Page 29 - ATR 5 2013

BRAKING WELL,
Continued from page 21

marily aimed at improving directional
stability and control using anti-lock
brakes, they also reinstated stopping
distance mandates that had been
invalidated in 1978 by the U.S Court of iN published commeNts prior to his
Appeals for the 9th Circuit because of
reliability issues. appearaNce, burkhart said accideNts are a
Those rules included the stopping $52 billioN-a-year issue for the iNdustry
distances that are now being further aNd the costs were risiNg.
reduced. NHTSA data showed the old
stopping distances had slightly reduced
fatal and injury-producing crashes, but
the number of registered heavy vehicles
had increased, which kept the total
crash counts high.
“There are a number of simple
and effective manufacturing solutions involves expanded use of higher output involved air disc brakes, because com-
that vehicle manufacturers can use air disc brakes for the heavy tractor paratively few are being manufactured
to meet the requirements of this final requirements. For foundation drum compared to the drum brakes. Phase
rule,” reads NHTSA documentation. brakes, highlights include a structurally II does include a solution calling for
“These solutions include installation of reinforced S Shoe, expanded use of the expanded output of air disc brakes.
enhanced drum brakes, air disc brakes, high performance ES drum brake and “Today air disc is a bit pricey. Even
or hybrid disc/drum systems. We note higher performance friction materials. then, it’s not terrible,” he said.
that currently a number of vehicles in Phase II also includes significant Air disc brakes are probably the
the commercial fleet already utilize vehicle testing for brake compatibility wave of the future, Collins said. They
these improved braking systems and and wear balance. are used widespread in Europe and
already realize performance that would Collins said it is important for manufacturing is underway in this
meet the requirements of the amended truck manufacturers to use the right country.
standard.” friction compound and pointed out “We have fleets buying it,” Collins
Companies like Bendix and Haldex there is no requirement for any certain said. “Everybody assumes air disc brakes
have been producing advanced braking brand, though he said some companies are the next thing coming and they
components that make the stopping are trying to scare potential customers would be right to assume that.”
mandates a reality. into using their product. Also looking to the future, Collins
High performance drum brake sys- “There’s no way I could tell some- said, it is possible FMCSA will become
tems feature larger chambers, bronze one you had to,” he said. involved and eventually turn out some
camshaft bushings, precision cams, The friction material used should regulations.
single anchor pins for maximum wear- be based on how the vehicle in question “There’s been talk in the industry,
able lining and an increased braking is going to be used — long haul versus because most manufacturers used a
surface that improves heat dissipation in the city, for example, Collins said. very specific component of brake shoe,
and reduces fade, thus leading to a lon- “You pick the one that’s right for FMCSA will eventually add something
ger brake life. you,” he said. “There are right materi- to their guide that will affect brake shoe
“They just made the brakes bigger,” als based on applications. Don’t buy on manufacturing,” Collins said.
Collins said. price.” But because of the way NHTSA
In tests the new systems show a The problems with the bigger brakes went about its business, new regula-
significant reduction to “in stop fade” have been few and mostly noise related, tions won’t have the surprise, negative
which happens when the friction mate- chatter and vibration, Collins said, impact, some other government man-
rial reaches its temperature limit, as though there was a recall related to a dates have had.
well as higher average torque. non-compatible component. “Everybody in the industry is look-
Highlights of RSD Phase II include “Very minor,” he said of the com- ing forward now,” Collins said.
thorough testing for wear and balance plications and expense.
and an air disc brake solution that The priciest issues so far have

arKansas trucKing report | issue 5 2013 29