Page 36 - Driving Commercial Vehicles Manual
P. 36
chapter 2 — heavy vehicle braking
The truck is going to take
much longer to stop than
the car — even more so if
going downhill.
Another factor in stopping distances is the slope or grade of the road. A
vehicle travelling down a hill will need a longer stopping distance than a
vehicle travelling at the same speed on a level surface because of the effect
of gravity. A vehicle travelling up a hill will stop in a shorter distance than a
vehicle travelling the same speed on a level surface, again because of the
effect of the grade.
How much heat can brakes handle?
In normal stopping, the brake components heat up to about 120° C (almost
definition 250° F). The brake components are constructed to withstand more heat, and
can handle up to about 250° C under hard braking.
Brake fade occurs when your
brakes stop working properly Heat will continue to build up with excessive hard braking until it exceeds
because they’re overheated. the capability of the brake components to absorb and dissipate the heat. As
Your vehicle takes longer brake drums heat up, they expand away from the brake linings. Too much
to stop, or may not stop at heat can result in brake fade, brake damage and/or brake failure. Brake
all if you haven’t properly components or tires may actually catch fire.
controlled the speed.
Brake drums
Most brake components
operate best at around 120° C
and should not exceed
250° C.
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