2011 GMC SIERRA tire size

Black plate (61,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-61
Tire Designations
Tire Size
The following examples show
the different parts of a tire size.
Passenger (P‐Metric) Tire
(A) 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.
(B) Tire Width
:The three‐digit
number indicates the tire section
width in millimeters from
sidewall to sidewall. (C) 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 C of the tire illustration,
it would mean that the tire's
sidewall is 75 percent as high
as it is wide.
(D) 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.
(E) Rim Diameter
:Diameter of
the wheel in inches. (F) 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
(A) 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 means
a light truck tire engineered to
standards set by the U.S. Tire
and Rim Association.

Black plate (62,1)GMC Sierra Owner Manual - 2011
10-62 Vehicle Care
(B) Tire Width:The three‐digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.
(C) 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 C 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.
(D) 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. (E) Rim Diameter
:Diameter of
the wheel in inches.
(F) Load Range
:Load Range.
(G) 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 psi (pounds per
square inch) or kPa (kilopascal). Accessory Weight
:This
means the combined weight
of optional accessories.
Some examples of optional
accessories are, automatic
transmission, power steering,
power brakes, 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 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.

Black plate (65,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-65
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 on page 10‑76. 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 10‑80.
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 9‑25. 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 9‑25.

Black plate (66,1)GMC Sierra Owner Manual - 2011
10-66 Vehicle Care
Tire Pressure
Tires need the correct amount
of air pressure to operate
effectively.
Notice:Neither tire
underinflation nor
overinflation is good.
Underinflated tires, or
tires that do not have
enough air, can result in:
.Tire overloading and
over-heating 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.
.Poor handling.
.Rough ride.
.Needless damage from
road hazards.
A vehicle-specific Tire and
Loading Information label
is attached to the vehicle.
This label shows the vehicle's
original equipment tires and the
correct inflation pressures for
the 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 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 on page 9‑25.
How you load the vehicle
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 to check the
pressure of the spare tire, if the
vehicle has one. See Full-Size
Spare Tire on page 10‑97 for
additional information.

Black plate (67,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-67
How to Check
Use a good quality pocket-type
gauge to check tire pressure.
You cannot tell if the 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
the 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 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.
Recheck the tire pressure with
the tire gauge.
Be sure to put the valve caps
back on the valve stems.
They help prevent leaks by
keeping out dirt and moisture.
Tire Pressure for
High-Speed Operation
{WARNING
Driving at high speeds,
160 km/h (100 mph) or higher,
puts an additional strain on tires.
Sustained high-speed driving
causes excessive heat build up
and can cause sudden tire failure.
You could have a crash and you
or others could be killed. Some
high-speed rated tires require
(Continued)
WARNING (Continued)
inflation pressure adjustment
for high speed operation. When
speed limits and road conditions
are such that a vehicle can be
driven at high speeds, make sure
the tires are rated for high speed
operation, in excellent condition,
and set to the correct cold tire
inflation pressure for the
vehicle load.
Vehicles with P265/70R17 or
P275/55R20 size tires require
inflation pressure adjustment
when driving the vehicle at speeds
of 160 km/h (100 mph) or higher.
Set the cold tire inflation pressure
to 20 kPa (3 psi) above the
recommended cold tire pressure
shown on the Tire and Loading
Information label.

Black plate (68,1)GMC Sierra Owner Manual - 2011
10-68 Vehicle Care
When you end this high‐speed
driving, return the tires to the cold
inflation pressure shown on the
Tire and Loading Information
label. SeeVehicle Load Limits on
page 9‑25 andTire Pressure on
page 10‑66.
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.)
As an added safety feature, your
vehicle has been equipped with a
tire pressure monitoring system
(TPMS) that illuminates a low
tire pressure telltale when one or
more of your tires is significantly
under‐inflated.
Accordingly, when the low tire
pressure telltale illuminates, you
should stop and check your tires as
soon as possible, and inflate them
to the proper pressure. Driving on
a significantly under‐inflated tire
causes the tire to overheat and can
lead to tire failure. Under‐inflation
also reduces fuel efficiency and
tire tread life, and may affect the
vehicle's handling and stopping
ability.Please note that the TPMS is
not a substitute for proper tire
maintenance, and it is the driver's
responsibility to maintain correct tire
pressure, even if under‐inflation
has not reached the level to trigger
illumination of the TPMS low tire
pressure telltale.
Your vehicle has also been
equipped with a TPMS malfunction
indicator to indicate when the
system is not operating properly.
The TPMS malfunction indicator is
combined with the low tire pressure
telltale. When the system detects a
malfunction, the telltale will flash for
approximately one minute and then
remain continuously illuminated.
This sequence will continue upon
subsequent vehicle start‐ups as
long as the malfunction exists.

Black plate (70,1)GMC Sierra Owner Manual - 2011
10-70 Vehicle Care
For additional information and
details about the DIC operation and
displays, seeDriver Information
Center (DIC) on page 5‑33 and
Tire Messages on page 5‑49.
The low tire pressure warning light
may come on in cool weather when
the vehicle is first started, and then
turn off as the vehicle is driven.
This could be an early indicator that
the air pressure is getting low and
needs to be inflated to the proper
pressure.
A Tire and Loading Information
label shows the size of the original
equipment tires and the correct
inflation pressure for the tires when
they are cold. See Vehicle Load
Limits on page 9‑25, for an example
of the Tire and Loading Information
label and its location. Also see
Tire Pressure on page 10‑66. The TPMS can warn about a
low tire pressure condition but
it does not replace normal tire
maintenance. See
Tire Inspection
on page 10‑73, Tire Rotation on
page 10‑73 andTires on
page 10‑57.
Notice: Tire sealant materials are
not all the same. A non-approved
tire sealant could damage the
TPMS sensors. TPMS sensor
damage caused by using
an incorrect tire sealant is
not covered by the vehicle
warranty. Always use only
the GM-approved tire sealant
available through your dealer
or included in the vehicle.TPMS Malfunction Light and
Message
The TPMS will not function properly
if one or more of the TPMS sensors
are missing or inoperable. When
the system detects a malfunction,
the low tire pressure warning light
flashes for about one minute and
then stays on for the remainder of
the ignition cycle. A DIC warning
message also displays. The
malfunction light and DIC warning
message come on at each ignition
cycle until the problem is corrected.
Some of the conditions that can
cause these to come on are:
.One of the road tires has been
replaced with the spare tire.
The spare tire does not have a
TPMS sensor. The malfunction
light and the DIC message
should go off after the road
tire is replaced and the sensor
matching process is performed
successfully. See "TPMS Sensor
Matching Process" later in this
section.

Black plate (73,1)GMC Sierra Owner Manual - 2011
Vehicle Care 10-73
Tire Inspection
We recommend that you
regularly inspect the vehicle's
tires, including the spare tire,
if the vehicle has one, for signs
of wear or damage at least once
a month.
Always remove the tires if any
of the following statements
are true:
.You can see the indicators at
three or more places around
the tire.
.You can see cord or fabric
showing through the tire's
rubber.
.The tread or sidewall is
cracked, cut, or snagged
deep enough to show cord
or fabric.
.The tire has a bump, bulge,
or split.
.The tire has a puncture, cut,
or other damage that cannot
be repaired well because of
the size or location of the
damage.
Tire Rotation
Tires should be rotated every
12 000 km (7,500 miles).
SeeScheduled Maintenance on
page 11‑2.
The purpose of a regular tire
rotation is to achieve a uniform
wear for all tires on the vehicle.
This will ensure that your vehicle
continues to perform most like it
did when the tires were new.
Any time you notice unusual
wear, rotate your tires as soon
as possible and check wheel
alignment. Also check for
damaged tires or wheels. See
When It Is Time for New
Tires on page 10‑76 andWheel
Replacement on page 10‑82.
If your vehicle has dual rear
wheels, also see Dual Tire
Rotation on page 10‑75.
If your vehicle has single rear
wheels and the tread design for
the front tires is the same as
the rear tires, use the rotation
pattern shown here when
rotating the tires.