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Maintenance
4. Tyre ply composition and mate-
rial
The number of layers or plies of rub-
ber-coated fabric are in the tyre. Tyre
manufacturers also must indicate the
materials in the tyre, which include
steel, nylon, polyester, and others.
The letter "R" means radial ply con-
struction; the letter "D" means diago-
nal or bias ply construction; and the
letter "B" means belted-bias ply con-
struction.
5. Maximum permissible inflation
pressure
This number is the greatest amount
of air pressure that should be put in
the tyre. Do not exceed the maximum
permissible inflation pressure. Refer
to the Tyre and Loading Information
label for recommended inflation
pressure.
7
80
6. Maximum load rating
This number indicates the maximum
load in kilograms and pounds that
can be carried by the tyre. When
replacing the tyres on the vehicle,
always use a tyre that has the same
load rating as the factory installed
tyre.
7. Uniform tyre quality grading
Quality grades can be found where
applicable on the tyre sidewall
between tread shoulder and maxi-
mum chapter width.
For example:
TREADWEAR 200
TRACTION AA
TEMPERATURE A
Tread wear
The tread wear grade is a compara-
tive rating based on the wear rate of
the tyre when tested under controlled
conditions on a specified govern-
ment test course. For example, a tyre
graded 150 would wear one-and-a-
half times (1½) as well on the gov-
ernment course as a tyre graded
100.
The relative performance of tyres
depends upon the actual conditions
of their use, however, and may
depart significantly from the norm
because of variations in driving
habits, service practices and differ-
ences in road characteristics and cli-
mate.
These grades are molded on the
side-walls of passenger vehicle
tyres.
The tyres available as standard or
optional equipment on your vehicles
may vary with respect to grade.
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