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Old November 21st 09, 12:05 PM posted to rec.bicycles.tech
thirty-six
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Posts: 10,049
Default Tire-making, continued....

On 21 Nov, 08:56, DougC wrote:
thirty-six wrote:

kevlar 'wires' are used with hook bead rim otherwise known as crochet
bead rim. *If you are not using thistype of rim you need to use steel
wire for the tyre edge as its not the strength of the wire which
matteers so much as its ability to constrain, in other words, its
elasticity. A llarger section or higher running pressure tyre will
need stiffer wires to prevet tyre lift off and non-requisit
demounting. *in other words you'll likely roll a tyre with kevlar
bead. *


Kevlar has only about 1% elongation before breaking.


Never mind running into problems about constraining the tyre to rim,
you are making it difficult for youself in construction. With steel
wires you have some stability during assembly upon which to wrap your
'cloth'. BTW if you dont use a weftless warp cloth, or nearly so, you
will likely be dissapointed with the results,. You may get your
required look but the performance will be poor.


One thing I noticed about the tire bead and cables--the physical tire
bead (the one that you can see) is much larger than the actual cables
that really hold the tire from expanding.... so I wonder if the external
rubber ridge is needed at all?


Not if the wiring is stiff enough. The tyre you have has most likely
been constructed in a way to facilitate cheapest cost. This does not
make it a bad example, but the differences between tyres should show
you what you can vary.

It might help protect the real bead from
idiots with tire levers but I don't use tire levers, so that don't apply
to me. ,,,,,,,


You said the tyre was coiled up in a box, this requires thin wires,
the beading compensates for the thin wires on a genuine clincher rim.
The cost savings are in storage and transportation space along with
the ability to market the tyres from a non bike specific shop.

I have a set of Big Apples I can't use because they won't
sit properly on the target bike's rims--the tire seats with a low spot
and I've never found any technique to help it. If the rubber ridge is
the cause of the seating problem and it's not necessary anyway, the
outside of it could be -carefully- trimmed off somewhat without harming
the tire.


Try the tyre in a different orientation to establish is the low spot
due to the tyre or the rim. Use plenty of french chalk// talcum.

You possibly can buy good tyre casing 'material' but you may
have to buy it by the mile. *Other than laying out your own threads
and spraying them with latex to produce a single ply faric I cant see
you getting a small quatity of tyre casing material. *a loom is not
necessary just wrap a card with your thin thread, spray with latex and
cut the fabric at 45deg.


I'll just have to use what I can find, at this point I doubt I'd find
anything quite like the "real thing" and making it myself doesn't sound
very practical.



Well the alternative I see are to either beg at the door of a tyre
factory / look in their waste or salvage from used tyres including
motorcycle and sports car tyres, you'll be lookin at the side wall for
v=clues.. So if you know of any domestic tyre manufacturers, perhaps
you could approach them for assembled casinggs or offcuts of casing
material.
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