2009 GMC ACADIA tire size

Tire Sidewall Labeling
Useful information about a tire
is molded into its sidewall. The
examples below show a typical
passenger vehicle tire and a
compact spare tire sidewall.
(A) Tire Size
:The tire size
is a combination of letters and
numbers used to dene aparticular tire’s width, height,
aspect ratio, construction type,
and service description. See the
“Tire Size” illustration later in this
section for more detail.
(B) TPC Spec (Tire
Performance Criteria
Specication)
:Original
equipment tires designed to
GM’s specic tire performance
criteria have a TPC specication
code molded onto the sidewall.
GM’s TPC specications meet
or exceed all federal safety
guidelines.
(C) DOT (Department
of Transportation)
:The
Department of Transportation
(DOT) code indicates that the tire
is in compliance with the U.S.
Department of Transportation
Motor Vehicle Safety Standards.(D) Tire Identication Number
(TIN)
:The letters and numbers
following DOT (Department
of Transportation) code is the
Tire Identication Number (TIN).
The TIN shows the manufacturer
and plant code, tire size, and
date the tire was manufactured.
The TIN is molded onto both
sides of the tire, although
only one side may have the
date of manufacture.
(E) Tire Ply Material
:The type
of cord and number of plies
in the sidewall and under
the tread.
(F) Uniform Tire Quality
Grading (UTQG)
:Tire
manufacturers are required
to grade tires based on three
performance factors: treadwear,
traction, and temperature
resistance. For more information
seeUniform Tire Quality Grading
on page 5-51. Passenger (P-Metric) Tire
Example
5-36 Service and Appearance Care

(G) Maximum Cold Ination
Load Limit:Maximum load that
can be carried and the maximum
pressure needed to support
that load.
(A) Temporary Use Only
:The
compact spare tire or temporary
use tire has a tread life of
approximately 3,000 miles
(5 000 km) and should not be
driven at speeds over 65 mph
(105 km/h). The compact spare
tire is for emergency use when aregular road tire has lost air and
gone at. If your vehicle has a
compact spare tire, seeCompact
Spare Tire on page 5-81andIf a
Tire Goes Flat on page 5-55.
(B) Tire Ply Material
:The type
of cord and number of plies in the
sidewall and under the tread.
(C) Tire Identication Number
(TIN)
:The letters and numbers
following the DOT (Department
of Transportation) code is the
Tire Identication Number (TIN).
The TIN shows the manufacturer
and plant code, tire size, and
date the tire was manufactured.
The TIN is molded onto both
sides of the tire, although only
one side may have the date of
manufacture.
(D) Maximum Cold Ination
Load Limit
:Maximum load
that can be carried and
the maximum pressure needed
to support that load.(E) Tire Ination
:The
temporary use tire or compact
spare tire should be inated
to 60 psi (420 kPa). For
more information on tire
pressure and ination see
Inflation - Tire Pressure on
page 5-41.
(F) Tire Size
:A combination
of letters and numbers dene a
tire’s width, height, aspect ratio,
construction type, and service
description. The letter T as the
rst character in the tire size
means the tire is for temporary
use only.
(G) TPC Spec (Tire
Performance Criteria
Specication)
:Original
equipment tires designed to
GM’s specic tire performance
criteria have a TPC specication
code molded onto the sidewall.
GM’s TPC specications
meet or exceed all federal
safety guidelines. Compact Spare Tire Example
Service and Appearance Care 5-37

Tire Size
The following illustration shows
an example of a typical
passenger vehicle tire size.
(A) Passenger (P-Metric) Tire
:The United States version of
a metric tire sizing system. The
letter P as the rst 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 60, as shown in
item C of the illustration, it would
mean that the tire’s sidewall is
60 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
range and speed rating of the
tire. The load index represents
the load carry capacity a tire is
certied to carry. The load index
can range from 1 to 279. The
speed rating is the maximum
speed a tire is certied to carry
a load. Speed ratings range
fromAtoZ.
Tire Terminology and
Denitions
Air Pressure:The amount
of air inside the tire pressing
outward on each square inch
of the tire. Air pressure is
expressed in pounds per square
inch (psi) or kilopascal (kPa).
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.
5-38 Service and Appearance Care

Vehicle Capacity Weight:The
number of designated seating
positions multiplied by 150 lbs
(68 kg) plus the rated cargo load.
SeeLoading the Vehicle on
page 4-16.
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’s
capacity weight and the original
equipment tire size and
recommended ination pressure.
See “Tire and Loading
Information Label” underLoading
the Vehicle on page 4-16.
Ination - Tire Pressure
Tires need the correct amount
of air pressure to operate
effectively.
Notice:Do not let anyone tell
you that under-ination or
over-ination is all right. It is
not. If your tires do not have
enough air (under-ination),
you can get the following:
Too much exing
Too much heat
Tire overloading
Premature or irregular wear
Poor handling
Reduced fuel economy
If your tires have too much air
(over-ination), you can get
the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road
hazardsA vehicle specic Tire and
Loading Information label is
attached to your vehicle. This
label shows your vehicle’s
original equipment tires and the
correct ination pressures for
your tires when they are cold.
The recommended cold tire
ination pressure, shown on the
label, is the minimum amount of
air pressure needed to support
your vehicle’s maximum load
carrying capacity.
For additional information
regarding how much weight
your vehicle can carry, and an
example of the Tire and Loading
Information label, seeLoading
the Vehicle on page 4-16. How
you load your vehicle affects
vehicle handling and ride
comfort. Never load your vehicle
with more weight than it was
designed to carry.
Service and Appearance Care 5-41

When to Check
Check your tires once a month
or more. Do not forget to check
the compact spare tire, if the
vehicle has one. It should be at
60 psi (420 kPa). For additional
information regarding the
compact spare tire, seeCompact
Spare Tire on page 5-81.
How to Check
Use a good quality pocket-type
gage to check tire pressure.
You cannot tell if your tires are
properly inated simply by
looking at them. Radial tires may
look properly inated even when
they are under-inated. Check
the tire’s ination pressure when
the tires are cold. Cold means
your vehicle has been sitting for
at least three hours or driven
no more than 1 mile (1.6 km).Remove the valve cap from the
tire valve stem. Press the tire
gage rmly onto the valve to get
a pressure measurement. If the
cold tire ination pressure
matches the recommended
pressure on the Tire and Loading
Information label, no further
adjustment is necessary. If the
ination pressure is low, add air
until you reach the recommended
amount.
If you overll the tire, release air
by pushing on the metal stem
in the center of the tire valve.
Re-check the tire pressure with
the tire gage.
Be sure to put the valve caps
back on the valve stems.
They help prevent leaks by
keeping 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 vehicle’s 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 inated to the
ination pressure recommended by
the vehicle manufacturer on the
vehicle placard or tire ination
pressure label. (If your vehicle has
tires of a different size than the size
indicated on the vehicle placard or
tire ination pressure label, you
should determine the proper tire
ination 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 signicantly under-inated.
5-42 Service and Appearance Care

Changes or modications to
this system by other than an
authorized service facility could void
authorization to use this equipment.
Tire Pressure Monitor
Operation
This vehicle may have a Tire
Pressure Monitor System (TPMS).
The TPMS is designed to warn
the driver when a low tire pressure
condition exists. TPMS sensors
are mounted onto each tire
and wheel assembly, excluding the
spare tire and wheel assembly,
if the vehicle has one. The TPMS
sensors monitor the air pressure in
the vehicle’s tires and transmits
the tire pressure readings to
a receiver located in the vehicle.When a low tire pressure condition
is detected, the TPMS illuminates
the low tire pressure warning
light located on the instrument
panel cluster.
At the same time a message to
check the pressure in a specic tire
appears on the Driver Information
Center (DIC) display. The low tire
pressure warning light and the DIC
warning message come on at each
ignition cycle until the tires are
inated to the correct ination
pressure. Using the DIC, tire
pressure levels can be viewed by
the driver. For additional information
and details about the DIC operation
and displays seeDIC Operation and
Displays (With DIC Buttons) on
page 3-46orDIC Operation and
Displays (Without DIC Buttons) on
page 3-51andDIC Warnings and
Messages on page 3-56.The low tire pressure warning light
may come on in cool weather
when the vehicle is rst started, and
then turn off as you start to drive.
This could be an early indicator that
the air pressure in the tire(s) are
getting low and need to be inated
to the proper pressure.
A Tire and Loading Information
label, attached to your vehicle,
shows the size of your vehicle’s
original equipment tires and
the correct ination pressure for
your vehicle’s tires when they
are cold. SeeLoading the Vehicle
on page 4-16, for an example of
the Tire and Loading Information
label and its location on your
vehicle. Also seeInflation - Tire
Pressure on page 5-41.
Your vehicle’s TPMS can warn you
about a low tire pressure condition
but it does not replace normal tire
maintenance. SeeTire Inspection
and Rotation on page 5-47andTires
on page 5-35.
5-44 Service and Appearance Care

You need new 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.
The rubber in tires degrades over
time, even if they are not being
used. This is also true for the spare
tire, if the vehicle has one. Multiple
conditions affect how fast this
aging takes place, including
temperatures, loading conditions,
and ination pressure maintenance.With proper care and maintenance
tires typically wear out before
they degrade due to age. If you are
unsure about the need to replace
the tires as they get older, consult
the tire manufacturer for more
information.
Buying New Tires
GM has developed and matched
specic tires for your vehicle. The
original equipment tires installed
on your vehicle, when it was new,
were designed to meet General
Motors Tire Performance Criteria
Specication (TPC Spec) system
rating. If you need replacement
tires, GM strongly recommends
that you get tires with the same
TPC Spec rating. This way, your
vehicle will continue to have tires
that are designed to give the
same performance and vehicle
safety, during normal use, as the
original tires.GM’s exclusive TPC Spec
system considers over a dozen
critical specications that impact
the overall performance of your
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 an MS for mud and snow.
SeeTire Sidewall Labeling
on page 5-36for additional
information.
GM recommends replacing tires
in sets of four. This is because
uniform tread depth on all tires
will help keep your vehicle
performing most like it did
when the tires were new.
Service and Appearance Care 5-49

Replacing less than a full set of
tires can affect the braking and
handling performance of your
vehicle. SeeTire Inspection
and Rotation on page 5-47for
information on proper tire
rotation.
{CAUTION
Mixing tires could cause you
to lose control while driving.
If you mix tires of different
sizes, brands, or types (radial
and bias-belted tires), the
vehicle may not handle
properly, and you could have a
crash. Using tires of different
sizes, brands, or types may
also cause damage to your
vehicle. Be sure to use the
correct size, brand, and type of
tires on all wheels. It is all right
to drive with your compact
spare temporarily, as it was
developed for use on your
vehicle. SeeCompact Spare
Tire on page 5-81.
{CAUTION
If you use bias-ply tires on the
vehicle, the wheel rim anges
could develop cracks after
many miles of driving. A tire
and/or wheel could fail
suddenly, causing a crash.
Use only radial-ply tires with
the wheels on the vehicle.
If you must replace your
vehicle’s tires with those that do
not have a TPC Spec number,
make sure they are the same
size, load range, speed rating,
and construction type (radial
and bias-belted tires) as your
vehicle’s 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
on your vehicle. Non-TPCSpec rated tires may give a
low-pressure warning that is
higher or lower than the proper
warning level you would get with
TPC Spec rated tires. SeeTire
Pressure Monitor System on
page 5-42.
Your vehicle’s original equipment
tires are listed on the Tire and
Loading Information Label.
SeeLoading the Vehicle on
page 4-16, for more information
about the Tire and Loading
Information Label and its location
on your vehicle.
Different Size Tires and
Wheels
If you add wheels or tires that are
a different size than your original
equipment wheels and tires, this
could affect the way your vehicle
performs, including its braking,
ride and handling characteristics,
stability, and resistance to rollover.
5-50 Service and Appearance Care