On 12/6/2019 11:04 AM, Dan S. MacAbre wrote:
AMuzi wrote:
On 12/6/2019 9:56 AM, Dan S. MacAbre wrote:
AMuzi wrote:
On 12/6/2019 4:40 AM, Dan S. MacAbre wrote:
My missus had a caliper brake fall of her bike yesterday.
No harm done, luckily. But between the caliper and the
frame was a rather handy washer that (mostly) stops it
migrating to either side. Sadly, it was lost. It's a
fairly thick washer with about thirty points sticking
out of
each face around the circumference, so that it bites into
both surfaces when tightened. It isn't like those star
washers that sit under a nut to stop it undoing - this is
meant to stop parts turning in either direction once
they're
tightened onto it. I would like to get a replacement, but
I've never seen them anywhere else, and have no idea what
they are called.

'Brake star washer', free to cheap at any LBS (new
calipers ship with extras). BTW it will work without a
star washer just oil the faces of a plain washer. Oh, and
always use a nylok nut when it's not an allen mount
caliper.


Okay, thanks. I'd have thought that oil would allow them to
move, or is that the idea? It will definitely be going back
on with a nyloc nut :-)

A caliper brake centerbolt has to be tight enough to not
fall off (previous installer failed on that point) but has
to remain free to move enough to center over the rim.

http://www.yellowjersey.org/photosfr...t/WEINTECH.JPG


Interesting. So, in a sense, they are allowed to 'float' a
little bit? But not too much. The 'pointy' washer is not
there to hold it solidly in place, but to restrain it a bit.

Right.
The arms float on the spring which passes through a slot in
the centerbolt. People new to bicycles just pull the arms to
one side but on first brake application they move right
back. A slight turn of the centerbolt, either with a wrench
on the centering slots or (as shown above) using the spring
for leverage with a light tap centers the spring slot.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971