Black plate (44,1)GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-6081485) - 2014 - CRC - 12/6/13
10-44 Vehicle Care
(1) Passenger (P-Metric)
Tire
:The United States version
of a metric tire sizing system.
The letter P as the first
character in the tire size means
a passenger vehicle tire
engineered to standards set by
the U.S. Tire and Rim
Association.
(2) Tire Width
:The three-digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.
(3) Aspect Ratio
:A two-digit
number that indicates the tire
height-to-width measurements.
For example, if the tire size
aspect ratio is 60, as shown in
item 3 of the illustration, it would
mean that the tire's sidewall is
60 percent as high as it is wide.
(4) Construction Code
:A
letter code is used to indicate
the type of ply construction in
the tire. 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) Rim Diameter
:Diameter of
the wheel in inches.
(6) Service Description
:
These characters represent the
load index and speed rating of
the tire. The load index
represents the load carrying
capacity a tire is certified to
carry. The speed rating is the
maximum speed a tire is
certified to carry a load.
Tire Terminology and
Definitions
Air Pressure:The amount of
air inside the tire pressing
outward on each square inch
of the tire. Air pressure is
expressed in kPa (kilopascal)
or psi (pounds per square inch). Accessory Weight
:The
combined weight of optional
accessories. Some examples
of optional accessories are
automatic transmission, power
windows, power seats, and air
conditioning.
Aspect Ratio
:The relationship
of a tire's height to its width.
Belt
:A rubber coated layer of
cords 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.
Black plate (45,1)GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-6081485) - 2014 - CRC - 12/6/13
Vehicle Care 10-45
Cold Tire Pressure:The
amount of air pressure in a tire,
measured in kPa (kilopascal)
or psi (pounds per square inch)
before a tire has built up heat
from driving. See Tire Pressure
on page 10-47.
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 9-14.
GAWR FRT
:Gross Axle
Weight Rating for the front axle.
See Vehicle Load Limits on
page 9-14.
GAWR RR
:Gross Axle Weight
Rating for the rear axle. See
Vehicle Load Limits on
page 9-14.
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 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 lb).
See Vehicle Load Limits on
page 9-14.
Black plate (47,1)GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-6081485) - 2014 - CRC - 12/6/13
Vehicle Care 10-47
The ratings are molded into the
sidewall of the tire. SeeUniform
Tire Quality Grading on
page 10-57.
Vehicle Capacity Weight
:The
number of designated seating
positions multiplied by
68 kg (150 lb) plus the rated
cargo load. See Vehicle Load
Limits on page 9-14.
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
capacity weight and the
original equipment tire size
and recommended inflation
pressure. See “Tire and Loading
Information Label” underVehicle
Load Limits on page 9-14.
Tire Pressure
Tires need the correct amount of
air pressure to operate
effectively.
{Caution
Neither tire underinflation
nor overinflation is good.
Underinflated tires, or tires
that do not have enough air,
can result in:
.Tire overloading and
overheating which could
lead to a blowout.
.Premature or
irregular wear.
.Poor handling.
.Reduced fuel economy.
(Continued)
Caution (Continued)
Overinflated tires, or tires that
have too much air, can
result in:
.Unusual wear.
.Poor handling.
.Rough ride.
.Needless damage from
road hazards.
The Tire and Loading
Information label on the vehicle
indicates the original equipment
tires and the correct cold tire
inflation pressures. The
recommended pressure is the
minimum air pressure needed to
support the vehicle's maximum
load carrying capacity. See
Vehicle Load Limits on
page 9-14.
Black plate (48,1)GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-6081485) - 2014 - CRC - 12/6/13
10-48 Vehicle Care
How the vehicle is loaded
affects vehicle handling and ride
comfort. Never load the vehicle
with more weight than it was
designed to carry.
When to Check
Check the tires once a month or
more. Do not forget the compact
spare, if the vehicle has one.
The cold compact spare tire
pressure should be at 420 kPa
(60 psi). SeeCompact Spare
Tire on page 10-68.
How to Check
Use a good quality pocket-type
gauge to check tire pressure.
Proper tire inflation cannot be
determined by looking at the tire.
Check the tire inflation pressure
when the tires are cold, meaning
the vehicle has not been driven
for at least three hours or no
more than 1.6 km (1 mi). 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 the recommended
pressure is reached. If the
inflation pressure is high, press
on the metal stem in the center
of the tire valve to release air.
Recheck the tire pressure with
the tire gauge.
Return the valve caps on the
valve stems to prevent leaks
and keep out dirt and moisture.Tire Pressure Monitor
System
The Tire Pressure Monitor System
(TPMS) uses radio and sensor
technology to check tire pressure
levels. The TPMS sensors monitor
the air pressure in your tires and
transmit tire pressure readings to a
receiver located in the vehicle.
Each tire, including the spare (if
provided), should be checked
monthly when cold and inflated to
the inflation pressure recommended
by the vehicle manufacturer on the
vehicle placard or tire inflation
pressure label. (If your vehicle has
tires of a different size than the size
indicated on the vehicle placard or
tire inflation pressure label, you
should determine the proper tire
inflation pressure for those tires.)
Black plate (55,1)GMC Terrain/Terrain Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-6081485) - 2014 - CRC - 12/6/13
Vehicle Care 10-55
equipped, be replaced after six
years, regardless of tread wear. The
tire manufacture date is the last four
digits of the DOT Tire Identification
Number (TIN) which is molded into
one side of the tire sidewall. The
first two digits represent the week
(01–52) and the last two digits, the
year. For example, the third week of
the year 2010 would have a
four-digit DOT date of 0310.
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 forat 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 the vehicle. The
original equipment tires installed
were designed to meet General
Motors Tire Performance Criteria
Specification (TPC Spec)
system rating. When
replacement tires are needed,
GM strongly recommends
buying tires with the same TPC
Spec rating.
GM's exclusive TPC Spec
system considers over a dozen
critical specifications that impact
the overall performance of the
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 MS for mud
and snow. See
Tire Sidewall
Labeling on page 10-41.
GM recommends replacing worn
tires in complete sets of four.
Uniform tread depth on all tires
will help to maintain the
performance of the vehicle.
Braking and handling
performance may be adversely
affected if all the tires are not
replaced at the same time.
If proper rotation and
maintenance have been done,
all four tires should wear out at
about the same time. See Tire
Rotation on page 10-53.
However, if it is necessary to
replace only one axle set of
worn tires, place the new tires
on the rear axle.