inner tube. Besides, if you did get something sharp piercing your tube it
wouldn’t have put in a 6" gash down the length of the tube, but a small
puncture mark. In my case I found the culprit to be the rim, specifically
because my plastic rim does not have a bead ridge, which will lock the
tire’s bead (metal wire on both sides of the tire) into the rim. The bead
ridge is easy to find on a typical spoked rim. On the inside of the rim
edge, where the tire’s bead meets the rim, you’ll see a metal bump on the
inside of the rim. This holds the tire’s bead into the rim. On my plastic
rim there is no bead ridge and the plastic in this area of the rim is
completely smooth. This does not allow the tire’s bead to securely lock
into the rim. This is a design flaw of the plastic rim. When you put air
into the tire the inner tube expands, and puts pressure on the tire. When
this air pressure increases it may overcome the friction between the tire
and the rim, which is not locked in tightly anyway, because the rim has no
bead ridge. The tire comes away from the rim, thus allowing the inner tube
to escape from the confines of the rim and tire. But the inner tube walls
are quite thin and cannot take this air pressure without being confined
and therefore breaks it’s walls, thereby explaining your 6" gash. There
are some dubious solutions you could consider.

  1. get another spoked uni; this was my ultimate solution

  2. try a tighter fitting tire

  3. decrease your tire pressure

  4. avoid putting any additional pressure on the tire, which includes
    hopping, drops, and other self-induced sudden decreases in elevation

  5. periodically decrease tire pressure and examine the tire bead to ensure
    it is seated properly.

            I hope this helps. The uni is still good for
         typical riding, so you can still have lots of fun.
    

Don http://torontounicyclists.tripod.com Don_TaiATyahooDOTcoDOTuk but I
live in Toronto

In addition to what John Foss mentioned, another possibility is a bad rim
strip. Most unicycle wheels have a rubber rim strip inside to protect the
tube from the spoke holes. I have not found the rubber rim strips to be
too reliable. They have a tendency to move and expose the spoke holes and
then you get a flat. I prefer to use rim tape. Rim tape is a thick fabric
tape. Since it is tape it stays in place and will not suddenly become an
exhibitionist and start exposing nipples. Velox is one brand of rim tape.
You can find it at any bike store.

john_childs

>From: Bruce Edwards <REMOVE.TO.REPLYyoopers@inwave.com>
>
>Hi all, My son, Ben, has a 20" Jugglebug with the blue nylon wheel.
>For the second time now, the uni’s tube has suddenly blown as the
>unicycle sat alone in a corner and we’re wondering what’s going on. I
>don’t remember exactly where the tube blew the first time but it seems to
>be in the same general location as the most recent failure. It may be
>just coincidence. What I do remember is that I was sitting right next to
>the uni watching TV when the tube blew and it scared the life out of me!
>When the tube failed, it blew about a 6" slit down the length which is
>probably typical. I’ve examined the inner rim and tire and have found
>nothing notable. What’s more confusing is that in the first failure, we
>were running about 50 lbs. in the 40 psi 20x1.75 tire. In the second, Ben
>had about 20 psi in the tire (and new tube) in order to practice hopping.
>When installing tubes, I always pump them up a bit, let out the air to
>let the tube adjust, then pump it up a second time to pressure. We did
>not talc the inside of the tire last time but do so for our tires
>now. We have not had a tube failure on any of our other uni’s. Any
>ideas, similar experiences, advice? Thanks, Bruce


Get your FREE download of MSN Explorer at http://explorer.msn.com

Don,

After my inspections, it’s not a puncture problem and makes the most sense
that it’s a matter of the tire letting loose from the rim bead. We have
another plastic-wheeled Jugglebug that has not experienced the problem
although I don’t think it’s tire pressure has been as high and it has not
received the same treatment, i.e., hopping. It’s troubling though that the
tire would let loose suddenly while not being used and sitting alone in
the corner. It’s got to be a bad spot in the bead on either the rim or the
tire. I’ll take a closer look. Thanks for your input.

Bruce http://move.to/daup

> From: Don Tai <don_tai@yahoo.co.uk> Subject: Re: Tube failure To:
> yoopers@inwave.com
>
> Bruce, I’m having difficulties posting to the newsgroup, so please post
> this reply to your question, for the benefit of the newsgroup. I hope
> this helps.
>
> Don Tai
>
> Bruce, I have a uni with a plastic wheel as well, and I’ve blown 3 inner
> tubes, scaring the stuffing out of me each time. The daughter (5 yrs
> old) was also suitably unimpressed. The plastic wheel is unlike a
> typical spoked wheel in many respects. Because there are no thin, metal
> spokes there’s no need for an inner tube liner, because the inside of
> the rim will be completely smooth, compliments of modern day plastic
> technology. So there’s no need to worry about narrow and sharp objects
> puncturing your inner tube. Besides, if you did get something sharp
> piercing your tube it wouldn’t have put in a 6" gash down the length of
> the tube, but a small puncture mark. In my case I found the culprit to
> be the rim, specifically because my plastic rim does not have a bead
> ridge, which will lock the tire’s bead (metal wire on both sides of the
> tire) into the rim. The bead ridge is easy to find on a typical spoked
> rim. On the inside of the rim edge, where the tire’s bead meets the rim,
> you’ll see a metal bump on the inside of the rim. This holds the tire’s
> bead into the rim. On my plastic rim there is no bead ridge and the
> plastic in this area of the rim is completely smooth. This does not
> allow the tire’s bead to securely lock into the rim. This is a design
> flaw of the plastic rim. When you put air into the tire the inner tube
> expands, and puts pressure on the tire. When this air pressure increases
> it may overcome the friction between the tire and the rim, which is not
> locked in tightly anyway, because the rim has no bead ridge. The tire
> comes away from the rim, thus allowing the inner tube to escape from the
> confines of the rim and tire. But the inner tube walls are quite thin
> and cannot take this air pressure without being confined and therefore
> breaks it’s walls, thereby explaining your 6" gash. There are some
> dubious solutions you could consider.
> 1. get another spoked uni; this was my ultimate solution
> 2. try a tighter fitting tire
> 3. decrease your tire pressure
> 4. avoid putting any additional pressure on the tire, which includes
> hopping, drops, and other self-induced sudden decreases in elevation
> 5. periodically decrease tire pressure and examine the tire bead to
> ensure it is seated properly.
>
> I hope this helps. The uni is still good for
> typical riding, so you can still have lots of fun.
>
> Don http://torontounicyclists.tripod.com Don_TaiATyahooDOTcoDOTuk but I
> live in Toronto

Bruce, All three of my “blowouts” occurred while the uni was sitting in
the corner doing nothing. Check to see if you really HAVE a rim bead. On
my plastic uni I do not.

Don

Bruce Edwards wrote:

> Don,
>
> After my inspections, it’s not a puncture problem and makes the most
> sense that it’s a matter of the tire letting loose from the rim bead.
> We have another plastic-wheeled Jugglebug that has not experienced
> the problem although I don’t think it’s tire pressure has been as
> high and it has not received the same treatment, i.e., hopping. It’s
> troubling though that the tire would let loose suddenly while not
> being used and sitting alone in the corner. It’s got to be a bad spot
> in the bead on either the rim or the tire. I’ll take a closer look.
> Thanks for your input.
>
> Bruce http://move.to/daup
>
> > From: Don Tai <don_tai@yahoo.co.uk> Subject: Re: Tube failure To:
> > yoopers@inwave.com
> >
> > Bruce, I’m having difficulties posting to the newsgroup, so please
> > post this reply to your question, for the benefit of the newsgroup. I
> > hope this helps.
> >
> > Don Tai
> >
> > Bruce, I have a uni with a plastic wheel as well, and I’ve blown 3
> > inner tubes, scaring the stuffing out of me each time. The daughter (5
> > yrs old) was also suitably unimpressed. The plastic wheel is unlike a
> > typical spoked wheel in many respects. Because there are no thin,
> > metal spokes there’s no need for an inner tube liner, because the
> > inside of the rim will be completely smooth, compliments of modern day
> > plastic technology. So there’s no need to worry about narrow and sharp
> > objects puncturing your inner tube. Besides, if you did get something
> > sharp piercing your tube it wouldn’t have put in a 6" gash down the
> > length of the tube, but a small puncture mark. In my case I found the
> > culprit to be the rim, specifically because my plastic rim does not
> > have a bead ridge, which will lock the tire’s bead (metal wire on both
> > sides of the tire) into the rim. The bead ridge is easy to find on a
> > typical spoked rim. On the inside of the rim edge, where the tire’s
> > bead meets the rim, you’ll see a metal bump on the inside of the rim.
> > This holds the tire’s bead into the rim. On my plastic rim there is no
> > bead ridge and the plastic in this area of the rim is completely
> > smooth. This does not allow the tire’s bead to securely lock into the
> > rim. This is a design flaw of the plastic rim. When you put air into
> > the tire the inner tube expands, and puts pressure on the tire. When
> > this air pressure increases it may overcome the friction between the
> > tire and the rim, which is not locked in tightly anyway, because the
> > rim has no bead ridge. The tire comes away from the rim, thus allowing
> > the inner tube to escape from the confines of the rim and tire. But
> > the inner tube walls are quite thin and cannot take this air pressure
> > without being confined and therefore breaks it’s walls, thereby
> > explaining your 6" gash. There are some dubious solutions you could
> > consider.
> > 1. get another spoked uni; this was my ultimate solution
> > 2. try a tighter fitting tire
> > 3. decrease your tire pressure
> > 4. avoid putting any additional pressure on the tire, which includes
> > hopping, drops, and other self-induced sudden decreases in
> > elevation
> > 5. periodically decrease tire pressure and examine the tire bead to
> > ensure it is seated properly.
> >
> > I hope this helps. The uni is still good for
> > typical riding, so you can still have lots of fun.
> >
> > Don http://torontounicyclists.tripod.com Don_TaiATyahooDOTcoDOTuk but
> > I live in Toronto

Bruce,

This flick of a switch made you send plain text, in case no one told you
yet. Glad you did it, makes it so much more readible.

Klaas Bil

On Wed, 13 Jun 2001 10:28:01 -0500, Bruce Edwards
<REMOVE.TO.REPLYyoopers@inwave.com> wrote:

>I thought I configured my browser (Netscape) to send plain text email but
>I see by Tom’s response that I am still putting out HTML formatting. I’ve
>thrown another switch in my browser now. Please let me know if I’m still
>shipping out HTML formatting.
>
>Thanks, Bruce http://move.to/daup
>
>Tom Holub wrote:
>>
>> In article <3B277009.57C11F8E@inwave.com>, Bruce Edwards
>> <REMOVE.TO.REPLYyoopers@inwave.com> wrote: )<!doctype html public
>> “-//w3c//dtd html 4.0 transitional//en”> )<html> )Hi all, )<p>My son,
>> Ben, has a 20" Jugglebug with the blue nylon wheel. For )the
>> second time now, the uni’s tube has suddenly blown as the unicycle )sat
>> alone in a corner and we’re wondering what’s going on. I don’t
>> )remember exactly where the tube blew the first time but it seems to be
>> )in the same general location as the most recent failure. It may
>> be )just coincidence.
>>
>> Probably not coincidence. Catastrophic failures like this usually
>> indicate that the tube got pinched somewhere. The two most common
>> causes are a slit in the tire sidewall (this happened on the cheap
>> Cheng Shin tire that came with my first uni), or the rim tape covering
>> the spoke holes coming loose or wearing through so the tube can poke
>> into the hole. A couple of other possibilities: you might have pinched
>> the tube when you installed it; you should take care to make sure the
>> tube isn’t twisted, and that it’s not caught between the rim and the
>> tire anywhere. Sometimes that error doesn’t show up until you pump up
>> to high pressure. And it’s also possible that the tire lost its grip on
>> the rim and pulled off enough to let the tube poke through; this might
>> be a possibility with a plastic rim. -Tom


“To trigger/fool/saturate/overload Echelon, the following has been picked
automagically from a database:” “Mossad, CIA, Iran”

Glad to know. Thanks.

Bruce http://move.to/daup

Klaas Bil wrote:
>
> Bruce,
>
> This flick of a switch made you send plain text, in case no one told you
> yet. Glad you did it, makes it so much more readible.
>
> Klaas Bil
>
> On Wed, 13 Jun 2001 10:28:01 -0500, Bruce Edwards
> <REMOVE.TO.REPLYyoopers@inwave.com> wrote:
>
> >I thought I configured my browser (Netscape) to send plain text email
> >but I see by Tom’s response that I am still putting out HTML
> >formatting. I’ve thrown another switch in my browser now. Please let me
> >know if I’m still shipping out HTML formatting.
> >
> >Thanks, Bruce http://move.to/daup
> >
> >Tom Holub wrote:
> >>
> >> In article <3B277009.57C11F8E@inwave.com>, Bruce Edwards
> >> <REMOVE.TO.REPLYyoopers@inwave.com> wrote: )<!doctype html
> >> public “-//w3c//dtd html 4.0 transitional//en”> )<html> )Hi all,
> >> )<p>My son, Ben, has a 20" Jugglebug with the blue nylon wheel.
> >> For )the second time now, the uni’s tube has suddenly blown as the
> >> unicycle )sat alone in a corner and we’re wondering what’s going
> >> on. I don’t )remember exactly where the tube blew the first
> >> time but it seems to be )in the same general location as the most
> >> recent failure. It may be )just coincidence.
> >>
> >> Probably not coincidence. Catastrophic failures like this usually
> >> indicate that the tube got pinched somewhere. The two most common
> >> causes are a slit in the tire sidewall (this happened on the cheap
> >> Cheng Shin tire that came with my first uni), or the rim tape
> >> covering the spoke holes coming loose or wearing through so the tube
> >> can poke into the hole. A couple of other possibilities: you might
> >> have pinched the tube when you installed it; you should take care to
> >> make sure the tube isn’t twisted, and that it’s not caught between
> >> the rim and the tire anywhere. Sometimes that error doesn’t show up
> >> until you pump up to high pressure. And it’s also possible that the
> >> tire lost its grip on the rim and pulled off enough to let the tube
> >> poke through; this might be a possibility with a plastic rim. -Tom
>
> –
> "To trigger/fool/saturate/overload Echelon, the following has been
> picked automagically from a database:" “Mossad, CIA, Iran”