GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/15/18
364 Vehicle Care (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.
Light Truck (LT-Metric) Tire
(1) Light Truck (LT-Metric)
Tire :
The United States version
of a metric tire sizing system.
The letters LT as the first two
characters in the tire size mean
a light truck 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 75, as shown in
item 3 of the light truck
(LT-Metric) tire illustration, it
would mean that the tire's
sidewall is 75 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) Load Range :
Load Range. (7) Service Description :
The
service description indicates the
load index and speed rating of a
tire. If two numbers are given as
in the example, 120/116, then
this represents the load index for
single versus dual wheel usage
(single/dual). 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.
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/15/18
Vehicle Care 365Aspect 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.
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
0 367 . 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
0 209 .
GAWR FRT :
Gross Axle Weight
Rating for the front axle. See
Vehicle Load Limits 0 209 . GAWR RR :
Gross Axle Weight
Rating for the rear axle. See
Vehicle Load Limits 0 209 .
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.
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/15/18
366 Vehicle Care 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 0 209 .
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 0 367 and
Vehicle Load Limits 0 209 .
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.
Treadwear Indicators :
Narrow
bands, sometimes called wear
bars, that show across the tread
of a tire when only 1.6 mm
(1/16 in) of tread remains. See
When It Is Time for New Tires
0 377 .
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
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/15/18
Vehicle Care 367government testing procedures.
The ratings are molded into the
sidewall of the tire. See Uniform
Tire Quality Grading 0 380 .
Vehicle Capacity Weight :
The
number of designated seating
positions multiplied by
68 kg (150 lb) plus the rated
cargo load. See Vehicle Load
Limits 0 209 .
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 ” under Vehicle
Load Limits 0 209 . Tire Pressure Tires need the correct amount of
air pressure to operate
effectively.
{ Warning
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.
Overinflated tires, or tires that
have too much air, can
result in:
.
Unusual wear.
(Continued) Warning (Continued) .
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.
For additional information
regarding how much weight the
vehicle can carry, and an
example of the Tire and Loading
Information label, see Vehicle
Load Limits 0 209 . How the
vehicle is loaded affects vehicle
handling and ride comfort. Never
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/15/18
382 Vehicle Care Some aluminum wheels can be
repaired. See your dealer if any of
these conditions exist.
Your dealer will know the kind of
wheel that is needed.
Each new wheel should have the
same load-carrying capacity,
diameter, width, offset and be
mounted the same way as the one it
replaces.
Replace wheels, wheel bolts, wheel
nuts, or Tire Pressure Monitor
System (TPMS) sensors with new
GM original equipment parts.
{ WarningUsing the wrong replacement
wheels, wheel bolts, or wheel
nuts can be dangerous. It could
affect the braking and handling of
the vehicle. Tires can lose air,
and cause loss of control, causing
a crash. Always use the correct
wheel, wheel bolts, and wheel
nuts for replacement. CautionThe wrong wheel can also cause
problems with bearing life, brake
cooling, speedometer or
odometer calibration, headlamp
aim, bumper height, vehicle
ground clearance, and tire or tire
chain clearance to the body and
chassis.
Whenever a wheel, wheel bolt,
or wheel nut is replaced on a dual
wheel setup, check the wheel nut
torque after 160,1 600, and
10 000 km (100,1,000, and
6,000 mi) of driving. For proper
torque, see “ Wheel Nut Torque ”
under Capacities and Specifications
0 430 .
See If a Tire Goes Flat 0 383 for
more information. Used Replacement Wheels
{ WarningReplacing a wheel with a used
one is dangerous. How it has
been used or how far it has been
driven may be unknown. It could
fail suddenly and cause a crash.
When replacing wheels, use a
new GM original equipment
wheel.
Tire Chains
{ WarningIf the vehicle has LT265/70R17,
LT275/65R18, 275/60R20, or 275/
50R22 size tires, do not use tire
chains. They can damage the
vehicle because there is not
enough clearance. Tire chains
used on a vehicle without the
proper amount of clearance can
cause damage to the brakes,
(Continued)