In Gear - Today's Trucking

Magic Gas?
tech tips Nitrogen tire fills are nothing new, but new technology
makes it affordable for truck fleets of all sizes. By Jim Park
There’s nothing magical about
nitrogen’s ability to prolong tire
life. It won’t restore the original
luster to the innards of your tires, it doesn’t
smell better, and neither will it save the
environment. But using nitrogen rather
than compressed air to inflate tires has
two principle advantages. First, its permeation
rate is 35 percent slower than air,
resulting in tires that stay properly inflated
longer, keeping tires running cooler,
improving tread life, minimizing sidewall
flex, and overall, lowering the rate of pressure-induced
blowouts. Second, nitrogen
is dry and contains no moisture. Nitrogen
is inert so rust cannot form since there is
neither oxygen nor moisture present to
cause oxidation of the wheel.
Remove the oxygen and the moisture
PSSST: Nitrogen’s better
than air in your tires.
from inside your tires and replace it with a
gas that stays in place longer, runs cooler,
and won’t corrode the inner surfaces of
the wheel rim or the tire and you’ve solved
many of your tire management issues—all
at once.
Until recently, there has not been a convenient,
reliable, economic means of distributing
nitrogen to inflate tires. In the
past, nitrogen would be provided in large
liquid tankers transferring the nitrogen to
large on-site storage vessels, or it was
delivered in high-pressure cylinders. But
recently, technologies
have been developed
for on-site use that
purifies regular compressed
air into high
purity nitrogen.
In Gear
There are two types of nitrogen generating
systems: membrane generators and
pressure swing adsorber generators
(PSA). Both produce 98-to-99-percent
pure nitrogen, but the PSA generators are
typically rated for less than 90 psi output—a
little weak for heavy-duty truck
applications, but suitable for light- and
medium-duty trucks. The output of
membrane generators, however, is equal
to the input pressure.
The nitrogen generators are rated for
certain volumes. Higher volume units are
capable of filling over 30 truck tires per
hour from 150-psi compressed air systems.
There are no storage reservoirs required,
as the nitrogen is used as it’s produced.
The definitive study on nitrogen-filled
truck tires, “Million Mile Truck Tires—
Available Today” was conducted in 1986
by Lawrence Sperberg
and clearly demonstrates
the advantages
of using nitrogen for
truck tire inflation.
Sperberg found in a
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