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Intended Outboard Sidewall:The side of an asymmetrical tire,
that must always face outward
when mounted on a vehicle.
Kilopascal (kPa)
:The metric
unit for air pressure.
Light Truck (LT-Metric) Tire
:A tire used on light duty trucks
and some multipurpose
passenger vehicles.
Load Index
:An assigned
number ranging from 1 to 279
that corresponds to the load
carrying capacity of a tire.
Maximum In ation Pressure
:The maximum air pressure to
which a cold tire can be inflated.
The maximum air pressure is
molded onto the sidewall.
Maximum Load Rating
:The load rating for a tire at the
maximum permissible inflation
pressure for that tire.Maximum Loaded Vehicle
Weight
:The sum of curb weight,
accessory weight, vehicle
capacity weight, and production
options weight.
Normal Occupant Weight
:The
number of occupants a vehicle
is designed to seat multiplied
by 150 lbs (68 kg). SeeVehicle
Load Limits on page 8-12.
Occupant Distribution
:Designated seating positions.
Outward Facing Sidewall
:The
side of an asymmetrical tire that
has a particular side that faces
outward when mounted on a
vehicle. The side of the tire that
contains a whitewall, bears white
lettering, or bears manufacturer,
brand, and/or model name
molding that is higher or deeper
than the same moldings on the
other sidewall of the tire.Passenger (P-Metric) Tire
:A tire used on passenger
cars and some light duty trucks
and multipurpose vehicles.
Recommended In ation
Pressure
:Vehicle
manufacturer’s recommended
tire inflation pressure as shown
on the tire placard. SeeTire
Pressure on page 9-54and
Vehicle Load Limits on
page 8-12.
Radial Ply Tire
:A pneumatic
tire in which the ply cords that
extend to the beads are laid at
90 degrees to the centerline of
the tread.
Rim
:A metal support for a tire
and upon which the tire beads
are seated.
Sidewall
:The portion of a tire
between the tread and the bead.
Vehicle Care 9-53
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Speed Rating:An alphanumeric
code assigned to a tire indicating
the maximum speed at which a
tire can operate.
Traction
:The friction between
the tire and the road surface.
The amount of grip provided.
Tread
:The portion of a tire that
comes into contact with the road.
Treadwear Indicators
:Narrow
bands, sometimes called wear
bars, that show across the tread
of a tire when only 1/16 inch
(1.6 mm) of tread remains.
SeeWhen It Is Time for New
Tires on page 9-62.
UTQGS (Uniform Tire Quality
Grading Standards)
:A tire
information system that provides
consumers with ratings for a
tire’s traction, temperature,
and treadwear. Ratings are
determined by tire manufacturers
using government testingprocedures. The ratings are
molded into the sidewall of the
tire. SeeUniform Tire Quality
Grading on page 9-65.
Vehicle Capacity Weight
:The number of designated
seating positions multiplied by
150 lbs (68 kg) plus the rated
cargo load. SeeVehicle Load
Limits on page 8-12.
Vehicle Maximum Load on the
Tire
:Load on an individual tire
due to curb weight, accessory
weight, occupant weight, and
cargo weight.
Vehicle Placard
:A label
permanently attached to a
vehicle showing the vehicle’s
capacity weight and the original
equipment tire size and
recommended inflation pressure.
See “Tire and Loading
Information Label” underVehicle
Load Limits on page 8-12.
Tire Pressure
Tires need the correct amount
of air pressure to operate
effectively.
Notice:Do not let anyone
tell you that under-in ation or
over-in ation is all right. It is
not. If your tires do not have
enough air (under-in ation),
you can get the following:
Too much exing
Too much heat
Tire overloading
Premature or irregular wear
Poor handling
Reduced fuel economy
If your tires have too much air
(over-in ation), you can get
the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road
hazards
9-54 Vehicle Care
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A vehicle specific Tire and
Loading Information label
is attached to your vehicle.
This label shows your vehicle’s
original equipment tires and the
correct inflation pressures for
your tires when they are cold.
The recommended cold tire
inflation pressure, shown on the
label, is the minimum amount of
air pressure needed to support
your vehicle’s maximum load
carrying capacity.
For additional information
regarding how much weight
your vehicle can carry, and an
example of the Tire and Loading
Information label, seeVehicle
Load Limits on page 8-12.
How you load your vehicle
affects vehicle handling and
ride comfort. Never load your
vehicle with more weight than
it was designed to carry.When to Check
Check your tires once a
month or more. Do not forget
to check the compact spare
tire, if the vehicle has one.
The compact spare should be at
60 psi (420 kPa). For additional
information regarding the
compact spare tire, seeCompact
Spare Tire on page 9-83.
How to Check
Use a good quality pocket-type
gage to check tire pressure.
You cannot tell if your tires are
properly inflated simply by
looking at them. Radial tires may
look properly inflated even when
they are under-inflated. Check
the tire’s inflation pressure when
the tires are cold. Cold means
your vehicle has been sitting for
at least three hours or driven no
more than 1 mile (1.6 km).Remove the valve cap from the
tire valve stem. Press the tire
gage firmly onto the valve to
get a pressure measurement.
If the cold tire inflation pressure
matches the recommended
pressure on the Tire and Loading
Information label, no further
adjustment is necessary. If the
inflation pressure is low, add air
until you reach the recommended
amount.
If you overfill the tire, release air
by pushing on the metal stem
in the center of the tire valve.
Re-check the tire pressure with
the tire gage.
Be sure to put the valve caps
back on the valve stems.
They help prevent leaks by
keeping out dirt and moisture.
Vehicle Care 9-55
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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. The
grade C corresponds 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. It should be
noted that the temperature grade
for this tire is established for a tire
that is properly inflated and not
overloaded. Excessive speed,
underinflation, or excessive
loading, either separately or in
combination, can cause heat
buildup and possible tire failure.Wheel Alignment and
Tire Balance
The tires and wheels on the vehicle
were aligned and balanced carefully
at the factory to give the longest tire
life and best overall performance.
Adjustments to wheel alignment and
tire balancing will not be necessary
on a regular basis. However, if there
is unusual tire wear or the vehicle
pulls to one side or the other, the
alignment should be checked. If the
vehicle vibrates when driving on a
smooth road, the tires and wheels
might need to be rebalanced.
See your dealer/retailer for proper
diagnosis.
Wheel Replacement
Replace any wheel that is bent,
cracked, or badly rusted or corroded.
If wheel nuts keep coming loose,
the wheel, wheel bolts, and wheel
nuts should be replaced. If the wheel
leaks air, replace it (except some
aluminum wheels, which can
sometimes be repaired). See your
dealer/retailer if any of these
conditions exist.
Your dealer/retailer will know the
kind of wheel you need.
Each new wheel should have
the same load-carrying capacity,
diameter, width, offset, and be
mounted the same way as the
one it replaces.
Vehicle Care 9-67