Fleet Maintenance - 42

GUEST EDITORIAL
Here's what fleets can do to ensure a
high-quality inflation program.

Use calibrated gauges

It is important to ensure tire gauges in the
shop and on the vehicle are accurate. Gauges
get dropped, and even if they don't look like it,
they're sensitive pieces of equipment. If a fleet
is not testing each gauge and recalibrating them
monthly against a master, there is a good chance
they are inflating tires to the wrong level.
It is a good idea to have a psi test station set
up along with a master gauge in a highly visible area of the shop. Some fleets have drivers
swap out their gauges for a calibrated gauge
once a month. It is difficult to have a good tire
program if the gauges can't be trusted.
»Fleets need to think differently about air pressure; the tire doesn't
actually support the load, the air does.
Photo courtesy of Cooper Tire

Keeping
tire pressure
at optimum
levels
Proper inflation levels are
crucial to maximize tire life.

Tire inflation has long been a topic of
conversation when it comes to commercial
vehicle tires.
Proactive fleets have tire inflation well under
control, and that helps maximize tire life and
keeps tire costs in check. Since quality tires
that are properly maintained affect driver
satisfaction, tire life, and fuel economy, inflation maintenance is an opportunity to reduce
costs and improve driver retention.

By Jason C. Miller

NATIONAL FLEET CHANNEL SALES MANAGER,
COOPER TIRE
Jason C. Miller is Cooper Tire's national fleet channel sales
manager. He has spent years working in all aspects of
the tire industry, mastering complex tire programs for
some of the largest fleets in North America. A member
of the Technology and Maintenance Council (TMC) of the
American Trucking Association, Jason is also a TIA certified
tire instructor and former ASE certified technician. He has
a bachelor's degree in information technology and a master of science degree in integrated marketing communication from Northwestern University. Jason is the author of
the book, "Selling by the Number" and has written numerous tire-related articles for industry publications.

42 Fleet Maintenance | May 2020

Start with the chart

Cooper Tire, like most major tire manufacturers, provides load-inflation tables based upon
Tire and Rim Association guidelines. With a
typical 6x4 legal load, there will be 34,000 lbs
being carried by eight drive tires, or 4,250 lbs
per tire. The table shows the drive tires can
support that load at as little as 75 psi fully loaded. Yet, many fleets run a standard inflation
pressure at 100 psi because, they say, "That's
what we've always done. It's easy for our drivers to remember, and it gives us more margin
for error if a tire leaks."
While overinflation may be inefficient and
costly, significant underinflation can be catastrophic. A blowout could occur. So what's the
optimal pressure? Like so many things in life,
the answer is: it depends.
Every tire and fleet has a "personality." The
most cost-effective tire programs come from
matching the right tire to the right application
at the right inflation pressure. It takes a little
time and some discipline, but the effort will
pay off.
The bottom line is fleets need to think differently about air pressure. The reality is the tire
doesn't actually support the load, the air does.
Inflation pressure primarily manages two
things: the shape of the tire footprint and the
amount of sidewall deflection.
Overinflation can pose several problems. The
biggest is premature and irregular wear since
the tire won't have an optimal footprint patch
to the road. It will ride more on the crown of
the tire so part of the tread is scrubbing its way
into and then out of the contact patch causing
rapid and uneven wear. Traction will also be
compromised, and that really comes into play
in winter. There may also be an increase in
the occurrence of impact breaks since the tire
sidewalls have less flex. Finally, overinflation
impacts fuel economy.
Fleets need to break this cycle and keep tires
at their proper inflation level. Only then can
they see the true performance engineered into
the tire, and that will provide savings in the
form of lower cost of ownership.
The impact of not following the chart is big.
While operations vary significantly, running

tires that are just 10 percent underinflated may
require them to be removed from service 10
percent early. At 20 percent underinflated, tread
life may be reduced by as much as 25 percent.

Audit inflation levels

Yard checks may seem inconvenient but are
necessary. It is important to benchmark tire
inflation and identify problem areas. Only
then can a fleet take steps to improve their
tire program.
For example, what percent of a fleet's duals
- both on the tractor and trailer - have inflation pressures within 5 psi of each other? Just
a 5 psi difference in inflation between duals is
the equivalent of one tire having a circumference that is 5/16" smaller. That means during
every rotation cycle, the smaller circumference
tire must scuff ahead to keep up with the tire
with more inflation. These tires rotate around
500 times per mile so simple math means 500
multiplied by 5/16" translates to 156.3" per
mile, or about 13' per mile. Imagine dragging
a tire 13 feet every mile, under load. The impact
is significant.

Tire-related concerns
beyond air pressure

Another area of tire service to watch is retreads.
Similar to inflation, circumference is key. In
some cases, fleets will get identical retreads
back from their retreader, but the casings may
be different. Each brand and model may have
a slightly different diameter, so while two tires
may look identical when they come back from
the retreader, one may be significantly taller
than the other. This is why it is recommended
that fleets use a circumference band, measuring tape, or have a height gauge mounted in the
shop to check circumference. Otherwise, a fleet
could be putting mismatched duals together
which will cause one tire to wear prematurely.

Incentivize drivers

With today's advanced trucks, it's possible to
gauge how well a driver handles the truck; hard
braking, quick starts, and fuel economy can
all be tracked, making trends evident. Some
fleets offer bonuses for tire wear and proper
tire inflation. If the driver keeps tire inflation at
the proper level and does fingertip diagnostics
on each tire during pre-trip inspections, tires
will have longer lives. How drivers take care
of tires can be easily tracked when the truck
returns to the terminal for maintenance.
If these tips are followed, fleets stand a solid
chance of pulling the drive tires at 2/32nds and
the steers at 4/32nds, and casings should be in
great shape for retreading. A fleet can extend
its budget on tires by maximizing mileage
and retreads. Proper tire selection is one key
to doing that, but it's the maintenance practices
- especially proper tire inflation - that keeps
trucks and trailers operating as efficiently and
safely as possible.

Fleet Maintenance

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