Reinforced tread. A reinforced tread is con-
equipment." The Navy has established rebuilding
criteria consistent with tire technology and service
structed with fabric cord or other reinforcing materials
experience. By using this approach, functionally sound
as an integral part of the tread. See figure 7-11.
tire carcasses are returned to qualified contractors for
Reinforced cut-resistant tread. A reinforced
rebuilding. In conjunction with these procedures, Navy
cut-resistant tread combines the features of both the
laboratories monitor rebuilt tires to ensure the fleet
cut-resistant and reinforced-tread designs.
receives a satisfactory product. The military rebuilt tire
is as safe as, or safer than, a new tire because it is built
Ply Rating
on a service-tested tire carcass, whereas a new tire has
had no service use to establish its construction
Reference to the number of cord fabric plies in a
reliability and performance suitability. Rebuilt tires are
tire has been superseded by the term ply rating. This
subjected to quality control procedures that are far
term is used to identify a tire's maximum recommended
more stringent than those imposed on a new tire. Unlike
load for specific types of service. It does not necessarily
a new tire, each rebuilt tire receives a final
represent the number of cord fabric plies in a tire. Most
nondestructive inspection with laser beam optical
nylon cord tires have ply ratings greater than the actual
holographic methods. This procedure detects
number of fabric plies in the cord body.
separations, voids, and multiple cord fractures within
the carcass, which is cause for tire rejection.
Tire Rebuilding/Retreading
Size Designation
The rebuilding of aircraft tires has been practiced
for many years. A rebuilt tire is one that has a new tread
Figure 7-12 shows the points of measurement used
section attached to a carcass or worn tire. Each rebuilt
to designate the size of a tire. For example, a tire with a
tire saves aircraft operators approximately 75 percent
size designation of 26 X 6.6 would have an outside
of the cost of a new tire. Data shows that a rebuilt tire
diameter (measurement A) of 26 inches and a
gives service comparable to a new tire. The General
cross-sectional width (measurement B) of 6.6 inches.
Accounting Office (GAO) and the Department of
The letter X merely separates the two measurements. If
Defense (DOD) policy mandates "aircraft tires will be
the tire's size designation were 26 X 6.6 -10, then the
rebuilt in all cases where economics can be realized
tire would have a rim diameter (measurement C) of 10
without affecting safety of personnel and/or
Figure 7-11.--Sectional view of two aircraft tires showing different construction details.
7-10
