Ram 4500 Chassis Cab 2018 Owner's Manual

Tire Terminology And Definitions
TermDefinition
B-Pillar The vehicle B-Pillar is the structural member of the body located be-
hind the front door.
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 sitting for a minimum of three hours. In-
flation pressure is measured in units of PSI (pounds per square inch)
or kPa (kilopascals).
Maximum Inflation Pressure The maximum inflation pressure is the maximum permissible cold
tire inflation pressure for this tire. The maximum inflation pressure is
molded into the sidewall.
Recommended Cold Tire Inflation Pressure Vehicle manufacturer’s recommended cold tire inflation pressure as
shown on the tire placard.
Tire Placard A label permanently attached to the vehicle describing the vehicle’s
loading capacity, the original equipment tire sizes and the recom-
mended cold tire inflation pressures.
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Tire Loading And Tire Pressure
NOTE:The proper cold tire inflation pressure is listed on
the driver ’s side B-Pillar or the rear edge of the driver’s
side door.
Check the inflation pressure of each tire, including the
spare tire (if equipped), at least monthly and inflate to the
recommended pressure for your vehicle.
Example Tire Placard Location (Door)
Example Tire Placard Location (B-Pillar)
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Tire And Loading Information Placard
This placard tells you important information about the:
1. Number of people that can be carried in the vehicle.
2. Total weight your vehicle can carry.
3. Tire size designed for your vehicle.
4. Cold tire inflation pressures for the front, rear, and sparetires.Loading
The vehicle maximum load on the tire must not exceed the
load carrying capacity of the tire on your vehicle. You will
not exceed the tire’s load carrying capacity if you adhere to
the loading conditions, tire size, and cold tire inflation
pressures specified on the Tire and Loading Information
placard in “Vehicle Loading” in the “Starting And Operat-
ing” section of this manual.
NOTE: Under a maximum loaded vehicle condition, gross
axle weight ratings (GAWRs) for the front and rear axles
must not be exceeded.
For further information on GAWRs, vehicle loading, and
trailer towing, refer to “Vehicle Loading” in the “Starting
And Operating” section of this manual.
To determine the maximum loading conditions of your
vehicle, locate the statement “The combined weight of
occupants and cargo should never exceed XXX kg or
XXX lbs” on the Tire and Loading Information placard. The
combined weight of occupants, cargo/luggage and trailer
tongue weight (if applicable) should never exceed the
weight referenced here.
Tire And Loading Information Placard
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Steps For Determining Correct Load Limit—
(1) Locate the statement “The combined weight of
occupants and cargo should never exceed XXX kg or
XXX lbs.” on your vehicle’s placard.
(2) Determine the combined weight of the driver and
passengers that will be riding in your vehicle.
(3) Subtract the combined weight of the driver and
passengers from XXX kg or XXX lbs.
(4) The resulting figure equals the available amount of
cargo and luggage load capacity. For example, if “XXX”
amount equals 1400 lbs. and there will be five 150 lb
passengers in your vehicle, the amount of available
cargo and luggage load capacity is 650 lbs. (1400-750
(5x150) = 650 lbs.)
(5) Determine the combined weight of luggage and
cargo being loaded on the vehicle. That weight may not
safely exceed the available cargo and luggage load
capacity calculated in Step 4.
(6) If your vehicle will be towing a trailer, load from
your trailer will be transferred to your vehicle. Consult
this manual to determine how this reduces the available
cargo and luggage load capacity of your vehicle.Metric Example For Load Limit
For example, if “XXX” amount equals 635 kg and there will
be five 68 kg passengers in your vehicle, the amount of
available cargo and luggage load capacity is 295 kg (635-
340 (5x68) = 295 kg) as shown in step 4.
NOTE:
•If your vehicle will be towing a trailer, load from your
trailer will be transferred to your vehicle. The following
table shows examples on how to calculate total load,
cargo/luggage, and towing capacities of your vehicle
with varying seating configurations and number and
size of occupants. This table is for illustration purposes
only and may not be accurate for the seating and load
carry capacity of your vehicle.
• For the following example, the combined weight of
occupants and cargo should never exceed 865 lbs
(392 kg).
402 SERVICING AND MAINTENANCE

WARNING!
Overloading of your tires is dangerous. Overloading can
cause tire failure, affect vehicle handling, and increase
your stopping distance. Use tires of the recommended
load capacity for your vehicle. Never overload them.
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Tires — General Information
Tire Pressure
Proper tire inflation pressure is essential to the safe and
satisfactory operation of your vehicle. Four primary areas
are affected by improper tire pressure:
•Safety and Vehicle Stability
• Economy
• Tread Wear
• Ride Comfort
Safety
WARNING!
• Improperly inflated tires are dangerous and can
cause collisions.
• Underinflation increases tire flexing and can result
in overheating and tire failure.
• Overinflation reduces a tire’s ability to cushion
shock. Objects on the road and chuckholes can cause
damage that result in tire failure.
(Continued)
WARNING! (Continued)
•Overinflated or underinflated tires can affect vehicle
handling and can fail suddenly, resulting in loss of
vehicle control.
• Unequal tire pressures can cause steering problems.
You could lose control of your vehicle.
• Unequal tire pressures from one side of the vehicle
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.
Both under-inflation and over-inflation affect the stability
of the vehicle and can produce a feeling of sluggish
response or over responsiveness in the steering.
NOTE:
• Unequal tire pressures from side to side may cause
erratic and unpredictable steering response.
• Unequal tire pressure from side to side may cause the
vehicle to drift left or right.
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Fuel Economy
Underinflated tires will increase tire rolling resistance
resulting in higher fuel consumption.
Tread Wear
Improper cold tire inflation pressures can cause abnormal
wear patterns and reduced tread life, resulting in the need
for earlier tire replacement.
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.
At least once a month:
•Check and adjust tire pressure with a good quality
pocket-type pressure gauge. Do not make a visual
judgement when determining proper inflation. Tires
may look properly inflated even when they are under-
inflated.
• Inspect tires for signs of tire wear or visible damage.
CAUTION!
After inspecting or adjusting the tire pressure, always
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 sitting for a minimum of three hours. The
cold tire inflation pressure must not exceed the maximum
inflation 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 tem-
perature 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
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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 and
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 impor-
tant. Increased tire pressure and reduced vehicle loading
may be required for high-speed vehicle operation. Refer to
your authorized tire dealer or original equipment vehicle
dealer for recommended safe operating speeds, loading
and cold tire inflation pressures.
WARNING!
High speed driving with your vehicle under maximum
load is dangerous. The added strain on your tires could
cause them to fail. You could have a serious collision.
Do not 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 a collision. Always use
radial ply tires in sets of four. Never combine them
with other types of tires.
Tire Repair
If your tire becomes damaged, it may be repaired if it meets
the following criteria:
• The tire has not been driven on when flat.
• The damage is only on the tread section of your tire
(sidewall damage is not repairable).
• The puncture is no greater thana¼ofaninch (6 mm).
Consult an authorized tire dealer for tire repairs and
additional information.
Damaged Run Flat tires, or Run Flat tires that have
experienced a loss of pressure should be replaced immedi-
ately with another Run Flat tire of identical size and service
description (Load Index and Speed Symbol).
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Run Flat Tires — If Equipped
Run Flat tires allow you the capability to drive 50 miles
(80 km) at 50 mph (80 km/h) after a rapid loss of inflation
pressure. This rapid loss of inflation is referred to as the
Run Flat mode. A Run Flat mode occurs when the tire
inflation pressure is of/or below 14 psi (96 kPa). Once a
Run Flat tire reaches the run flat mode it has limited
driving capabilities and needs to be replaced immediately.
A Run Flat tire is not repairable.
It is not recommended driving a vehicle loaded at full
capacity or to tow a trailer while a tire is in the run flat
mode.
See the tire pressure monitoring section for more informa-
tion.
Tire Spinning
When stuck in mud, sand, snow, or ice conditions, do not
spin your vehicle’s wheels above 30 mph (48 km/h) or for
longer than 30 seconds continuously without stopping.
Refer to “Freeing A Stuck Vehicle” in “In Case Of Emer-
gency” for further information.
WARNING!
Fast spinning tires can be dangerous. Forces generated
by excessive wheel speeds may cause tire damage or
failure. A tire could explode and injure someone. Do
not spin your vehicle’s wheels faster than 30 mph
(48 km/h) for more than 30 seconds continuously when
you are stuck, and do not let anyone near a spinning
wheel, no matter what the speed.
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Tread Wear Indicators
Tread wear indicators are in the original equipment tires to
help you in determining when your tires should be re-
placed.
These indicators are molded into the bottom of the tread
grooves. They will appear as bands when the tread depth
becomes a 1/16 of an inch (1.6 mm). When the tread isworn to the tread wear indicators, the tire should be
replaced. Refer to “Replacement Tires” in this section for
further information.
Life Of Tire
The service life of a tire is dependent upon varying factors
including, but not limited to:
•
Driving style.
• Tire pressure - Improper cold tire inflation pressures can
cause uneven wear patterns to develop across the tire
tread. These abnormal wear patterns will reduce tread
life, resulting in the need for earlier tire replacement.
• Distance driven.
• Performance tires, tires with a speed rating of V or
higher, and Summer tires typically have a reduced tread
life. Rotation of these tires per the vehicle scheduled
maintenance is highly recommended.
WARNING!
Tires and the spare tire should be replaced after six
years, regardless of the remaining tread. Failure to
follow this warning can result in sudden tire failure.
(Continued)
Tire Tread
1—WornTire
2—NewTire 408 SERVICING AND MAINTENANCE