tire pressure RAM CHASSIS CAB 2012 User Guide

WARNING! (Continued)• Unequal tire pressures from one side of the ve-
hicle to the other can cause the vehicle to drift to
the right or left.
• Always drive with each tire inflated to the recom-
mended cold tire inflation pressure.
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 resulting in higher fuel
consumption.
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 on the
driver’s side “B” Pillar or rear edge of the driver’s side
door.
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.
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.
5 STARTING AND OPERATING 319

CAUTION!After inspecting or adjusting the tire pressure, al-
ways reinstall the valve stem cap. 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 three hours, or driven less than
1 mile (1.6 km) after a three hour period. The cold tire
inflation pressure must not exceed the maximum infla-
tion pressure 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.
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.320 STARTING AND OPERATING

Tire Inflation Pressure – 4500/5500 With Steel
Carcass Ply Tires
This type of tire utilizes steel cords in the sidewall. As
such, they cannot be treated like normal light truck tires.
Adjusting tire pressure must be performed by personnel
trained, supervised and equipped accordingly. Inflation Pressure Adjustment When Mounted To
Vehicle
During procedures when adding tire inflation pressure,
the technician or individual must utilize a remote infla-
tion device, and ensure that all persons are clear of the
trajectory area.
5 STARTING AND OPERATING 321

When adjusting inflation pressure to a tire and wheel
assembly mounted on a vehicle, use a Remote Mount
Automatic Inflation Kit or see your authorized dealer.
NOTE: Never attempt to re-inflate a tire and wheel
assembly which has been run flat or is extremely under-
inflated without first removing the tire from the wheel
assembly for inspection.
Personnel trained, supervised, and equipped according
to Federal Occupational Safety and Health Administra-
tion (OSHA) should perform this work.
Inflation Pressure Adjustment When Not Mounted to
Vehicle
When adjusting inflation pressure to a tire and wheel
assembly not mounted on a vehicle, use a Remote Mount
Automatic Inflation Kit and a Tire Inflation Cage or see
your authorized dealer. 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 collision resulting in serious injury or death.
Don’t drive a vehicle loaded to the maximum capac-
ity at continuous speeds above 75 mph (120 km/h).
5 STARTING AND OPERATING 323

Full Size Spare – If Equipped
The full size spare is for temporary emergency use only.
This tire may look like the original equipped tire on the
front or rear axle of your vehicle, but it is not. This spare
tire may have limited tread life. When the tread is worn
to the tread wear indicators, the temporary use full size
spare tire needs to be replaced. Since it is not the same as
your original equipment tire, replace (or repair) the
original equipment tire and reinstall on the vehicle at the
first opportunity.
Limited-Use Spare – If Equipped
The limited-use spare tire is for temporary emergency
use only. This tire is identified by a label located on the
limited-use spare wheel. This label contains the driving
limitations for this spare. 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 as your original equipment tire, replace (or repair) the
original equipment tire and reinstall on the vehicle at the
first opportunity.
WARNING!Limited-use spares are for emergency use only. In-
stallation of this limited-use spare tire affects vehicle
handling. With this tire, do not drive more than the
speed listed on the limit-use spare wheel. Keep
inflated to the cold tire inflation pressure listed on
your Tire and Loading Information Placard located
on the driver ’s side door opening. Replace (or repair)
the original equipment tire at the first opportunity
and reinstall it on your vehicle. Failure to do so could
result in loss of vehicle control.326 STARTING AND OPERATING

These indicators are molded into the bottom of the tread
grooves. They will appear as bands when the tread depth
becomes 1/16 in (2 mm). When the tread is worn to the
tread wear indicators, the tire should be replaced.
Many states have laws requiring tire replacement at this
point.
Life Of Tire
The service life of a tire is dependent upon varying
factors including, but not limited to:
• Driving style
• Tire pressure
• Distance driven WARNING!Tires and spare tire should be replaced after six years,
regardless of the remaining tread. Failure to follow
this warning can result in sudden tire failure. You
could lose control and have a collision resulting in
serious injury or death.
Keep dismounted tires in a cool, dry place with as little
exposure to light as possible. Protect tires from contact
with oil, grease, and gasoline.
Replacement Tires
The tires on your new vehicle provide a balance of many
characteristics. They should be inspected regularly for
wear and correct cold tire inflation pressure. The manu-
facturer strongly recommends that you use tires equiva-
lent to the originals in size, quality and performance
when replacement is needed (refer to the paragraph on
“Tread Wear Indicators”). Refer to the “Tire and Loading328 STARTING AND OPERATING

WARNING! (Continued)• Never use a tire with a smaller load index or
capacity, other than what was originally equipped
on your vehicle. Using a tire with a smaller load
index could result in tire overloading and failure.
You could lose control and have a collision result-
ing in serious injury or death.
• Failure to equip your vehicle with tires having
adequate speed capability can result in sudden tire
failure and loss of vehicle control resulting in
serious injury or death.
CAUTION!Replacing original tires with tires of a different size
may result in false speedometer and odometer read-
ings. SUPPLEMENTAL TIRE PRESSURE INFORMATION
— IF EQUIPPED
A light load vehicle condition is defined as two passen-
gers [150 lbs (68 kg) each] plus 200 lbs (91 kg) of cargo.
Cold tire inflation pressures for a lightly loaded vehicle
will be found on the face of the driver’s door.
TIRE CHAINS
Use “Class U” chains or other traction aids that meet SAE
Type “U” specifications.
NOTE: Chains must be the proper size for the vehicle,
as recommended by the chain manufacturer.
CAUTION!To avoid damage to your vehicle, tires or chains,
observe the following precautions:
(Continued)330 STARTING AND OPERATING

• On 4X2 vehicles, class “U” snow chains are permitted
on the rear wheels only of vehicles equipped with
LT245/70R17, LT265/70R17, and LT235/80R17 size
tires.
• On 4X4 Single Rear Wheel (SRW) vehicles, class “U”
snow chains are permitted on the rear wheels only on
vehicles equipped with LT265/70R17.
CAUTION!Do not use tire chains on the 4X2 front wheels of
SRW (Single Rear Wheels) equipped with LT245/
70R17, LT265/70R17 tires or 4X4 front tires of vehicles
equipped with LT265/70R17 tires. There may not be
adequate clearance for the chains and you are risking
structural or body damage to your vehicle. SNOW TIRES
Some areas of the country require the use of snow tires
during the winter. All season tires can be identified by the
M+S designation on the tire sidewall.
If you need snow tires, select tires equivalent in size and
type to the original equipment tires. Use snow tires only
in sets of four; failure to do so may adversely affect the
safety and handling of your vehicle.
Snow tires generally have lower speed ratings than what
was originally equipped with your vehicle and should
not be operated at sustained speeds over 75 mph
(120 km/h). For speeds above 75 mph (120 km/h) refer to
original equipment or an authorized tire dealer for
recommended safe operating speeds, loading and cold
tire inflation pressures.332 STARTING AND OPERATING

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. Loading
The actual total weight and the weight of the front and
rear of your vehicle at the ground can best be determined
by weighing it when it is loaded and ready for operation.
The entire vehicle should first be weighed on a commer-
cial scale to insure that the GVWR has not been exceeded.
The weight on the front and rear of the vehicle should
then be determined separately to be sure that the load is
properly distributed over front and rear axle. Weighing
the vehicle may show that the GAWR of either the front
or rear axles has been exceeded but the total load is
within the specified GVWR. If so, weight must be shifted
from front to rear or rear to front as appropriate until the
specified weight limitations are met. Store the heavier
items down low and be sure that the weight is distributed
equally. Stow all loose items securely before driving.
5 STARTING AND OPERATING 343

WARNING! (Continued)• Safety chains must always be used between your
vehicle and trailer. Always connect the chains to
the hook retainers of the vehicle hitch. Cross the
chains under the trailer tongue and allow enough
slack for turning corners.
• Vehicles with trailers should not be parked on a
grade. When parking, apply the parking brake on
the tow vehicle. Put the tow vehicle transmission
in PARK. For four-wheel drive vehicles, make sure
the transfer case is not in NEUTRAL. Always,
block or  chock  the trailer wheels.
• GCWR must not be exceeded.
• Total weight must be distributed between the tow
vehicle and the trailer such that the following four
ratings are not exceeded:
1. GVWR
(Continued) WARNING! (Continued)2. GTW
3. GAWR
4. Trailer tongue weight rating for the trailer hitch
utilized (This requirement may limit the ability to
always achieve the 10% to 15% range of tongue
weight as a percentage of total trailer weight).
Towing Requirements – Tires
• Do not attempt to tow a trailer with less than the full
size spare tire.
• Proper tire inflation pressures are essential to the safe
and satisfactory operation of your vehicle. Refer to
“Tires – General Information” in “Starting and Oper-
ating” for proper tire inflation procedures.
• Check the trailer tires for proper tire inflation pres-
sures before trailer usage.352 STARTING AND OPERATING