2013 GMC SIERRA tire type

Black plate (52,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
10-52 Vehicle Care
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 (56,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
10-56 Vehicle Care
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 10‑82for 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.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 buildup
and can cause sudden tire failure.
You could have a crash and you
or others could be killed. Some
high-speed rated tires require
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.

Black plate (66,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
10-66 Vehicle Care
{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 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.
Vehicles that have a tire
pressure monitoring system
could give an inaccurate
low-pressure warning if non-TPC
Spec rated tires are installed.
See Tire Pressure Monitor
System on page 10‑57. The Tire and Loading
Information label indicates the
original equipment tires on the
vehicle. See
Vehicle Load Limits
on page 9‑15 for the label
location and more information
about the Tire and Loading
Information label.
Different Size Tires and
Wheels
If wheels or tires are installed that
are a different size than the original
equipment wheels and tires, vehicle
performance, including its braking,
ride and handling characteristics,
stability, and resistance to rollover
may be affected. If the vehicle has
electronic systems such as antilock
brakes, rollover airbags, traction
control, electronic stability control,
or All-Wheel Drive, the performance
of these systems can also be
affected.

Black plate (70,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
10-70 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.
Use another type of traction
device only if its manufacturer
recommends it for use on the
vehicle and tire size combination(Continued)
WARNING (Continued)
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.
If a Tire Goes Flat
It is unusual for a tire to blowout
while driving, especially if the tires
are maintained properly. If air goes
out of a tire, it is much more likely to
leak out slowly. But if there ever is a
blowout, here are a few tips about
what to expect and what to do:
If a front tire fails, the flat tire
creates a drag that pulls the vehicle
toward that side. Take your foot off
the accelerator pedal and grip the
steering wheel firmly. Steer to
maintain lane position, and then
gently brake to a stop, well off the
road, if possible.

Black plate (82,1)GMC Sierra Owner Manual - 2013 - crc - 8/14/12
10-82 Vehicle Care
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. SeeTire
Pressure on page 10‑55 and
Vehicle Load Limits on page 9‑15
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 10‑72.
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.
Jump Starting
For more information about the
vehicle battery, see
Battery on
page 10‑27.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
If the vehicle's battery (or batteries)
has run down, you may want to use
another vehicle and some jumper
cables to start your vehicle. Be sure
to use the following steps to do it
safely.
{WARNING
Batteries can hurt you. They can
be dangerous because:
.They contain acid that can
burn you.
.They contain gas that can
explode or ignite.
.They contain enough
electricity to burn you.
(Continued)