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Maintenance
WARNING - Tire age
Tires degrade over time, even
when they are not being used.
Regardless of the remaining
tread, it is recommended that
tires generally be replaced after
six (6) years of normal service.
Heat caused by hot climates or
frequent high loading condi-
tions can accelerate the aging
process. Failure to follow this
warning can result in sudden
tire failure, which could lead to
a loss of control and an acci-
dent involving serious injury or
death.
4. Tire ply composition and mate-
rial
The number of layers or plies of rub-
ber-coated fabric in the tire. Tire manu-
facturers also must indicate the materi-
als in the tire, which include steel,
nylon, polyester, and others. The letter
"R" means radial ply construction; the
letter "D" means diagonal or bias ply
construction; and the letter "B" means
belted-bias ply construction.
7
50
5. Maximum permissible inflation
pressure
This number is the greatest amount
of air pressure that should be put in
the tire. Do not exceed the maximum
permissible inflation pressure. Refer
to the Tire and Loading Information
label for recommended inflation
pressure.
6. Maximum load rating
This number indicates the maximum
load in kilograms and pounds that
can be carried by the tire. When
replacing the tires on the vehicle,
always use a tire that has the same
load rating as the factory installed
tire.
7. Uniform tire quality grading
Quality grades can be found where
applicable on the tire sidewall
between tread shoulder and maxi-
mum section width.
For example:
TREAD wear 200
TRACTION AA
TEMPERATURE A
Tread wear
The tread wear grade is a compara-
tive rating based on the wear rate of
the tire when tested under controlled
conditions on a specified govern-
ment test course. For example, a tire
graded 150 would wear one-and-a-
half times (1½) as well on the gov-
ernment course as a tire graded 100.
The relative performance of tires
depends upon the actual conditions
of their use, however, and may
depart significantly from the norm
due to variations in driving habits,
service practices and differences in
road characteristics and climate.
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