Text 5114, 33 rader
Skriven 2005-01-15 00:35:08 av Dan Ceppa (1:123/666.0)
Ärende: Stopping Power
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How Brakes Work 
What's behind your car's binders? 
By: Jeff Karr/autoMedia.com 



Brakes themselves have dramatically improved over the years, too.  A few
decades ago, drum brakes were in wide usage, and they're still used on the
rear wheels of many vehicles.  This type of brake employs a drum-shaped
assembly that spins with the wheel.  Inside the drum, stationary "shoes" faced
with replaceable friction material are forced against the drum when you push
the brake pedal.  Drum brakes work well, but they have a hard time shedding
heat well enough to prevent fade when used really hard.  Brake fade occurs
when the brake overheats dramatically; braking power is vastly reduced, and
the brake components and linings can be damaged.

A significant advancement came in the form of disc brakes, which today are
used almost universally on front wheels (which do most of the work under
braking) and on many rear wheels.  Disc brake systems have a metal (or exotic
material in some racing applications) disc (or rotor) that spins along with
the wheel, and a stationary "caliper" that squeezes the disc with replaceable
friction material when the brakes are applied.  With plenty of airflow on the
exposed discs, these types of brakes are much less fade-prone.

Additionally, the discs are often internally vented to allow even greater
airflow.  Back when brake fade was a common problem on long mountainous
descents, drivers would shift the transmission into a lower gear to allow
engine braking to take some of the load off of the brakes.  With modern
brakes, this is usually no longer required, except in situations such as
towing a heavy load downhill.  
--- OMX/Blue Wave/DOS v2.30
 * Origin: Soundly on the Fault Line (1:123/666.0)