Andy Dingley wrote:
Chris Bacon wrote:
Andy Dingely wrote
Don't use Bowden (or Teleflex) cable for brakes.

Now what. Why?


Bowden (in the strictest sense) cables are designed to accurately
transmit a position down a flexible cable. They're appropriate for
gearcables.

Brake cables are designed to transmit a tensile force. Position is
less important, so a certain amount of ghost movement caused by cable
flex is acceptable. It would be a problem on a gear cable if you
shifted gear every time you moved the bars.

As a result of these requirements, the cable outers are constructed
differently. Position-sensitive cables are multiple longitudinal wires
in a jacket. If you flex this cable, the outer doesn't change length.
Tension cable outers use a single wire spiral. This is more flexible,
and it also changes in length (slightly) if you bend it, causing the
apparent fake movement of the inner cable. Using brake cable for
gears gives poor shifting that's prone to false shifts and moving
gates.

The serious implication for bikes is if you use "gear" cable for
brakes. Wear on the outer jacket can weaken the integrity of the outer
cable such that hard emergency braking can burst it (the wires
separate). The inner cable pulls through the gap and you lose your
brakes. This is also most likely to happen when you _apply_ the
brakes, not in an obvious manner beforehand.

Well, I don't think I've seen so much utter claptrap for absolutely
ages. Sorry, but *really*.