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 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.
Bead
:The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the rim.
Bias Ply Tire
:A pneumatic tire in which the plies
are laid at alternate angles less than 90 degrees
to the centerline of the tread. Cold Tire Pressure
:The amount of air pressure
in a tire, measured in pounds per square inch (psi)
or kilopascals (kPa) before a tire has built up heat
from driving. See Inflation - Tire Pressure
on
page 7‑64
.
Curb Weight
:The weight of a motor vehicle with
standard and optional equipment including the
maximum capacity of fuel, oil, and coolant, but
without passengers and cargo.
DOT Markings
:A code molded into the sidewall
of a tire signifying that the tire is in compliance
with the U.S. Department of Transportation (DOT)
motor vehicle safety standards. The DOT code
includes the Tire Identification Number (TIN), an
alphanumeric designator which can also identify
the tire manufacturer, production plant, brand, and
date of production.
GVWR
:Gross Vehicle Weight Rating.
See Loading the Vehicle
on page 6‑32.
GAWR FRT
:Gross Axle Weight Rating for the
front axle. See Loading the Vehicle
on page 6‑32.
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GAWR RR:Gross Axle Weight Rating for the rear
axle. See Loading the Vehicle
on page 6‑32.
Intended Outboard Sidewall
:The side of an
asymmetrical tire, that must always face outward
when mounted on a vehicle.
Kilopascal (kPa)
:The metric unit for air
pressure.
Light Truck (LT‐Metric) Tire
:A tire used on light
duty trucks and some multipurpose passenger
vehicles.
Load Index
:An assigned number ranging from
1 to 279 that corresponds to the load carrying
capacity of a tire.
Maximum Inflation Pressure
:The maximum
air pressure to which a cold tire can be inflated.
The maximum air pressure is molded onto the
sidewall.
Maximum Load Rating
:The load rating for a tire
at the maximum permissible inflation pressure for
that tire.
Maximum Loaded Vehicle Weight
:The sum of
curb weight, accessory weight, vehicle capacity
weight, and production options weight. Normal Occupant Weight
:The number of
occupants a vehicle is designed to seat multiplied
by 150 lbs (68 kg). See Loading the Vehicle
on
page 6‑32
.
Occupant Distribution
:Designated seating
positions.
Outward Facing Sidewall
:The side of an
asymmetrical tire that has a particular side that
faces outward when mounted on a vehicle.
The side of the tire that contains a whitewall,
bears white lettering, or bears manufacturer,
brand, and/or model name molding that is higher
or deeper than the same moldings on the other
sidewall of the tire.
Passenger (P-Metric) Tire
:A tire used on
passenger cars and some light duty trucks and
multipurpose vehicles.
Recommended Inflation Pressure
:Vehicle
manufacturer's recommended tire inflation
pressure as shown on the tire placard.
See Inflation - Tire Pressure
on page 7‑64
andLoading the Vehicleon page 6‑32.
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Radial Ply Tire:A pneumatic tire in which the ply
cords that extend to the beads are laid at
90 degrees to the centerline of the tread.
Rim
:A metal support for a tire and upon which
the tire beads are seated.
Sidewall
:The portion of a tire between the tread
and the bead.
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 1/16 inch (1.6 mm) of tread
remains. See When It Is Time for New Tires
on
page 7‑71
. 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 7‑74.
Vehicle Capacity Weight
:The number of
designated seating positions multiplied by 150 lbs
(68 kg) plus the rated cargo load. See Loading the
Vehicle
on page 6‑32.
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 inflation pressure. See “Tire and
Loading Information Label” underLoading the
Vehicle
on page 6‑32.
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Inflation - Tire Pressure
Tires need the correct amount of air pressure to
operate effectively.
Notice:Do not let anyone tell you that
under‐inflation or over‐inflation is all right.
It is not. If your tires do not have enough air
(under‐inflation), you can get the following:
.Too much flexing
.Too much heat
.Tire overloading
.Premature or irregular wear
.Poor handling
.Reduced fuel economy
If your tires have too much air (over‐inflation),
you can get the following:
.Unusual wear
.Poor handling
.Rough ride
.Needless damage from road hazards A vehicle specific Tire and Loading Information
label is attached to your vehicle. This label shows
your vehicle's original equipment tires and the
correct inflation pressures for your 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 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, see
Loading the Vehicle
on page 6‑32. How you load
your vehicle affects vehicle handling and ride
comfort. Never load your vehicle with more weight
than it was designed to carry.
When to Check
Check your tires once a month or more.
Do not forget to check the pressure of the spare
tire. See Spare Tire
on page 7‑96for additional
information.
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How to Check
Use a good quality pocket-type gage to check tire
pressure. You cannot tell if your tires are properly
inflated simply by looking at them. Radial tires
may look properly inflated even when they are
underinflated. Check the tire's inflation 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 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 gage.
Be sure to put the valve caps back on the valve
stems. They help prevent leaks by keeping out dirt
and moisture.
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
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.
If your vehicle has P265/65R18 or P285/45R22 size
tires and you will be driving at high speeds, speeds of
100 mph (160 km/h) or higher, set the cold inflation
pressure to 3 psi (20 kPa) above the recommended tire
pressure shown on the Tire and Loading Information
Label. When you end this high‐speed driving, return the
tires to the cold inflation pressure shown on the Tire and
Loading Information label. See Loading the Vehicle
on
page 6‑32and Inflation - Tire Pressure on page 7‑64.
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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 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.
When the malfunction indicator is illuminated, the
system may not be able to detect or signal low tire
pressure as intended. TPMS malfunctions may occur
for a variety of reasons, including the installation of
replacement or alternate tires or wheels on the vehicle
that prevent the TPMS from functioning properly.
Always check the TPMS malfunction telltale after
replacing one or more tires or wheels on your vehicle to
ensure that the replacement or alternate tires and
wheels allow the TPMS to continue to function properly.
See
Tire Pressure Monitor Operation
on page 7‑67for
additional information.
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Federal Communications Commission
(FCC) and Industry and Science Canada
SeeRadio Frequency Statementon page 9‑20for
information regarding Part 15 of the Federal
Communications Commission (FCC) Rules and
RSS-210/211 of Industry and Science Canada.
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. 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
specific 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 inflated to the correct inflation
pressure. Using the DIC, tire pressure levels can be
viewed by the driver. For additional information and
details about the DIC operation and displays see
DIC
Operation and Displays
on page 4‑40and DIC
Warnings and Messages on page 4‑48.
The low tire pressure warning light may come on in cool
weather when the vehicle is first 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 inflated 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 inflation pressure for
your vehicle's tires when they are cold. See Loading the
Vehicle
on page 6‑32, for an example of the Tire and
Loading Information label and its location on your
vehicle. Also see Inflation - Tire Pressure on page 7‑64.
Your vehicle's TPMS can warn you about a low tire
pressure condition but it does not replace normal tire
maintenance. See Tire Inspection and Rotation
on
page 7‑70and Tires on page 7‑57.
Notice: Liquid tire sealants could damage the Tire
Pressure Monitor System (TPMS) sensors. Sensor
damage caused by using a tire sealant is not
covered by your warranty. Do not use liquid tire
sealants.
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TPMS Sensor Matching Process
Each TPMS sensor has a unique identification code.
Any time you rotate your vehicle's tires or replace one
or more of the TPMS sensors, the identification codes
will need to be matched to the new tire/wheel position.
The sensors are matched to the tire/wheel positions in
the following order: driver side front tire, passenger
side front tire, passenger side rear tire, and driver
side rear tire using a TPMS diagnostic tool. See your
dealer/retailer for service.
The TPMS sensors can also be matched to each
tire/wheel position by increasing or decreasing the tire's
air pressure. If increasing the tire's air pressure, do not
exceed the maximum inflation pressure indicated on the
tire's sidewall.
To decrease air-pressure out of a tire you can use the
pointed end of the valve cap, a pencil-style air pressure
gage, or a key.
You have two minutes to match the first tire/wheel
position, and five minutes overall to match all four
tire/wheel positions. If it takes longer than two minutes,
to match the first tire and wheel, or more than
five minutes to match all four tire and wheel positions
the matching process stops and you need to start over.The TPMS sensor matching process is outlined below:
1. Set the parking brake.
2. Turn the ignition switch to ON/RUN with the engine off.
3. Press the Remote Keyless Entry (RKE) transmitter's lock and unlock buttons at the same
time for approximately five seconds. The horn
sounds twice to signal the receiver is in relearn
mode and TIRE LEARNING ACTIVE message
displays on the DIC screen.
4. Start with the driver side front tire.
5. Remove the valve cap from the valve cap stem. Activate the TPMS sensor by increasing or
decreasing the tire's air pressure for five seconds,
or until a horn chirp sounds. The horn chirp, which
may take up to 30 seconds to sound, confirms that
the sensor identification code has been matched to
this tire and wheel position.
6. Proceed to the passenger side front tire, and repeat the procedure in Step 5.
7. Proceed to the passenger side rear tire, and repeat the procedure in Step 5.
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