7-50
Maintenance
4. Tire ply composition andmaterial
There are a number of layers or plies
of rubber-coated fabrics in the tire.
Tire manufacturers indicate the
materials on the tire, such as steel,
nylon and polyester. 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.
5. Maximum permissible infla-tion pressure
This number indicates the air pres-
sure limit of the tire. Do not inflate the
tire over the maximum pressure.
Refer to "Tire and Loading
Information Label" for the recom-
mended inflation pressure.
6. Maximum load rating
This number indicates the maximum
loading capacity in kilograms or in
pounds that a tire can carry. When
replacing the tires, always use the
tire of the same load rating as the
original one.
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 a tire wear-out
rating, which is recorded while being
tested under a controlled condition
on a test course specified by a gov-
ernment. For example, a tire, of
which the tread wear grade is 150,
would wear out one-and-a half times
(1½) faster than a tire graded 100.
The actual tread wear rating
depends on the actual driving condi-
tions. In addition, the actual tread
wear rating may significantly vary
from the tread wear grade due to a
lot of variations, such as driving
habits, maintenance conditions, road
characteristics and climates.
These grades are written on the tire
side wall of a passenger vehicle. The
available tires with the standard or
optional equipment may vary with
respect to this grade.
Traction - AA, A, B & C
The traction grades, from the highest
to the lowest, are AA, A, B and C.
Those grades represent the stopping
performance level of a tire measured
on a wet test surface specified by the
government under a controlled con-
dition. A tire marked with the letter, C,
may have poor traction.
The traction grade of a tire is
based on a braking traction test,
while driving straight ahead. The
test does not include accelerat-
ing, cornering, hydroplaning, or
towing situations.
WARNING
