casette shifting, again

On Sat, 15 Dec 2018 19:30:51 +0100, Emanuel Berg
wrote:

AMuzi wrote:

For braking, pad size is a minor factor.
It's all swept area, CF and leverage.
You're right that linkage is efficient but
the leverage is minimal and rubber on chromed
steel has a low CF, made worse by dried
hard pads.

OK, so now it got complicated...

Swept area, should that be big or small for the
brake to be efficient? Small, right? As in disc
brakes where say a single degree of braking on
the small disc translates to a much larger
distance on the big wheel?

Or are disc brakes more efficient because of
material interaction and other technology
improvements alone?

And if the linkage on rod brakes is efficient,
how can leverage be minimal unless there is
something wrong with the levers, and they seem
pretty straightforward to me? Or is it the
shackle that is pulled onto the rim, as opposed
to squeezed into/around it, which is
more efficient?

Also, CF, is that some material
interaction property?

CF might indicate Carbon Fiber but I believe in this case it probably
means Coefficient of Friction :-)

cheers,

John B.