Maintenance
9-32
Wheel Replacement
When replacing the metal wheels for any
reason, make sure the new wheels are
equivalent to the original factory units in
diameter, rim width and offset.
Tire Traction
Tire traction can be reduced if you drive
on worn tires, tires that are improperly
inflated or on slippery road surfaces.
Tires should be replaced when the tread
depth is at least 2/32 inch (1.6 mm). To
reduce the possibility of losing control,
slow down whenever there is rain, snow
or ice on the road.
Tire Maintenance
In addition to proper inflation, correct
wheel alignment helps to decrease tire
wear. If you find a tire is worn unevenly,
have your dealer check the wheel
alignment.
When you have new tires installed,
make sure they are balanced. This will
increase vehicle ride comfort and tire
life. Additionally, a tire should always
be rebalanced if it is removed from the
wheel.
Tire Sidewall Labeling
This information identifies and describes
the fundamental characteristics of
the tire and also provides the tire
identification number (TIN) for safety
standard certification. The TIN can be
used to identify the tire in case of a
recall.
OLMB073028
1. Manufacturer or brand name
Manufacturer or brand name is shown.
2. Tire size designation
A tire’s sidewall is marked with a tire
size designation. You will need this
information when selecting replacement
tires for your car. The following explains
what the letters and numbers in the tire
size designation mean.
Example tire size designation:
(These numbers are provided as an
example only; your tire size designator
could vary depending on your vehicle.)
205/55R16 91H
205 - Tire width in millimeters.
55 - Aspect ratio. The tire’s section height as a percentage of its width.
R - Tire construction code (Radial).
16 - Rim diameter in inches.
91 - Load Index, a numerical code associated with the maximum load
the tire can carry.
H - Speed Rating Symbol. See the speed rating chart in this section for
additional information.
09
9-35
Temperature A, B & C
The temperature grades are A (the
highest), B and C representing the tire’s
resistance to the generation of heat
and its ability to dissipate heat when
tested under controlled conditions on a
specified indoor laboratory test wheel.
Sustained high temperature can cause
the material of the tire to degenerate
and reduce tire life, and excessive
temperature can lead to sudden tire
failure. Grade C responds to a level
of performance which all passenger
car tires must meet under the Federal
Motor Vehicle Safety Standard No. 109.
Grades B and A represent higher levels
of performance on the laboratory test
wheel than the minimum required by
law.
WARNING
The temperature grade for this tire is
established for a tire that is properly
inflated and not overloaded. Excessive
speed, under-inflation, over-inflation,
or excessive loading, either separately
or in combination, can cause heat build-
up and possible sudden tire failure.
This may cause loss of vehicle control
resulting in an accident.
Tire Terminology and Definitions
Air Pressure
The amount of air inside the tire pressing
outward on the tire. Air pressure is
expressed in pounds per square inch
(psi) or kilopascal (kPa).
Accessory Weight
This means the combined weight of
optional accessories. Some examples
of optional accessories are automatic
transmission, power seats, and air
conditioning.
Aspect Ratio
The relationship of a tire’s height to its
width.
Belt
A rubber coated layer of cords that is
located between the plies and the tread.
Cords may be made from steel or other
reinforcing materials.
Bead
The tire bead contains steel wires
wrapped by steel cords that hold the tire
onto the rim.
Bias Ply Tire
A pneumatic tire in which the plies are
laid at alternate angles less than 90
degrees to the centerline of the tread.
Cold Tire Pressure
The amount of air pressure in a tire,
measured in pounds per square inch (psi)
or kilopascals (kPa) before a tire has built
up heat from driving.
