2. Economy—
Improper inflation pressures can cause uneven wear
patterns to develop across the tire tread. These abnormal
wear patterns will reduce tread life resulting in a need for
earlier tire replacement. Under inflation, also increases
tire rolling resistance and results in higher fuel consump-
tion.
3. Ride Comfort and Vehicle Stability—
Proper tire inflation contributes to a comfortable ride.
Over inflation produces a jarring and uncomfortable ride.
Tire Inflation Pressures
The proper cold tire inflation pressure is listed either on
the face of the driver’s door or on the driver’s side “B”
pillar. Some vehicles may have Supplemental Tire Pressure
Information for vehicle loads that are less than the
maximum loaded vehicle condition. These pressure con-
ditions will be found in the “Supplemental Tire Pressure
Information” section of this manual.
Tire Placard Location STARTING AND OPERATING 337
5
The pressure should be checked and adjusted as well as
inspecting for signs of tire wear or visible damage at least
once a month. Use a good quality pocket-type gauge to
check tire pressure. Do not make a visual judgement
when determining proper inflation. Radial tires may look
properly inflated even when they are under inflated.
CAUTION!After inspecting or adjusting the tire pressure, al-
ways reinstall the valve stem cap (if equipped). This
will prevent moisture and dirt from entering the
valve stem, which could damage the valve stem. Inflation pressures specified on the placard are always
“cold tire inflation pressure.” Cold tire inflation pressure
is defined as the tire pressure after the vehicle has not
been driven for at least 3 hours, or driven less than 1 mile
(1 km) after a 3 hour period. The cold tire inflation
pressure must not exceed the maximum inflation pres-
sure molded into the tire sidewall.
Check tire pressures more often if subject to a wide range
of outdoor temperatures, as tire pressures vary with
temperature changes.
Tire pressures change by approximately 1 psi (7 kPa) per
12 °F (7 °C) of air temperature change. Keep this in mind
when checking tire pressure inside a garage, especially in
the winter.338 STARTING AND OPERATING
Example: If garage temperature = 68 °F (20 °C) and the
outside temperature = 32 °F (0 °C) then the cold tire
inflation pressure should be increased by 3 psi (21 kPa),
which equals 1 psi (7 kPa) for every 12 °F (7 °C) for this
outside temperature condition.
Tire pressure may increase from 2 to 6 psi (13 to 40 kPa)
during operation. DO NOT reduce this normal pressure
build up or your tire pressure will be too low.
Tire Pressures for High Speed Operation
The manufacturer advocates driving at safe speeds
within posted speed limits. Where speed limits or condi-
tions are such that the vehicle can be driven at high
speeds, maintaining correct tire inflation pressure is very
important. Increased tire pressure and reduced vehicle
loading may be required for high-speed vehicle opera-
tion. Refer to original equipment or an authorized tire
dealer for recommended safe operating speeds, loading
and cold tire inflation pressures. WARNING!High speed driving with your vehicle under maxi-
mum load is dangerous. The added strain on your
tires could cause them to fail. You could have a
serious accident. Don’t drive a vehicle loaded to the
maximum capacity at continuous speeds above 75
mph (120 km/h).
Radial-Ply Tires
WARNING!Combining radial ply tires with other types of tires
on your vehicle will cause your vehicle to handle
poorly. The instability could cause an accident. Al-
ways use radial ply tires in sets of four (or 6, in case
of trucks with dual rear wheels). Never combine
them with other types of tires. STARTING AND OPERATING 339
5
CAUTION!Because of the reduced ground clearance, do not take
your vehicle through an automatic car wash with the
compact spare installed. Damage to the vehicle may
result.
Limited Use Spare — If Equipped
The limited use spare tire is for temporary emergency use
on your vehicle. This tire is identified by a limited use
spare tire warning label located on the limited use spare
tire and wheel assembly. This tire may look like the
original equipped tire on the front or rear axle of your
vehicle, but it is not. Installation of this limited use spare
tire affects vehicle handling. Since it is not the same tire,
replace (or repair) the original tire and reinstall on the
vehicle at the first opportunity. WARNING!The limited use spare tires are for emergency use
only. Installation of this limited use spare tire affects
vehicle handling. With this tire, do not drive more
than 60 mph (100 km/h). Keep inflated to the cold
tire inflation pressure listed on either your tire
placard or limited use spare tire and wheel assembly.
Replace (or repair) the original tire at the first
opportunity and reinstall it on your vehicle. Failure
to do so could result in loss of vehicle control.
Tire Spinning
When stuck in mud, sand, snow, or ice conditions, do not
spin your vehicle’s wheels above 30 mph (48 km/h).
Refer to the paragraph on “Freeing A Stuck Vehicle” in
Section 6 of this manual. STARTING AND OPERATING 341
5
Tire Pressure Monitoring Low Pressure Warnings
The Tire Pressure Monitoring Telltale Lamp will
illuminate in the instrument cluster and an audible
chime will be activated when one or more of the
four active road tire pressures are low. The audible chime
will sound once every ignition cycle for each low tire
condition that it detects.
Should this occur you should stop as soon as possible,
check the inflation pressure of each tire on your vehicle,
and inflate each tire to the pressure recommended by the
vehicle tire pressure placard. The system will automati-
cally update and the Tire Pressure Monitor System Tell-
tale Lamp will extinguish once the updated tire pres-
sure(s) have been received.
NOTE: The vehicle may need to be driven for up to 10
minutes above 15 mph (25 km/h) to receive this infor-
mation. NOTE: A low spare or compact tire pressure will not
cause the Tire Pressure Monitor System Telltale Lamp to
illuminate or the chime to sound.
Base Tire Pressure Monitoring System with
Electronic Vehicle Information Center (EVIC) — If
Equipped
The Tire Pressure Monitor System (TPMS) uses wireless
technology with wheel rim mounted electronic sensors to
monitor tire pressure levels (EXCLUDING THE SPARE
TIRE). Sensors, mounted to each wheel as part of the
valve stem, transmit tire pressure readings to the Re-
ceiver Module.
NOTE: It is particularly important, for you to check the
tire pressure in all of your tires regularly and too main-
tain the proper pressure.
The Tire Pressure Monitor System (TPMS) consists of the
following components: STARTING AND OPERATING 349
5
Tire Size
The tire size on the Label represents the actual tire size on
your vehicle. Replacement tires must be equal to the load
capacity of this tire size.
Rim Size
This is the rim size that is appropriate for the tire size
listed.
Inflation Pressure
This is the cold tire inflation pressure for your vehicle for
all loading conditions up to full GAWR.
Curb Weight
The curb weight of a vehicle is defined as the total weight
of the vehicle with all fluids, including vehicle fuel, at full
capacity conditions, and with no occupants or cargo
loaded into the vehicle. The front and rear curb weight
values are determined by weighing your vehicle on a
commercial scale before any occupants or cargo are
added. Overloading
The load carrying components (axle, springs, tires,
wheels, etc.) of your vehicle will provide satisfactory
service as long as you do not exceed the GVWR and front
and rear GAWR.
The best way to figure out the total weight of your
vehicle is to weigh it when it is fully loaded and ready for
operation. Weigh it on a commercial scale to insure that it
is not over the GVWR.
Figure out the weight on the front and rear of the vehicle
separately. It is important that you distribute the load
evenly over the front and rear axles.
Overloading can cause potential safety hazards and
shorten useful service life. Heavier axles or suspension
components do not necessarily increase the vehicle’s
GVWR. STARTING AND OPERATING 365
5