Fleet Maintenance - 30

Benefits of retreading

There are two main benefits to using retreads
instead of strictly specifying brand new tires.
One, as noted above, is economical. The other
is environmental.
Economical considerations
Retreads are a more cost-effective solution for
fleets than using new tires because the out-thedoor cost of a retread is much less than a new
tire. Since the fleet is only purchasing new tread,
the physical material and associated labor costs
are both less than they would be for a new tire.
"The utilization of new tires versus retreads
depends on the unique needs of individual fleets
and owner-operators," says Nick Davis, senior
product marketing manager for Goodyear. "The
decision often boils down to cost. The acquisition
price for a retread can be as much as 60 percent
less than a new tire, while providing like-new
tread wear and traction performance."
This lower price tag helps recoup the cost of the
initial tire purchase when it was new. According
to Ron Elliot, marketing, communications, and
inside sales manager for Marangoni Tread North
America, about 70 percent of the cost of a new
tire is in the tire casing. The casing is the layer
of tire beneath the tread - basically, the shell
of the tire, or the foundation that the tread sits
on. Being able to use a casing more than once

Should retreads be
used as steer tires?
Additional safety concerns
to consider.
Retreads are proven to be safe and can be used in all positions on commercial trucks. However, since the maneuverability of the vehicle relies on the steer tires, there remains
safety concerns about using retreads in this position.
Title 49, Part 393.75 (d) of the Federal Motor Carrier Safety
Regulations states that no bus shall be operated with
regrooved, recapped, or retreaded tires on the front wheels.
"Trucking fleets that do not carry passengers are able
to, at their discretion, utilize all-position retreads in
any wheel position including steer tires," says Ron
Elliot, marketing, communications, and inside sales
manager for Marangoni Tread North America.
Tom Clauer, senior manager of commercial and OTR product
planning for Yokohama Tire, confirms that retreads can be
used as steer tires, but only if they are specifically certified.
"In very rare cases, steer positions can be retreaded,"
Clauer says. "This requires the casing to be Certified
Steer. Certified Steer retreads are on casings that
have no repairs or injuries and pass the highest standards of the retreader. This is most common in waste
operations, where slow speeds are the norm."
While retreads can be used as steer tires in these
instances, it is highly recommended that fleets consult an expert before doing so. New tires in the
steer position often remain the safest solution.

30 Fleet Maintenance | June 2019

» A precured retread strip will be spliced
at the seam once applied to the casing.
Photo courtesy of Bandag

increases the mileage a fleet can get from that
tire, decreasing the tire's cost per mile.
Environmental considerations
In addition to cost savings, retreads are also beneficial from an environmental standpoint. Reusing
tires instead of discarding them helps limits used
tires from ending up in landfills. Retreading helps
to defer millions of tires from landfills each year,
according to TRIB.
Retreads also help reduce oil usage, since
it takes approximately seven gallons of oil to
produce a retread versus 22 gallons to produce a
new tire. This helps save North America more than
400 million gallons of oil each year, according to
the U.S. Environmental Protection Agency.

The retread process

Manufacturers typically follow a basic set of steps
outlined by TRIB to produce a safe and reliable
retread tire.
Each step must be completed properly for the
retread tire to have sufficient integrity, say Phil
Boarts and Glenn Stockstill, product category
managers, retread, Michelin. Michelin Retread
Technologies (MRT) and Oliver Rubber retreaders
use proprietary processes to repair and retread
tire casings to ensure this safety.
Michelin and other retread companies customize their retread process to meet their own
standards, but the basics of the process remain
virtually the same.
Ü Initial inspection. Retreading is only possible
if the casing is in good condition, so this step is
critical. Experts inspect the casing for obvious
signs of significant damage that would indicate
the tire is unsafe to retread, or that it would not
survive another duty cycle.
Ü Non-destructive testing. If the casing passes
initial inspection, it goes on to another round
of more in-depth testing to find any potential
internal damage not visible to the human eye.
This usually involves shearography, ultrasound,
or X-ray. "Shearography generates detailed

» The precure
method
of retread
application
uses a preformed and
cured tread,
either in a
strip or full
circle, and
attaches it
to the casing
using a layer
of uncured
rubber.
Photo courtesy
of Bandag

images of the total casing to
identify any underlying damage, and can even
measure casing abnormalities or separations
smaller than the diameter of a human hair,"
says LaTres Jarrett, director of marketing for
Bandag, U.S. and Canada, Bridgestone Americas
Tire Operations.
Ü Buffing. "Once through these initial inspections, a casing is buffed to remove the original tread," Jarrett continues. In this step, the
casing is mounted on a lathe-type machine
and inflated. Then, a computer-controlled rasp
shaves off the old, used tread while the casing
spins. This process is completed to exact specifications to ensure the casing is the right shape
to support the new tread.
Ü Casing preparation and repair. Next, an expert
determines whether any imperfections that
remain after buffing can be repaired or not. If
it is determined that damage is too extensive or
outside acceptable parameters, the casing will
be rejected. Otherwise, the expert will repair
any imperfections to make sure the casing will
last the life of the new tread.
Ü Tread application. Once the casing has been
inspected, buffed, and repaired, it is ready to
receive its new tread. There are two methods
for attaching new tread to the casing: mold cure
and precure.
» Mold cure. In this process, uncured tread
rubber is added to the casing until it is the
correct diameter for the new tread specifica-

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