Fat Rider and Tubes Blowing Weekly

[davek]

Pete Biggs wrote:
> Not necessarily if there were no particularly sharp or recessed bits and
> the tube was tough and the pressure wasn't high. However, I do find it
> incredible that anyone would supply Elisa with wheels/bike with no rim
> tape.

Back in the day when I was completely clueless about bike maintenance
(these days I am only partially clueless), I once removed the rim tape
from my rear wheel while changing a tube because I thought it looked a
bit tatty. Somehow it didn't occur to me that it was there for a
purpose and should have been replaced.

Amazingly, I had no p+nct+re in that tyre for ages - when I did
eventually get a p+nct+re, it was while on a club ride. You can imagine
the amusement of my clubmates upon noticing the absence of rim tape...

d.

 

[davek]

David L. Johnson wrote:
> I do second the recommendation
> for Velox rim tape. Being French, it should be easy to find.

And it has "fond de jante" written along it, so you'll have no trouble
recognising it (no chance of mistaking it for, eg, bar tape!)

d.

 

[davek]

sothach wrote:
> Monsuier: Oh, 'bande de jante'...
> Me: er, yeah.

I can understand why the bike shop owner would be confused at someone
going in and asking him for "the bottom of the rim"...

("fond de jante" describes where it goes, "bande de jante" describes
what it is)

d.

 

[Dave Larrington]

In article <[email protected]>, Mike K Smith (mks-
[email protected]) wrote:

> There isn't a lot of choice of 520 tyres, so if there are any other
> Airnimal riders out there I would like to hear of their experiences
> either with the Kendas or with other tyres.

I have no connection with Airnimal other than having been married to the
person who drew the head-tube badge, but there are assorted Panaracer
tyres available in 520, and most people seem to rate them pretty highly.

Though the P+nct+r+ Fairy /did/ attack the (559) Pasela on the rear of
my Speedmachine this morning chiz.

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
Bandersnatch? I would never have guessed.

 

[James Thomson]

"davek" <[email protected]> wrote:

> sothach wrote:

> > Monsuier: Oh, 'bande de jante'...
> > Me: er, yeah.

> I can understand why the bike shop owner would be confused at
> someone going in and asking him for "the bottom of the rim"...

I can't: "fond de jante" is perfectly common usage. Perhaps it was the
definite article that threw him.

> ("fond de jante" describes where it goes, "bande de jante"
> describes what it is)

Where it goes describes what it is. Metonymy in action.

James Thomson

 

[davek]

James Thomson wrote:
> I can't: "fond de jante" is perfectly common usage.

Sure - I was being slightly facetious for minor comic effect. Very
minor.

> Where it goes describes what it is. Metonymy in action.

I had to look that up. Fortunately, I knew exactly where to look - this
wonderful website: <url:http://humanities.byu.edu/rhetoric/silva.htm>

d.

 

[Mike K Smith]

Dave Larrington wrote:

> I have no connection with Airnimal other than having been married to the
> person who drew the head-tube badge, but there are assorted Panaracer
> tyres available in 520, and most people seem to rate them pretty highly.

I've used Paselas in 700x25C and found them OK, but the Technovas have
had some negative sentiment.

A thread at bikeforums
(http://www.bikeforums.net/archive/index.php/t-81795) claims "Don't even
think about the Panaracer Technovas though, as they are the worst tyres
I have ever fitted on a bike!"

Similar sentiments here -
http://myweb.tiscali.co.uk/13q11/cycling/airnimal.html

I'm tempted to pay the extra and get the Schwalbe Stelvio folding tyres
which have recently been released in 520.

BTW if you ever see TWFKAML tell her I think the Airnimal badge is
excellent.

 

[James Thomson]

"Elisa Francesca Roselli" <[email protected]> wrote:

> The inner tubes on Flyzipper keep blowing. I've had one blow-out
> on the rear wheel and two on the front wheel in the space of less
> than a month!

An update:

I rode out to Elisa's yesterday evening, and we had a look at the front
wheel of Flyzipper. The rims are open in section, similar to but deeper
than the example here:

http://www.art-collection.com.tw/case/alexrims/product_detail.asp?btn=7&cat=6&id=110

There was a thin plastic rim tape fitted, and no sign of protruding spokes
or damage to the tape, but the tubes had obviously been failing in the
spoke bed. We decided to improvise a thicker rim tape with a roll of Velox
that I'd brought along, some vinyl insulating tape, and a butchered inner
tube. Time will tell if that does the trick. Fingers crossed: pride is at
stake.

I was too tired (having barely slept the previous night) to tackle the rear
wheel yesterday, so that's for another day.

Refreshed after a good night's sleep, it seems to me that the mechanics of
the problem are as follows. All of the examples of tubes that we had to
hand - the Cheng Shins that Elisa had been using, and the Schwalbes I
brought along, were quite long, so that when only slightly inflated they
sat in the outer diameter of the tyre. As the pressure is increased, the
tube will expand to fill the tyre first, then the part of the tube spanning
the rim-well will expand into the well, stretching significantly as it does
so. This leaves a variation in tension around the circumference of the
tube, with the part adjacent to the spoke bed being under the greatest
stress. I'm guessing that tube ruptures are a result of the tube attempting
(asymmetrically) to equalize tension, being unable to move laterally in the
spoke bed due to the protruding nipples, and so tearing. The thicker tape
we improvised should help both by cushioning the tube against the nipples,
but also by filling space in the deep rim-well, reducing the peak tension
in the tube.

Also had a quick look at Behemoth's rear tyre. It seems the last repairer
had caught the tube under the tyre bead. The bead had lifted, allowing the
tube to balloon out and rupture, then partly fallen back, trapping the
ruptured tube and sealing the leak.

James Thomson

 

[STEVE]

James Thomson wrote:
> "Elisa Francesca Roselli" <[email protected]> wrote:
>
>> The inner tubes on Flyzipper keep blowing. I've had one blow-out
>> on the rear wheel and two on the front wheel in the space of less
>> than a month!
>
> An update:
>
> I rode out to Elisa's yesterday evening, and we had a look at the front
> wheel of Flyzipper. The rims are open in section, similar to but deeper
> than the example here:
>
> http://www.art-collection.com.tw/case/alexrims/product_detail.asp?btn=7&cat=6&id=110
>
> There was a thin plastic rim tape fitted, and no sign of protruding spokes
> or damage to the tape, but the tubes had obviously been failing in the
> spoke bed. We decided to improvise a thicker rim tape with a roll of Velox
> that I'd brought along, some vinyl insulating tape, and a butchered inner
> tube. Time will tell if that does the trick. Fingers crossed: pride is at
> stake.
>
> I was too tired (having barely slept the previous night) to tackle the rear
> wheel yesterday, so that's for another day.
>
> Refreshed after a good night's sleep, it seems to me that the mechanics of
> the problem are as follows. All of the examples of tubes that we had to
> hand - the Cheng Shins that Elisa had been using, and the Schwalbes I
> brought along, were quite long, so that when only slightly inflated they
> sat in the outer diameter of the tyre. As the pressure is increased, the
> tube will expand to fill the tyre first, then the part of the tube spanning
> the rim-well will expand into the well, stretching significantly as it does
> so. This leaves a variation in tension around the circumference of the
> tube, with the part adjacent to the spoke bed being under the greatest
> stress. I'm guessing that tube ruptures are a result of the tube attempting
> (asymmetrically) to equalize tension, being unable to move laterally in the
> spoke bed due to the protruding nipples, and so tearing. The thicker tape
> we improvised should help both by cushioning the tube against the nipples,
> but also by filling space in the deep rim-well, reducing the peak tension
> in the tube.
>
> Also had a quick look at Behemoth's rear tyre. It seems the last repairer
> had caught the tube under the tyre bead. The bead had lifted, allowing the
> tube to balloon out and rupture, then partly fallen back, trapping the
> ruptured tube and sealing the leak.
>
> James Thomson
>
>

 

[STEVE]

James Thomson wrote:
snip
>


This leaves a variation in tension around the circumference of the
tube, with the part adjacent to the spoke bed being under the greatest
stress.


Sounds like a good argument in favor of tire talc.

 

[STEVE]

James Thomson wrote:

This leaves a variation in tension around the circumference of the
> tube, with the part adjacent to the spoke bed being under the greatest
> stress. I'm guessing that tube ruptures are a result of the tube attempting
> (asymmetrically) to equalize tension, being unable to move laterally in the
> spoke bed due to the protruding nipples, and so tearing. The thicker tape
> we improvised should help both by cushioning the tube against the nipples,
> but also by filling space in the deep rim-well, reducing the peak tension
> in the tube.


Tire talc might help

 

[James Thomson]

"STEVE" <[email protected]> wrote:

> Tire talc might help

Good suggestion, but Elisa routinely talcs her tubes.

James Thomson

 

[Elisa Francesca Roselli]

As he writes, James Thompson did indeed come round yesterday evening,
most generously unsparing of his time, energy and expertise.

Although he has now arrived at a plausible hypothesis for the blow-outs,
he agrees with me that there was no obvious anomaly, either in the rims,
or the tyres, or the tubes, or in how I was fitting them, or in the bike.

The blow-outs having all been on the rim side of the tubes, the only
course of action was to reinforce protection on that side. James had
brought some rim tape - _ruban_ de fond de jante if you want to be
pedantic about the French - and we created a further layer of protection
by cutting a slender strip out of one of the defunct tubes. The original
yellow tape went on over that, holding it all in place.

I did not ride today because I was working locally and because of high
winds, but am pleased to report that, as of my check in the garage this
evening, the tyre was still hard. I pray that it remains so over the
weekend in the hope of resuming my commute on Monday. If it doesn't,
we're frankly in the Twilight Zone.

James also very kindly brought me two new inner tubes of the correct
specifications. To my joy, he has identified a local shop which actually
keeps them in stock! No more month-long wrangles on Ebay in Babel Fish
German. These tubes will not have wintered in my garage with the others,
so if there is some kind of environmental factor affecting them, freeze
or canicule or gas fumes or whatever, these new tubes should be free of
that.

Also I used my less-preferred bike pump to inflate the tyres. The other
pump is more efficient and easier by far to use, but I seem to have much
worse luck with it. Perhaps that pump is jinxed.

So I'll keep everyone posted as to the state of the tyre - thanks to all
the gentle bike maniacs who find this topic interesting enough to bear
with me so patiently. And a thousand thanks to James.

EFR
Ile de France

 

[Elisa Francesca Roselli]

James Thomson wrote:
> "STEVE" <[email protected]> wrote:
>
>
>>Tire talc might help
>
>
> Good suggestion, but Elisa routinely talcs her tubes.

Perhaps they're allergic to the rose perfume?

EFR
Ile de France

 

[David Martin]

Elisa Francesca Roselli wrote:
> James Thomson wrote:
> > "STEVE" <[email protected]> wrote:
> >
> >
> >>Tire talc might help
> >
> >
> > Good suggestion, but Elisa routinely talcs her tubes.
>
> Perhaps they're allergic to the rose perfume?

I don't know if that was spoken in jest but you might be right. There
are preservatives to keep the perfume smelling as it should so
unperfumed talc or french chalk should be used, not perfumed.

A pot should last for ages, or get some normal school chalk (ecrit?)
and a bit of sandpaper.

...d

 

[STEVE]

Elisa Francesca Roselli wrote:
>
> Perhaps they're allergic to the rose perfume?


So what was the final discovery as to why all those tubes blew out????
Preservatives in the talc is hard to believe!


Inquiring minds want to know!

 

[Peter Headland]

May we conclude that you remain blow-out free since James' visit?

--
Peter Headland

 

[[email protected]]

Elisa Francesca Roselli writes:

> The inner tubes on Flyzipper keep blowing. I've had one blow-out on
> the rear wheel and two on the front wheel in the space of less than
> a month! The tyres are inflated to about 5 bar - it says minimum
> 4.5 and maximum 6.5. I've checked and checked on the inside of the
> tyres and rims and can find nothing sharp or outstanding that could
> cause this. The tubes always blow AT A STANDSTILL, generally when I
> have just finished riding or when the bike is parked, so it's not
> the typical visit from the puncture fairy.

> It's getting scary as the size of inner tube used on this Dahon is
> not available in France except by special order. I fortunately have
> a few with me and have ordered more, but at this rate I'm going to
> have trouble keeping up the supply of tubes. Moreover, although I
> managed the change on the front wheel myself yesterday, I don't know
> how to mess with the back wheel midst all its gears, and having it
> changed cost me 70 Euros last time around (35 just in taxi to get to
> the LBS).

> So I'm thinking, is this about rider weight? The limit on a Dahon
> is 105 kg. Fully dressed, with bags, water and some groceries, I'm
> well over that. Moreover the trips I'm taking include some nasty
> offroad sections with mud, gravel and pointy stones that I cannot
> always avoid. I would of course rather the tubes blew than the
> frame break!

I'm unclear on what you are calling a "blowout". With respect to
tires, that term describes a loud explosion of the inner tube,
something that occurs only when the it comes out of the tire. If that
is the case, it is because the tire was improperly mounted, such that
the tube is caught under the bead, preventing proper seating of the
tire on the rim.

http://www.sheldonbrown.com/brandt/blowouts.html

Jobst Brandt