tire pressure Ram 3500 2019 Owner's Guide

532 SERVICING AND MAINTENANCE
NOTE:
• P (Passenger) — Metric tire sizing is based on U.S. designstandards. P-Metric tires have the letter “P” molded into
the sidewall preceding the size designation. Example:
P215/65R15 95H.
• European — Metric tire sizing is based on European design standards. Tires designed to this standard have the
tire size molded into the sidewall beginning with the
section width. The letter "P" is absent from this tire size
designation. Example: 215/65R15 96H. • LT (Light Truck) — Metric tire sizing is based on U.S.
design standards. The size designation for LT-Metric tires
is the same as for P-Metric tires except for the letters “LT”
that are molded into the sidewall preceding the size desig -
nation. Example: LT235/85R16.

• Temporary spare tires are designed for temporary emergency use only. Temporary high pressure compact spare tires have
the letter “T” or “S” molded into the sidewall preceding the
size designation. Example: T145/80D18 103M.

• High flotation tire sizing is based on U.S. design standards and it begins with the tire diameter molded into the side -
wall. Example: 31x10.5 R15 LT.

534 SERVICING AND MAINTENANCE
H = Speed Symbol
• A symbol indicating the range of speeds at which a tire can carry a load corresponding to its load index under certain oper -
ating conditions
• The maximum speed corresponding to the speed symbol should only be achieved under specified operating conditions (i.e., tire pressure, vehicle loading, road conditions, and posted speed limits)
Load Identification:
Absence of the following load identification symbols on the sidewall of the tire indicates a Standard Load (SL) tire:
• XL = Extra load (or reinforced) tire, or
• LL = Light load tire or
• C, D, E, F, G = Load range associated with the maximum load a tire can carry at a specified pressure
Maximum Load – Maximum load indicates the maximum load this tire is designed to carry
Maximum Pressure – Maximum pressure indicates the maximum permissible cold tire inflation pressure for this tire EXAMPLE:

536 SERVICING AND MAINTENANCE
Tire Terminology And DefinitionsTerm Definition
B-Pillar The vehicle B-Pillar is the structural member of the body located behind
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. Inflation 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 recommended
cold tire inflation pressures.

SERVICING AND MAINTENANCE 537
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 recom-
mended pressure for your vehicle.
Example Tire Placard Location (Door) Example Tire Placard Location (B-Pillar)
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538 SERVICING AND MAINTENANCE
Tire And Loading Information PlacardTire 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 spare tires. 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 pres
-
sures specified on the Tire and Loading Information placard
in “Vehicle Loading” in the “Starting And Operating”
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 occu-
pants 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 refer -
enced here.

SERVICING AND MAINTENANCE 541
(Continued)
Tires — General Information
Tire Pressure
Proper tire inflation pressure is essential to the safe and satis-
factory operation of your vehicle. Four primary areas are
affected by improper tire pressure:
• Safety and Vehicle Stability
• Economy
• Tread Wear
• Ride Comfort
Safety
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 erraticand unpredictable steering response.
• Unequal tire pressure from side to side may cause the vehicle to drift left or right.
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.
• Overinflated or underinflated tires can affect vehiclehandling 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.
WARNING! (Continued)
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542 SERVICING AND MAINTENANCE
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 qualitypocket-type pressure gauge. Do not make a visual judge -
ment 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.
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 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 tempera -
ture 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. 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.

SERVICING AND MAINTENANCE 543
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 and
within posted speed limits. Where speed limits or conditions
are such that the vehicle can be driven at high speeds, main-
taining correct tire inflation pressure is very important.
Increased tire pressure and reduced vehicle loading may be
required for high-speed vehicle operation. Refer to an autho -
rized tire dealer or original equipment vehicle dealer for
recommended safe operating speeds, loading and cold tire
inflation pressures. Radial Ply 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 (side
-
wall damage is not repairable).
• The puncture is no greater than a ¼ of an inch (6 mm).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).
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.
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544 SERVICING AND MAINTENANCE
Consult an authorized tire dealer for tire repairs and addi-
tional information.
Damaged Run Flat tires, or Run Flat tires that have experi -
enced a loss of pressure should be replaced immediately
with another Run Flat tire of identical size and service
description (Load Index and Speed Symbol). Replace the tire
pressure sensor as well as it is not designed to be reused.
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. When a run flat tire is changed after driving with
underinflated tire condition, please replace the TPM sensor
as it is not designed to be reused when driven under run flat
mode (14 psi (96 kPa)) condition. NOTE:
TPM Sensor must be replaced after driving the vehicle on a
flat tire condition.
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 information.

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.

SERVICING AND MAINTENANCE 545
Tread Wear Indicators
Tread wear indicators are in the original equipment tires to
help you in determining when your tires should be replaced.Tire Tread

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 is worn 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. Rota -
tion of these tires per the vehicle scheduled maintenance is
highly recommended.
1 — Worn Tire
2 — New Tire
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. You could
lose control and have a collision resulting in serious
injury or death.
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