>>If disc brakes are so good then why do all tractor/trailer rigs have drum
brakes? This was asked on a "How does it work? segment of "Trucks". The
answer was that drum brakes provide more surface area to stop the big
trucks.
================
Granted they CAN have more surface area than on a car because there are 18
wheels to put them on and the big rig isn't designed for high performance
work. ie, playing in curvy roads.
>>I'd say with todays technology they could make a drum setup for
todays passenger vehicle that stops every bit as good as disc brakes.
=================
Possibly, but the penalty in weight addition would be prohibitive.
>>Since the market is pushing how great disc brakes are the auto
manufactures are
not really interested. Plus as mentioned disc brakes are easier to maintain
and probably easier and cheaper to manufacture. So take a look at a big rig
next time. If drum brakes faded so much and did not have such great
stopping power I'd stay away from the front of those big trucks. They have
drums all the way around.
=================
The big rig brakes are pneumatic not hydraulic. The reason they don't fade
is that the brakes are pressurize to release no pressurize to apply. This
is one of many reasons that truck drivers don't shut down the rig when
stopping for a short time, it can take longer for the pressure to build back
up than it took the driver to answer nature's call. Also big rigs in panic
stops and during long descents can and often do have their brake pads get so
hot they catch fire.
03 CC Dak 2wd
Stays away from big rigs because he recalls 2 equations
from engineering:
P=MV aka inertia
KE=MV^2 aka kinetic energy
when the M=40 tons..................
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