jbeattie writes:

On Tuesday, April 9, 2019 at 11:01:18 AM UTC-7, Frank Krygowski wrote:
On Tuesday, April 9, 2019 at 10:05:07 AM UTC-4, jbeattie wrote:

The hydraulic pads self-adjust, which is a nice feature -- and
there were times when I forgot to dial-in the pad on my cable
front brake and had some scary moments on the sled-runs on my
commute route. That was my own fault.

Since I've done only short rides, not any great distances on a disc brake bike
(cable or hydraulic): How often do you have to "dial-in" your cable disc
brakes?

For me, after I ran out of lever travel and didn't stop. I let it get
sloppy, and it went from bad to worse during a rainy ride down some
very steep hills.

I usually adjusted every month or less to keep the brakes firm. I
don't know what is recommended, and that undoubtedly varies based on
individual use, weather and pad type. You hear stories about DH
riders blowing through pads in a day or two, although those are
hydraulic pads that self adjust. I knew my BB7 pads were shot when I
got that pinging sound of the return spring hitting the rotor. Ooops.

That, BTW, is another issue with hydraulics. You have to police
hydraulic pads because they will keep adjusting until you're braking
with the aluminum carriers. When you adjust the pads manually on cable
discs, at least you have a reminder to look at the pads -- whether you
decide to look is up to you. Hydraulic pads are supposed to be
replaced at .5mm, and I just measure them in place with a feeler gauge
but you can take them out and do it with a micrometer. That is now an
additional maintenance requirement and part of the care and feeding of
discs.

Car disk brake pads generally have a little metal tab that extends
towards the disk to the wear limit of the pad. Its purpose is just to
squeal painfully *before* the pad is actually worn through. I'm not
sure of any reason this couldn't work for bicycles.