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From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: tire-boots
Date: 22 Feb 1999 19:10:29 GMT

Bob G writes:

> What are tire-boots?

These were common in the days of automobile tires before the advent of
tubeless tires and safety rims from which a tire cannot be removed
manually.  They are structural tire casing inserts, usually similar to
tire casing, that are placed over ruptures or larger cuts in the
casing through which the tube would burst if the blemish were not
covered.

For bicycles a piece of lightweight tire casing, preferably with no
rubber tread on it, about 5-6 cm long, and half round with respect to
the tire on which it is used, makes a good general purpose boot.
These are best made from a tubular tire that has at best a thin tread.

What often escapes attention is that if the boot is not feathered to a
paper thin edge, the tube will chafe through at the edge of the boot
and cause a slow leak.  On tubular tires, boot MUST be feathered and
be glued into the casing with latex.  This assumes the tube is latex
or some other light weight cross section, because if not, there is no
reason to use a tubular.

The old story of using a dollar bill is based on the high quality
paper used for US currency.  It is not a good boot.  The reason that
paper is poor for this use is that it is not laterally deformable
without tearing.  Laying a standard business card in the tire between
tread and tube demonstrates this well, because after a few miles the
card will be confetti because the bias ply of the rolling tire casing
distorts in a way that paper cannot.  This distortion is also the
reason for fresh patches on a tube to leak.

Jobst Brandt      <jbrandt@hpl.hp.com>


From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Emergency Tire Fix:
Date: 7 Aug 1997 16:40:41 GMT

Mark Schinman writes:

> I blew a tire the other day.  There was a 1 centimeter vertical or
> radial cut in the side wall.  I decided against putting a new tube
> in as it didn't seem like it would work.  Is there a good way to
> make a temporary patch to get you home?  Duck Tape?

Yes, duct tape makes a good boot because it contains strong fibers and
is moldable to the shape, but you must put it on the inside of the
tire casing, preferably wrapping two layers from edge to edge, over
the bead to give it good anchorage.  The amount of squirming that goes
on in a tire becomes apparent if you put a piece of paper between the
tube and tire and see the confetti it turns into in a few miles.

In the old days of cloth handlebar tape, this was a source of boots
and bandage material.  Electrical tape won't hold as a boot because it
deforms plastically.

Jobst Brandt      <jbrandt@hpl.hp.com>



 
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