<[email hidden]> wrote in message
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Quoted message said:A friend just gleefully asked me how many strands of wire there are in
a bicycle cable, what the twist rate is, and why.
Honesty being the best policy, I replied that I don't know and that
it's probably none of his damned business, but that I'd ask.
He pointed out that he can answer the question for ethernet cables.
I know that cable housing varies between brakes and gearshifts, but I
have no idea about the cables that go inside them.
Does anyone know how many little wire strands make up a typical cable
and how many twists are normal per inch or foot? Do all cables use a
standard number of strands and twist rate? If so, do more strands
twisted more tightly make a better cable? Rated strength? Do cable
manufacturers disagree?
Cables are commonly made in any number of configurations; cycle cables are a
small subset of these.
The most basic construction of a cable uses seven starnds of the same
diameter; conveniently for those of us who operate in Euclidean geometry six
such starnds will completely surround the seventh. The twist is either
right-hand or left-hand; from the reading I did several decades ago
right-hand twist was more common - but which way was "right" and which
"left" I cannot remember, and it probably does not matter.
Surround a seven strand core requires a total of nineteen (7 + 12). Cable
constructiion can be quite complex as the size and requirements go up - some
cables can be (were?) made with hemp cores, which were soaked in oil for
lubrication and corrosion resistance, and there are various combinations of
left and right twists of left- and right-twisted starnds. Thicker strands
are more wear resistant, but are less flexible, and the twist arrangements
also have particular characteristics.
For your question, why don't you take an old cable - or snip a bit off the
end - and count?
