tire size RAM 1500 2023 User Guide

SAFETY273
Automatic Trailer Detection
There are two modes of operation for the detection of the
trailer length:
Automatic Mode — When “Auto Mode” is selected, the
system will use the blind spot sensors to automatically
determine the presence and length of a trailer. The
presence of a trailer will be detected using the blind
spot radar within 90 seconds of forward movement of
the vehicle. The vehicle must be moving above 6 mph
(10 km/h) to activate the feature. Once the trailer has
been detected, the system will default to the maximum
blind spot zone until the length has been verified. You
will see “Auto” in the instrument panel cluster .
 Maximum Mode — When “Max Mode” is selected, the
system will default to the maximum blind spot zone
regardless of what size trailer is attached .
NOTE:Selected setting is stored when the ignition is placed in the
OFF position. To change this setting, it must be selected
through the Uconnect Settings
Úpage 191.
Trailer Length Detection
Once the trailer presence has been established, the trailer
length will be established (by making a 90 degree turn)
and then the trailer length category (example 10-20 ft
(3 m to 6 m)) will be displayed. This can take up to
30 seconds after completing the turn.
NOTE:During the same ignition cycle, if the vehicle is at a
standstill for a minimum of 90 seconds, a new “trailer
detection request” is enabled by the system once the
vehicle resumes motion.
The maximum trailer length supported by the Trailer
Merge Assist feature is 39.5 ft (12 m). Trailer length is
considered the forward most portion of the trailer hitch to
the rearward most portion of the body, fascia/bumper, or
ramp of the trailer.
The maximum width supported by the Trailer Merge Assist
feature is 8.5 ft (2.59 m). Trailer width is measured at the
widest portion of the trailer and may include wheels, tires,
finders, or rails.
NOTE:Fifth wheel or gooseneck trailers are not supported by
Trailer Merge Assist.
NOTE:The ability to detect a trailer may be degraded in crowded
or busy environments. Busy parking lots, narrow areas
surrounded with trees, or any other crowded area may
prevent the radar sensors from being able to adequately
detect the trailer. The system will try to detect a trailer at
every ignition cycle or 90 seconds of standstill.

Trailer Length Detection

Trailer length will be identified and placed into one of the
following categories:
 Trailer length up to 10 ft (3 m) — Blind spot zone will be
adjusted to 10 ft (3 m) .
 Trailer length between 10 ft to 20 ft
(3 m to 6 m) — Blind spot zone will be adjusted to
20 ft (6 m) .
 Trailer length between 20 ft to 30 ft
(6 m to 9 m) — Blind spot zone will be adjusted to
30 ft (9 m) .
 Trailer length between 30 ft and 39.5 ft
(9 m to 12 m) — Blind spot zone will be adjusted to
Max distance .
1 — Trailer Length
2 — Trailer Hitch
3 — Trailer Width
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SAFETY277
TIRE PRESSURE MONITORING SYSTEM
(TPMS)
TPMS will warn the driver of a low tire pressure based on
the vehicle recommended cold placard pressure.
NOTE:The TPMS Warning Light will illuminate in the instrument
cluster and a chime will sound when tire pressure is low in
one or more of the four active road tires. In addition, the
instrument cluster will display a graphic showing the
pressure values of each tire with the low tire pressure
values in a different color, or the Uconnect radio will
display a TPMS message; when this occurs you must
increase the tire pressure to the recommended cold
placard pressure in order for the TPMS Warning Light to
turn off.
The tire pressure will vary with temperature by about 1 psi
(7 kPa) for every 12°F (6.5°C). This means that when the
outside temperature decreases, the tire pressure will
decrease. Tire pressure should always be set based on
cold inflation tire pressure. This 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 inflation pressure molded into the
tire sidewall. The tire pressure will also increase as the
vehicle is driven — this is normal and there should be no
adjustment for this increased pressure.
See
Úpage 370 on how to properly inflate the vehicle’s
tires. The TPMS will warn the driver of a low tire pressure if the
tire pressure falls below the low-pressure warning limit for
any reason, including low temperature effects and natural
pressure loss through the tire
Úpage 402.
The TPMS will continue to warn the driver of low tire
pressure as long as the condition exists, and will not turn
off until the tire pressure is at or above the recommended
cold placard pressure. Once the low TPMS Warning Light
illuminates, increase the tire pressure to the
recommended cold placard pressure in order for the
TPMS Warning Light to turn off. The system will
automatically update and the TPMS Warning Light will turn
off once the system receives the updated tire pressures.
The vehicle may need to be driven for up to 20 minutes
above 15 mph (24 km/h) in order for the TPMS to receive
this information.
NOTE:When filling warm tires, the tire pressure may need to be
increased up to an additional 4 psi (28 kPa) above the
recommended cold placard pressure in order to turn the
TPMS Warning Light off.
For example, your vehicle may have a recommended cold
(parked for more than three hours) placard pressure of
30 psi (207 kPa). If the ambient temperature is 68°F
(20°C) and the measured tire pressure is 27 psi
(186 kPa), a temperature drop to 20°F (-7°C) will
decrease the tire pressure to approximately 23 psi
(158 kPa). This tire pressure is sufficiently low enough
to turn on the TPMS Warning Light. Driving the vehicle may cause the tire pressure to rise to
approximately 27 psi (186 kPa), but the TPMS Warning
Light will still be on. In this situation, the TPMS Warning
Light will turn off only after the tires are inflated to the
vehicle’s recommended cold placard pressure value.
CAUTION!

The TPMS has been optimized for the original equip -
ment tires and wheels. TPMS pressures and warning
have been established for the tire size equipped on
your vehicle. Undesirable system operation or sensor
damage may result when using replacement equip -
ment that is not of the same size, type, and/or style.
Aftermarket wheels can cause sensor damage.
 Using aftermarket tire sealants may cause the Tire
Pressure Monitoring System (TPMS) sensor to
become inoperable. After using an aftermarket tire
sealant it is recommended that you take your vehicle
to an authorized dealership to have your sensor func -
tion checked.
 After inspecting or adjusting the tire pressure always
reinstall the valve stem cap. This will prevent mois -
ture and dirt from entering the valve stem, which
could damage the TPMS sensor.
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SAFETY279
Service TPMS Warning
If a system fault is detected, the Tire Pressure Monitoring
System (TPMS) Warning Light will flash on and off for 75
seconds and then remain on solid. The system fault will
also sound a chime. In addition, the instrument cluster will
display a "SERVICE TPM SYSTEM" message for a minimum
of five seconds and then display dashes (--) in place of the
pressure value to indicate which sensor is not being
received.
If the ignition switch is cycled, this sequence will repeat,
providing the system fault still exists. If the system fault no
longer exists, the Tire Pressure Monitoring System
Warning Light will no longer flash, and the "SERVICE TPM
SYSTEM" message will no longer display, and a pressure
value will display in place of the dashes. A system fault can
occur due to any of the following:
Signal interference due to electronic devices or driving
next to facilities emitting the same radio frequencies
as the Tire Pressure Monitoring System sensors
 Installing aftermarket window tinting that contains
materials that may block radio wave signals
 Accumulation of snow or ice around the wheels or
wheel housings
 Using tire chains on the vehicle
 Using wheels/tires not equipped with TPMS sensors
A system fault may occur due to an incorrect TPMS sensor
location condition. When a system fault occurs due to an
incorrect TPMS sensor location, the Tire Pressure
Monitoring System (TPMS) Warning Light will flash on and
off for 75 seconds and then remain on solid. The system fault will also sound a chime. In addition, the
instrument cluster will display a Tire Pressure Temporarily
Unavailable message in place of the tire pressure display
screen. If the ignition switch is cycled, this sequence will
repeat, providing the system fault still exists. If the system
fault no longer exists, the “Tire Pressure Monitoring
System Warning Light” will no longer flash and the tire
pressure display screen will be displayed showing the tire
pressure values the correct locations.
Vehicles With Non-Matching Full Size Spare Or Compact
Spare

The non-matching full size spare or compact spare tire
does not have a TPMS sensor. Therefore, the TPMS will
not monitor the pressure in the non-matching full size
spare or compact spare tire.
 If you install the non-matching full size spare or
compact spare tire in place of a road tire that has a
pressure below the low-pressure warning limit, upon
the next ignition switch cycle, the Tire Pressure
Monitoring System (TPMS) Warning Light and a
“LOW TIRE” message will remain on and a chime will
sound. In addition, the graphic in the instrument
cluster will still display a pressure value in a different
color and an “Inflate to XX” message.
 After driving the vehicle for up to 20 minutes above
15 mph (24 km/h), the Tire Pressure Monitoring
System (TPMS) Warning Light will flash on and off for
75 seconds and then remain on solid. In addition, the
instrument cluster will display a "SERVICE TPM
SYSTEM" message for a minimum of five seconds and
then display dashes (--) in place of the pressure value. 
For each subsequent ignition switch cycle, a chime will
sound, the Tire Pressure Monitoring System (TPMS)
Warning Light will flash on and off for 75 seconds and
then remain on solid, and the instrument cluster will
display a "SERVICE TPM SYSTEM" message for a
minimum of five seconds and then display dashes (--)
in place of the pressure value.
 Once you repair or replace the original road tire and
reinstall it on the vehicle in place of the non-matching
full size spare or compact spare, the TPMS will update
automatically. In addition, the Tire Pressure Monitoring
System (TPMS) Warning Light will turn off and the
graphic in the instrument cluster will display a new
pressure value instead of dashes (--), as long as no tire
pressure is below the low-pressure warning limit in any
of the four active road tires. The vehicle may need to be
driven for up to 20 minutes above 15 mph (24 km/h)
in order for the TPMS to receive this information.
Tire Fill Alert
This feature notifies the user when the placard tire
pressure is attained while inflating or deflating the tire.
You may choose to disable or enable the Tire Fill Alert
feature through use of the Uconnect Settings in the radio.
NOTE:
Only one tire can be filled at a time when using the Tire
Fill Alert system.
 The Tire Fill Alert feature cannot be entered if an
existing TPMS fault is set to “active” or if the system is
in deactivation mode (if equipped).
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370SERVICING AND MAINTENANCE
TIRES
TIRE SAFETY INFORMATION
Tire safety information will cover aspects of the following
information: Tire Markings, Tire Identification Numbers,
Tire Terminology and Definitions, Tire Pressures, and Tire
Loading.
Tire Markings

Tire Markings

NOTE:
P (Passenger) — Metric tire sizing is based on US design
standards. 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 US
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 designation.
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 US design stan -
dards and it begins with the tire diameter molded into
the sidewall.
Example: 31x10.5 R15 LT.
1 — US DOT Safety Standards Code
(TIN)
2 — Size Designation
3 — Service Description
4 — Maximum Load
5 — Maximum Pressure
6 — Treadwear, Traction and
Temperature Grades

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SERVICING AND MAINTENANCE371
TIRE SIZING CHART
EXAMPLE:
Example Size Designation: P215/65R15XL 95H, 215/65R15 96H, LT235/85R16C, T145/80D18 103M, 31x10.5 R15 LT
P = Passenger car tire size based on US design standards, or
"....blank...." = Passenger car tire based on European design standards, or
LT = Light truck tire based on US design standards, or
T or S = Temporary spare tire or
31 = Overall diameter in inches (in)
215, 235, 145 = Section width in millimeters (mm)
65, 85, 80 = Aspect ratio in percent (%)
 Ratio of section height to section width of tire, or
10.5 = Section width in inches (in)
R = Construction code
 "R" means radial construction, or
 "D" means diagonal or bias construction
15, 16, 18 = Rim diameter in inches (in)
Service Description:
95 = Load Index
 A numerical code associated with the maximum load a tire can carry
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 operating 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)
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372SERVICING AND MAINTENANCE
Tire Identification Number (TIN)
The Tire Identification Number (TIN) may be found on one or both sides of the tire; however, the date code may only be on one side. Tires with white sidewalls will have the full TIN,
including the date code, located on the white sidewall side of the tire. Look for the TIN on the outboard side of black sidewall tires as mounted on the vehicle. If the TIN is not found on
the outboard side, then you will find it on the inboard side of the tire.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:
EXAMPLE:
DOT MA L9 ABCD 0301
DOT = Department of Transportation
 This symbol certifies that the tire is in compliance with the US Department of Transportation tire safety standards and is approved for highway use
MA = Code representing the tire manufacturing location (two digits)
L9 = Code representing the tire size (two digits)
ABCD = Code used by the tire manufacturer (one to four digits)

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SERVICING AND MAINTENANCE373
Tire Terminology And Definitions
03 = Number representing the week in which the tire was manufactured (two digits)
 03 means the 3rd week
01 = Number representing the year in which the tire was manufactured (two digits)
 01 means the year 2001
 Prior to July 2000, tire manufacturers were only required to have one number to represent the year in which the tire was manufactured. Example: 031 could represent the 3rd
week of 1981 or 1991
Term Definition
B-pillarThe 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 The 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.
EXAMPLE:
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374SERVICING AND MAINTENANCE
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)

Tire And Loading Information Placard

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
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
pressures specified on the Tire And Loading Information
Placard in Vehicle Loading
Úpage 172.
NOTE:Under a maximum loaded vehicle condition, Gross Axle
Weight Rating (GAWR) for the front and rear axles must
not be exceeded.
For further information on GAWR, vehicle loading, and
trailer towing
Úpage 172.
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.

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378SERVICING AND MAINTENANCE
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.
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, maintaining 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 authorized 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
(sidewall damage is not repairable)
 The puncture is no greater than ¼ of an inch (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
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 being driven in a Run Flat mode
14 psi (96 kPa) condition, please replace the TPMS sensor
as it is not designed to be reused.
NOTE:The TPMS 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.
For more information
Úpage 277.
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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380SERVICING AND MAINTENANCE
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 pressures. The
manufacturer strongly recommends using tires equivalent
to the originals in size, quality and performance when
replacement is needed
Úpage 379. Refer to the Tire And
Loading Information Placard or the Vehicle Certification
Label for the size designation of your tire. The Load Index
and Speed Symbol for your tire will be found on the original
equipment tire sidewall.
For more information relating to the Load Index and Speed
Symbol of a tire
Úpage 371.
It is recommended to replace the two front tires or two rear
tires as a pair. Replacing just one tire can seriously affect
your vehicle’s handling. If you ever replace a wheel, make
sure that the wheel’s specifications match those of the
original wheels.
It is recommended you contact an authorized tire dealer or
original equipment dealer with any questions you may
have on tire specifications or capability. Failure to use
equivalent replacement tires may adversely affect the
safety, handling, and ride of your vehicle.
TIRE TYPES
All Season Tires — If Equipped
All Season tires provide traction for all seasons (Spring,
Summer, Autumn, and Winter). Traction levels may vary
between different all season tires. All season tires can be
identified by the M+S, M&S, M/S or MS designation on the
tire sidewall. Use all season tires only in sets of four;
failure to do so may adversely affect the safety and
handling of your vehicle.
Summer Or Three Season Tires —
If Equipped
Summer tires provide traction in both wet and dry
conditions, and are not intended to be driven in snow or on
ice. If your vehicle is equipped with Summer tires, be
aware these tires are not designed for Winter or cold
driving conditions. Install Winter tires on your vehicle when
ambient temperatures are less than 40°F (5°C) or if
roads are covered with ice or snow. For more information,
contact an authorized dealer.
Summer tires do not contain the all season designation or
mountain/snowflake symbol on the tire sidewall. Use
Summer tires only in sets of four; failure to do so may
adversely affect the safety and handling of your vehicle.
WARNING!
 Do not use a tire, wheel size, load rating, or speed
rating other than that specified for your vehicle.
Some combinations of unapproved tires and wheels
may change suspension dimensions and perfor -
mance characteristics, resulting in changes to
steering, handling, and braking of your vehicle. This
can cause unpredictable handling and stress to
steering and suspension components. You could
lose control and have a collision resulting in serious
injury or death. Use only the tire and wheel sizes with
load ratings approved for your vehicle.
 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.
 Failure to equip your vehicle with tires having
adequate speed capability can result in sudden tire
failure and loss of vehicle control.
CAUTION!
Replacing original tires with tires of a different size may
result in false speedometer and odometer readings.WARNING!
Do not use Summer tires in snow/ice conditions. You
could lose vehicle control, resulting in severe injury or
death. Driving too fast for conditions also creates the
possibility of loss of vehicle control.

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