2012 GMC SIERRA 1500 tire type

Black plate (55,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-55
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 mean
a light truck 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 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 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
steering, power brakes, power
windows, power seats, and air
conditioning.
Aspect Ratio
:The relationship
of a tire's height to its width.

Black plate (59,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-59
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.
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 9‑16. 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 spare tire,
if the vehicle has one. See
Full-Size Spare Tire on
page 10‑87
for additional
information.
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.
Re-check the tire pressure with
the tire gauge.
Return the valve caps on the
valve stems to prevent leaks
and keep out dirt and moisture.

Black plate (69,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-69
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. SeeTire Sidewall Labeling on
page 10‑52 for additional
information.
GM recommends replacing all the
tires at the same time. 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.
See Tire Inspection on page 10‑65
and Tire Rotation on page 10‑65 for
information on proper tire rotation.
{WARNING
Tires could explode during
improper service. Attempting
to mount or dismount a tire
could cause injury or death.
(Continued)
WARNING (Continued)
Only your dealer or authorized
tire service center should
mount or dismount the tires.
{WARNING
Mixing tires of different sizes,
brands, or types may cause
loss of control of the vehicle,
resulting in a crash or other
vehicle damage. Use the correct
size, brand, and type of tires on
all wheels.
This vehicle may have a different
size spare than the road tires
originally installed on the vehicle.
When new, the vehicle included a
spare tire and wheel assembly
with a similar overall diameter as
the road tires and wheels, so it is
all right to drive on it. The spare (Continued)
WARNING (Continued)
tire was developed for use on this
vehicle and will not affect vehicle
handling.
{WARNING
Using bias-ply tires on the
vehicle may cause the wheel
rim flanges to develop cracks
after many miles of driving.
A tire and/or wheel could fail
suddenly and cause a crash.
Use only radial-ply tires with
the wheels on the vehicle.
If the vehicle tires must be replaced
with a tire that does not have a TPC
Spec number, make sure they are
the same size, load range, speed
rating, and construction (radial) as
the original tires.

Black plate (74,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
10-74 Vehicle Care
Tire Chains
{WARNING
If the vehicle has dual wheels
or P265/65R18, P275/55R20,
LT265/70R17, LT265/70R18,
LT265/60R20, P285/50R20,
P285/45R22 or 285/45R22 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, suspension, or other
vehicle parts. The area damaged
by the tire chains could cause you
to lose control of the vehicle and
you or others may be injured in a
crash.(Continued)
WARNING (Continued)
Use another type of traction
device only if its manufacturer
recommends it for use on the
vehicle and tire size combination
and road conditions. Follow that
manufacturer's instructions. To
help avoid damage to the vehicle,
drive slowly, readjust, or remove
the device if it is contacting the
vehicle, and do not spin the
vehicle's wheels.
If you do find traction devices that
will fit, install them on the rear
tires. Notice:
If the vehicle does not
have dual wheels and has a tire
size other than P265/65R18,
P275/55R20, LT265/70R17,
LT265/70R18, LT265/60R20,
P285/50R20, P285/45R22, or
285/45R22, use tire chains only
where legal and only when you
must. Use chains that are the
proper size for the tires. Install
them on the tires of the rear axle.
Do not use chains on the tires of
the front axle. Tighten them as
tightly as possible with the
ends securely fastened. Drive
slowly and follow the chain
manufacturer's instructions.
If you can hear the chains
contacting the vehicle, stop and
retighten them. If the contact
continues, slow down until it
stops. Driving too fast or
spinning the wheels with chains
on will damage the vehicle.

Black plate (87,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
Vehicle Care 10-87
Full-Size Spare Tire
Your vehicle, when new, had a
fully-inflated spare tire. A spare tire
may lose air over time, so check
its inflation pressure regularly. See
Tire Pressure on page 10‑58and
Vehicle Load Limits on page 9‑16
for information regarding proper tire
inflation and loading your vehicle.
For instruction on how to remove,
install or store a spare tire, see
“Removing the Flat Tire and
Installing the Spare” and“Storing a
Flat or Spare Tire and Tools” under
Tire Changing on page 10‑76. Notice:
If the vehicle has
four-wheel drive and a different
size spare tire is installed, do
not drive in four-wheel drive until
the flat tire is repaired and/or
replaced. The vehicle could be
damaged and the repairs would
not be covered by the warranty.
Never use four-wheel drive when
a different size spare tire is
installed on the vehicle.
Your vehicle may have a different
size spare tire than the road tires
originally installed on your vehicle.
This spare tire was developed for
use on your vehicle, so it is all right
to drive on it. If your vehicle has
four-wheel drive and the different
size spare tire is installed, keep the
vehicle in two-wheel drive. After installing the spare tire on your
vehicle, you should stop as soon as
possible and make sure the spare
tire is correctly inflated. Have the
damaged or flat road tire repaired or
replaced as soon as you can and
installed back onto your vehicle.
This way, the spare tire will be
available in case you need it again.
Do not mix tires and wheels of
different sizes, because they will
not fit. Keep your spare tire and its
wheel together. If your vehicle has a
spare tire that does not match your
vehicle's original road tires and
wheels in size and type, do not
include the spare in the tire rotation.

Black plate (8,1)GMC Sierra Owner Manual - 2012 - CRC - 11/15/11
13-8 Customer Information
Roadside Assistance is not a part of
the New Vehicle Limited Warranty.
GMC and General Motors of
Canada Limited reserve the right to
make any changes or discontinue
the Roadside Assistance program at
any time without notification.
GMC and General Motors of
Canada Limited reserve the right to
limit services or payment to an
owner or driver if they decide the
claims are made too often, or the
same type of claim is made many
times.
Services Provided
.Emergency Fuel Delivery:
Delivery of enough fuel for the
vehicle to get to the nearest
service station.
.Lock‐Out Service:Service to
unlock the vehicle if you are
locked out. A remote unlock
may be available if you have
OnStar
®. For security reasons,
the driver must present
identification before this service
is given.
.Emergency Tow From a Public
Road or Highway: Tow to the
nearest GMC dealer for warranty
service, or if the vehicle was in
a crash and cannot be driven.
Assistance is also given when
the vehicle is stuck in the sand,
mud, or snow.
.Flat Tire Change: Service to
change a flat tire with the spare
tire. The spare tire, if equipped,
must be in good condition and
properly inflated. It is the owner's
responsibility for the repair or
replacement of the tire if it is not
covered by the warranty.
.Battery Jump Start: Service to
jump start a dead battery.
.Trip Routing Service: Detailed
maps of North America when
requested either with the
most direct route or the most
scenic route. Additional travel
information is also available.
Allow three weeks for delivery.
.Trip Interruption Benefits and
Assistance: If your trip is
interrupted due to a warranty
failure, incidental expenses
may be reimbursed during the
5 years/(160 000 km) 100,000 mi
Powertrain warranty period.
Items considered are hotel,
meals, and rental car.
Services Not Included in
Roadside Assistance
.Impound towing caused by
violation of any laws.
.Legal fines.
.Mounting, dismounting,
or changing of snow tires,
chains, or other traction devices.
.Towing or services for vehicles
driven on a non-public road or
highway.