Black plate (51,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
6014662) - 2014 - crc - 8/26/13
Vehicle Care 10-51
Tire Designations
Tire Size
The following examples show
the different parts of a tire size.
Passenger (P-Metric) Tire
(1) 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.
(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 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) 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.
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6014662) - 2014 - crc - 8/26/13
10-52 Vehicle Care
(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. This
does not apply to Goodyear
LT225/75R16 G949 RSA and
Goodyear LT225/75R16 G933
RSD commercial truck tires; see
the dual tire and single tire
maximum load and load range
letter designations on the tire
sidewall.
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.
Aspect 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.
Black plate (55,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
6014662) - 2014 - crc - 8/26/13
Vehicle Care 10-55
determined by tire
manufacturers using
government testing procedures.
The ratings are molded into the
sidewall of the tire. SeeUniform
Tire Quality Grading on
page 10-66.
Vehicle Capacity Weight
:The
number of designated seating
positions multiplied by
68 kg (150 lb) plus the rated
cargo load. See Vehicle Load
Limits on page 9-10.
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 9-10.
Tire Pressure
Tires need the correct amount of
air pressure to operate
effectively.
{Caution
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.
(Continued)
Caution (Continued)
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.
Black plate (56,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
6014662) - 2014 - crc - 8/26/13
10-56 Vehicle Care
For additional information
regarding how much weight the
vehicle can carry, and an
example of the Tire and Loading
Information label, seeVehicle
Load Limits on page 9-10. 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 10-79 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.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
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10-58 Vehicle Care
located on the instrument cluster.
If the warning light comes on, stop
as soon as possible and inflate the
tires to the recommended pressure
shown on the Tire and Loading
Information label. SeeVehicle Load
Limits on page 9-10.
A message to check the pressure in
a specific tire displays in the Driver
Information Center (DIC). The low
tire pressure warning light and the
DIC warning message come on at
each ignition cycle until the tires are
inflated to the correct inflation
pressure. If the vehicle has DIC
buttons, tire pressure levels can be
viewed. For additional information
and details about the DIC operation
and displays, see Driver Information
Center (DIC) on page 5-25 andTire
Messages on page 5-37.
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 9-10, for an example
of the Tire and Loading Information
label and its location. Also see Tire
Pressure on page 10-55.
The TPMS can warn about a low
tire pressure condition but it does
not replace normal tire
maintenance. See Tire Inspection
on page 10-61, Tire Rotation on
page 10-61 andTires on
page 10-46.{Caution
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.
Black plate (61,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
6014662) - 2014 - crc - 8/26/13
Vehicle Care 10-61
10. Set all four tires to therecommended air pressure
level as indicated on the Tire
and Loading Information label.
Tire Inspection
We recommend that the tires,
including the spare tire, if the
vehicle has one, be inspected
for signs of wear or damage at
least once a month.
Replace the tire if:
.The indicators at three or
more places around the tire
can be seen.
.There is 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 mi). See
Maintenance Schedule on
page 11-3.
Tires are rotated to achieve a
uniform wear for all tires. The
first rotation is the most
important.
Any time unusual wear is
noticed, rotate the tires as soon
as possible and check the wheel
alignment. Also check for
damaged tires or wheels. See
When It Is Time for New Tires
on page 10-63 andWheel
Replacement on page 10-68.
Use this rotation pattern when
rotating the tires.
If the vehicle has a compact
spare tire, do not include it in the
tire rotation.
Adjust the front and rear tires to
the recommended inflation
pressure on the Tire and
Loading Information label after
the tires have been rotated. See
Tire Pressure on page 10-55
and Vehicle Load Limits on
page 9-10.
Black plate (64,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
6014662) - 2014 - crc - 8/26/13
10-64 Vehicle Care
Buying New Tires
GM has developed and matched
specific tires for the vehicle. The
original equipment tires installed
were designed to meet General
Motors Tire Performance Criteria
Specification (TPC Spec)
system rating. When
replacement tires are needed,
GM strongly recommends
buying tires with the same TPC
Spec rating.
GM's exclusive TPC Spec
system considers over a dozen
critical specifications that impact
the overall performance of the
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 numberwill be followed by MS for mud
and snow. See
Tire Sidewall
Labeling on page 10-48 for
additional information.
GM recommends replacing worn
tires in complete sets of four (six
for dual rear wheels). 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. If proper rotation and
maintenance have been done,
all four tires (six for dual rear
wheels) should wear out at
about the same time. See Tire
Rotation on page 10-61 for
information on proper tire
rotation. However, if it is
necessary to replace only one
axle set of worn tires, place the
new tires on the rear axle (two
for single rear wheels, four for
dual rear wheels).{Warning
Tires could explode during
improper service. Attempting
to mount or dismount a tire
could cause injury or death.
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
(Continued)
Black plate (65,1)Chevrolet Express Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
6014662) - 2014 - crc - 8/26/13
Vehicle Care 10-65
Warning (Continued)
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 10-56.
The Tire and Loading
Information label indicates the
original equipment tires on the
vehicle. See Vehicle Load Limits
on page 9-10 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.
{Warning
If different sized wheels are used,
there may not be an acceptable
level of performance and safety if
tires not recommended for those
wheels are selected. This
increases the chance of a crash
and serious injury. Only use GM
(Continued)