Black plate (42,1)Chevrolet Impala Owner Manual - 2011
10-42 Vehicle Care
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 psi (pounds per
square inch) or kPa (kilopascal)
before a tire has built up heat
from driving. See Tire Pressure
on page 10‑44. Curb Weight
:The weight of a
motor vehicle with standard and
optional equipment including the
maximum capacity of fuel, oil,
and coolant, but without
passengers and cargo.
DOT Markings
:A code molded
into the sidewall of a tire
signifying that the tire is in
compliance with the U.S.
Department of Transportation
(DOT) motor vehicle safety
standards. The DOT code
includes the Tire Identification
Number (TIN), an alphanumeric
designator which can also
identify the tire manufacturer,
production plant, brand, and
date of production.
GVWR
:Gross Vehicle Weight
Rating. See Vehicle Load Limits
on page 9‑12. GAWR FRT
:Gross Axle Weight
Rating for the front axle.
See Vehicle Load Limits on
page 9‑12 .
GAWR RR
:Gross Axle Weight
Rating for the rear axle.
See Vehicle Load Limits on
page 9‑12.
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.
Black plate (43,1)Chevrolet Impala Owner Manual - 2011
Vehicle Care 10-43
Maximum Inflation 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
68 kg (150 lbs). See Vehicle
Load Limits on page 9‑12.
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 Inflation
Pressure
:Vehicle
manufacturer's recommended
tire inflation pressure as shown
on the tire placard. See Tire
Pressure on page 10‑44
andVehicle Load Limits on
page 9‑12. 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.
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.
Black plate (44,1)Chevrolet Impala Owner Manual - 2011
10-44 Vehicle Care
Treadwear Indicators:Narrow
bands, sometimes called wear
bars, that show across the
tread of a tire when only 1.6 mm
(1/16 inch) of tread remains.
See When It Is Time for New
Tires on page 10‑52.
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 testing procedures.
The ratings are molded into the
sidewall of the tire. See Uniform
Tire Quality Grading on
page 10‑55. Vehicle Capacity Weight
:The
number of designated seating
positions multiplied by
68 kg (150 lbs) plus the rated
cargo load. See Vehicle Load
Limits on page 9‑12.
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 9‑12.
Tire Pressure
Tires need the correct amount of
air pressure to operate
effectively.
Notice: Do not let anyone tell
you that under‐inflation or
over‐inflation is all right. It is
not. If your tires do not have
enough air (under‐inflation),
you can get the following:
.Tire overloading and
over-heating which could
lead to a blowout.
.Premature or
irregular wear.
.Poor handling.
.Reduced fuel economy.
Black plate (45,1)Chevrolet Impala Owner Manual - 2011
Vehicle Care 10-45
If your tires have too much
air (over‐inflation), you can
get the following:
.Unusual wear.
.Poor handling.
.Rough ride.
.Needless damage from
road hazards.
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, see
Vehicle
Load Limits on page 9‑12 . 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 420 kPa
(60 psi). For additional
information regarding the
compact spare tire, see
Compact Spare Tire on
page 10‑68. How to Check
Use a good quality pocket-type
gauge 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 1.6 km (1 mile).
Remove the valve cap from the
tire valve stem. Press the tire
gauge 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.
Black plate (53,1)Chevrolet Impala Owner Manual - 2011
Vehicle Care 10-53
SeeTire Inspection on page 10‑51
and Tire Rotation on page 10‑51 for
additional information.
The rubber in tires ages over time.
This is also true for the spare tire,
if the vehicle has one, even if it is
not being used. Multiple conditions
affect how fast this aging takes
place, including temperatures,
loading conditions, and inflation
pressure maintenance. Tires will
typically need to be replaced due to
wear before they may need to be
replaced due to age. Consult the tire
manufacturer for more information
on when tires should be replaced.
Vehicle Storage
Tires age when stored normally
mounted on a parked vehicle. Park
a vehicle that will be stored for at
least a month in a cool, dry, clean
area away from direct sunlight to
slow aging. This area should be
free of grease, gasoline, or
other substances that can
deteriorate rubber. Parking for an extended period can
cause flat spots on the tires that
may result in vibrations while
driving. When storing a vehicle for
at least a month, remove the tires or
raise the vehicle to reduce the
weight from the tires.
Buying New Tires
GM has developed and matched
specific tires for your vehicle.
The original equipment tires
installed on your vehicle, when it
was new, were designed to meet
General Motors Tire
Performance Criteria
Specification (TPC Spec)
system rating. If you need
replacement tires, GM strongly
recommends that you get tires
with the same TPC Spec rating.
This way, your vehicle will
continue to have tires that are
designed to give the same
performance and vehicle safety,
during normal use, as the
original tires.
GM's exclusive TPC Spec
system considers over a dozen
critical specifications that impact
the overall performance of your
vehicle, including brake system
performance, ride and handling,
traction control, and tire
pressure monitoring
performance. GM's TPC Spec
number is molded onto the tire's
sidewall near the tire size. If the
tires have an all‐season tread
design, the TPC Spec number
will be followed by an MS for
mud and snow. See
Tire
Sidewall Labeling on page 10‑39
for additional information.