In Gear - Today's Trucking

some vehicles are designed for a 20-percent
improvement in stopping distances
while others are designed for a 30-percent
or 25-percent reduction. “All the comments
on the proposed rule will be in by
April. Then we’ll see NHTSA determine a
minimum stopping distance, one that is
practical for the majority of commercial
vehicles on the road, and let the market
determine the solution.”
5If most trucks can satisfy new requirements
using bigger drum brakes,
where does that leave the disc-brake market
in North America?
The proposed performance standards
will require brake engineers to maximize
the potential of S-cam brakes, but the
round after that most assuredly will
require a disc-brake solution. NHTSA’s
tests showed that only all-disc-brake
configurations can reliably achieve a
30-percent reduction in stopping distance
over the existing
355-foot mark, a benchmark
of 249 feet.
“You should educate
yourself about disc brakes
now, on your own terms,
before the regulations
require you to do so,” advises
Johnston. “There’s a lot
to learn about how discs
work, how to maintain
them, and how they perform
on the road.”
Clark agrees. “I think the
disc brake is going to be
something everyone understands
better and becomes
more available in manufacturers’
data books,” he says.
“The torque output of a
disc is so consistent. We’ve
taken drivers who used to
disconnect the steers, when
that was legal, and we put
them in vehicles with discs
on the steers and they love them.”
As an intermediate step, Clark suggests,
spec disc brakes on the steer axle of your
next tractor. “Even if it’s one truck, the
experience will give you a head start on
managing the transition to discs at some
point down the road,” Clark says. “And that
point will come.”
For some truck owners, discs will be a
In Gear
necessity in 2008 or 2009 when the rules
are expected to take effect, either in combination
with high-performance drums or
at every wheel position on the vehicle.
Disc-braking performance comes with a
price: currently about $1,000 US to equip a
three-axle tractor, according to estimates
in NHTSA’s proposed rulemaking.
In the meantime, there are steps you
can take now to improve the braking
performance on your equipment.
Instead of waiting two years for a rule
that will only apply to the next new truck
you buy, look at how you can get more
reliable stopping performance out of the
trucks you have today, says BrakePro’s
Tom Golden.
“Put your trucks on a performancebased
brake tester, determine the ability of
your brakes to stop your vehicle, and develop
a maintenance program to address the
problems,” he says. Use high-quality com-
WIDER IS BETTER: The more lining a drum can
grab, the greater the stopping power.
ponents from suppliers who can support
those products here in North America. Air
disc brake components, Golden adds,
require an even higher degree of inherent
quality than do drum brakes.
“The reality is,” he says, “bigger shoes,
better friction materials—none of it
amounts to anything if your brakes aren’t
in good working order.” ▲
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