Re: Brake Piece

[Paul Fox <pgf@xxxxxxxxxxxxxxxxxxxx>]

zac -- thanks for the reply...
 > 
 > There are some basic laws of physics that apply here.  First if there was a
 > size mismatch between the master and slave cylinders the brakes would never
 > work properly whether or not the pads were worn.  You see one of the great
 > benefits of the disc brake caliper system is that they are self adjusting.
 > What this means is simply that as the pads wear, the calipers retain a bit
 > more fluid so the volume of fluid under pressure required to apply the
 > brakes never changes.  Therefore the concept of the brakes being less
 > effective when the pads have worn is an incorrect one.

yes, after sending my question i realized that that would normally be
the case.  the problem would come if the total volume of the slave
cylinder with worn pads were greater-than, or maybe even
nearly-equal-to, the volume of the master.  in that case, pulling the
lever the whole way in would _not_ yield adequate pressure on the
pads, right?  the lever would bottom out before the system had
pressurized.  i'm not saying this is the Sprint problem, i'm just
pointing it out as a possible design flaw.  this could result from
a late change in the specification for the pads, for instance -- if
they had lower wear limits than the system was designed for, the slave
cylinder would need to be bigger.

 > If you look closely at the reservoir/master cylinder relationship, the
 ...
 > ... Any restriction will cause reduced
 > or inconsistant performance.  Therefore raising the reservoir increases the
 > fluid pressure at the inlet of the master cylinder ensuring that only fluid
 > will be delivered to the caliper.

this makes sense.  the kinked hose in the stock setup certainly _looks_
like a bad thing.  i'm sure the designers thought that having the
top of the reservoir high enough would be good enough, but if people
find that raising it helps, then it must not be (good enough).

paul
=---------------------
  paul fox, pgf@xxxxxxxxxxxxxxxxxxxx (arlington, ma, where it's 25.5 degrees)
  'oh-oh Sprint RS, '91 VX800, DoD #1462, AMA #545601

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