tire size RAM 1500 2022 User Guide

324SAFETY
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 pres -
ence 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
Ú page 234. 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

1 — Trailer Length
2 — Trailer Hitch
3 — Trailer Width

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SAFETY329
(Continued)
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 Ú
page 480.
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.
NOTE:
The TPMS is not intended to replace normal tire
care and maintenance or to provide warning of
a tire failure or condition.
The TPMS should not be used as a tire pressure
gauge while adjusting your tire pressure, unless
your vehicle is equipped with a Tire Fill Alert
(TFA) system.
Driving on a significantly underinflated tire
causes the tire to overheat and can lead to tire
failure. Underinflation also reduces fuel effi
-
ciency and tire tread life, and may affect the
vehicle’s handling and stopping ability.
CAUTION!
The TPMS has been optimized for the original
equipment 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 equipment
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 function
checked.
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 TPMS
sensor.
CAUTION!
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SAFETY331
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 Tire Pressure Monitoring System
Warning Light off.
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. There
-
fore, 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 pres -
sure 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.
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332SAFETY
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).
The system will be activated when a positive
increase in tire pressure is detected by the TPMS
while inflating the tire. The ignition must be in the
RUN mode, with the transmission in PARK.
NOTE:It is not required to have the engine running to
enter Tire Fill Alert mode.
The hazard lamps will come on to confirm the
vehicle is in Tire Fill Alert mode.
When Tire Fill Alert mode is entered, the tire
pressure display screen will be displayed in the
instrument cluster.
If the hazard lamps do not come on while inflating
the tire, the TPMS sensor may be out of range
preventing the TPMS sensor signal from being
received. In this case, the vehicle may need to be
moved either forward or backward slightly to exit
the null spot. Operation:
The horn will sound once to let the user know
when to stop filling the tire, when it reaches
recommended pressure.
The horn will sound three times if the tire is over
-
filled and will continue to sound every five
seconds if the user continues to inflate the tire.
The horn will sound once again when enough air
is let out to reach proper inflation level.
The horn will also sound three times if the tire is
then underinflated and will continue to sound
every five seconds if the user continues to
deflate the tire.
Trailer Tire Pressure Monitoring System
(TTPMS) — If Equipped
The Trailer Tire Pressure Monitoring System
(TTPMS) is a feature that displays the trailer tire
pressure values and warns the driver of a low tire
pressure event based on the driver’s set target tire
pressure value, through TTPMS settings found in
the radio.
The TTPMS monitors the pressure of each tire and
warns the driver through the instrument cluster,
when either a low tire pressure condition falls
below 25% of the driver’s set pressure or if a
system malfunction occurs. The instrument cluster
will display the actual tire pressure or dashes for
each of the trailer tires in the correct trailer
position, based on trailer configuration.

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444SERVICING 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 Euro -
pean design standards. Tires designed to this
standard have the tire size molded into the side -
wall 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 tempo -
rary emergency use only. Temporary high pres -
sure 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
standards 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 Tempera -
ture Grades

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SERVICING AND MAINTENANCE445
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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446SERVICING 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)
03 = Number representing the week in which the tire was manufactured (two digits)
03 means the 3rd week

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SERVICING AND MAINTENANCE447
Tire Terminology And Definitions
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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448SERVICING 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 Ú page 211.
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 Ú page 211.

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SERVICING AND MAINTENANCE449
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.
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 occu
-
pants. 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).
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