tire size Ram 2500 2020 User Guide

STARTING AND OPERATING317
3. Stop filling the DEF tank immediately when
any of the following happen: DEF stops
flowing from the fill bottle into the DEF tank,
DEF splashes out the filler neck, or a DEF
pump nozzle automatically shuts off.
4. Reinstall cap onto DEF tank.
Filling The Def Tank In Cold Climates
Since DEF will begin to freeze at 12°F (-11°C),
your vehicle is equipped with an automatic DEF
heating system. This allows the DEF injection system to operate properly at temperatures
below 12°F (-11°C). If your vehicle is not in
operation for an extended period of time with
temperatures below 12°F (-11°C), the DEF in
the tank may freeze. If the tank is overfilled and
freezes, it could be damaged. Therefore, do not
overfill the DEF tank.
Extra care should be taken when filling with
portable containers to avoid overfilling. Note the
level of the DEF gauge in your instrument cluster.
You may safely add a maximum of 2 Gallons
(7.5 Liters) of DEF from portable containers
when your DEF gauge is reading ½ full.
VEHICLE LOADING
Gross Vehicle Weight Rating (GVWR)
The GVWR is the total permissible weight of your
vehicle including driver, passengers, vehicle,
options and cargo. The label also specifies
maximum capacities of front and rear axle
systems (GAWR). Total load must be limited so
GVWR and front and rear GAWR are not
exceeded.
Payload
The payload of a vehicle is defined as the allow
-
able load weight a truck can carry, including the
weight of the driver, all passengers, options and
cargo.
Gross Axle Weight Rating (GAWR)
The GAWR is the maximum permissible load on
the front and rear axles. The load must be
distributed in the cargo area so that the GAWR
of each axle is not exceeded.
Each axle GAWR is determined by the compo -
nents in the system with the lowest load
carrying capacity (axle, springs, tires or wheels).
Heavier axles or suspension components some -
times specified by purchasers for increased
durability does not necessarily increase the
vehicle's GVWR.
Tire Size
The tire size on the Vehicle Certification Label
represents the actual tire size on your vehicle.
Replacement tires must be equal to the load
capacity of this tire size.
Never add anything other than DEF to the
tank – especially any form of hydrocarbon
such as diesel fuel, fuel system additives,
gasoline, or any other petroleum-based
product. Even a very small amount of these,
less than 100 parts per million or less than
1 oz. per 78 Gallons (295 Liters) will
contaminate the entire DEF system and will
require replacement. If owners use a
container, funnel or nozzle when refilling
the tank, it should either be new or one that
is has only been used for adding DEF.
Mopar provides an attachable nozzle with
its DEF for this purpose.
CAUTION! (Continued)
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318STARTING AND OPERATING
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 condi -
tions, 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
commercial scale to ensure 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 the front and rear axles.
Weighing the vehicle may show that the GAWR
of either the front or rear axle has been
exceeded but the total load is within the speci
-
fied 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.
Improper weight distributions can have an
adverse effect on the way your vehicle steers
and handles and the way the brakes operate.
TRAILER TOWING
In this section you will find safety tips and infor -
mation on limits to the type of towing you can reasonably do with your vehicle. Before towing a
trailer, carefully review this information to tow
your load as efficiently and safely as possible.
To maintain the New Vehicle Limited Warranty
coverage, follow the requirements and recom
-
mendations in this manual concerning vehicles
used for trailer towing.
Common Towing Definitions
The following trailer towing-related definitions
will assist you in understanding the following
information:
Gross Vehicle Weight Rating (GVWR)
The GVWR is the total allowable weight of your
vehicle. This includes driver, passengers, cargo
and tongue weight. The total load must be
limited so that you do not exceed the GVWR.
Refer to “Vehicle Loading/Vehicle Certification
Label” in “Starting And Operating” for further
information.
Gross Trailer Weight (GTW)
The GTW is the weight of the trailer plus the
weight of all cargo, consumables and equip -
ment (permanent or temporary) loaded in or on
the trailer in its "loaded and ready for operation"
condition.
CAUTION!
Do not load your vehicle any heavier than the
GVWR or the maximum front and rear GAWR.
If you do, parts on your vehicle can break, or
it can change the way your vehicle handles.
This could cause you to lose control. Also
overloading can shorten the life of your
vehicle.

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STARTING AND OPERATING319
The recommended way to measure GTW is to
put your fully loaded trailer on a vehicle scale.
The entire weight of the trailer must be
supported by the scale.
Gross Combination Weight Rating (GCWR)
The GCWR is the total allowable weight of your
vehicle and trailer when weighed in combina -
tion.
Gross Axle Weight Rating (GAWR)
The GAWR is the maximum capacity of the front
and rear axles. Distribute the load over the front
and rear axles evenly. Make sure that you do
not exceed either front or rear GAWR. Refer to
“Vehicle Loading/Vehicle Certification Label” in
“Starting And Operating” for further informa -
tion.
Tongue Weight (TW)
The tongue weight is the downward force
exerted on the hitch ball by the trailer. You must
consider this as part of the load on your vehicle.
Trailer Frontal Area
The frontal area is the maximum height multi -
plied by the maximum width of the front of a
trailer.
Trailer Sway Control
The trailer sway control can be a mechanical
telescoping link that can be installed between
the hitch receiver and the trailer tongue that
typically provides adjustable friction associated
with the telescoping motion to dampen any
unwanted trailer swaying motions while trav -
eling. If equipped, the electronic Trailer Sway Control
(TSC) recognizes a swaying trailer and automat
-
ically applies individual wheel brakes and/or
reduces engine power to attempt to eliminate
the trailer sway.
Weight-Carrying Hitch
A weight-carrying hitch supports the trailer
tongue weight, just as if it were luggage located
at a hitch ball or some other connecting point of
the vehicle. These kinds of hitches are the most
popular on the market today and they are
commonly used to tow small and medium sized
trailers.
Weight-Distributing Hitch
A weight-distributing system works by applying
leverage through spring (load) bars. They are
typically used for heavier loads to distribute
trailer tongue weight to the tow vehicle's front
axle and the trailer axle(s). When used in accor -
dance with the manufacturer's directions, it
provides for a more level ride, offering more
consistent steering and brake control, thereby
enhancing towing safety. The addition of a fric -
tion/hydraulic sway control also dampens sway
caused by traffic and crosswinds and contrib -
utes positively to tow vehicle and trailer
stability. Trailer Sway Control (TSC) and a weight
WARNING!
If the gross trailer weight is 5,000 lbs (2,267 kg)
or more, it is recommended to use a
weight-distributing hitch to ensure stable
handling of your vehicle. If you use a standard
weight-carrying hitch, you could lose control of
your vehicle and cause a collision.
WARNING!
It is important that you do not exceed the
maximum front or rear GAWR. A dangerous
driving condition can result if either rating is
exceeded. You could lose control of the
vehicle and have a collision.
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324STARTING AND OPERATING
(Continued)
Towing Requirements — Tires
Do not attempt to tow a trailer while using a
compact spare tire.
Do not drive more than 50 mph (80 km/h) when towing while using a full size spare tire.
Proper tire inflation pressures are essential
to the safe and satisfactory operation of your
vehicle. Refer to “Tires” in “Servicing And
Maintenance” for proper tire inflation proce -
dures.
Check the trailer tires for proper tire inflation
pressures before trailer usage.
Check for signs of tire wear or visible tire
damage before towing a trailer. Refer to
“Tires” in “Servicing And Maintenance” for
the proper inspection procedure.
When replacing tires, refer to “Tires” in
“Servicing And Maintenance” for the proper
tire replacement procedures. Replacing tires
with a higher load carrying capacity will not
increase the vehicle's GVWR and GAWR
limits.
Towing Requirements — Trailer Brakes
Do not interconnect the hydraulic brake
system or vacuum system of your vehicle
with that of the trailer. This could cause inad -
equate braking and possible personal injury.
An electronically actuated trailer brake
controller is required when towing a trailer
with electronically actuated brakes. When
towing a trailer equipped with a hydraulic
surge actuated brake system, an electronic
brake controller is not required.
Trailer brakes are recommended for trailers
over 1,000 lbs (453 kg) and required for
trailers in excess of 2,000 lbs (907 kg).
When hauling cargo or towing a trailer, do
not overload your vehicle or trailer. Over -
loading can cause a loss of control, poor
performance or damage to brakes, axle,
engine, transmission, steering, suspension,
chassis structure or tires.
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.
WARNING! (Continued)
Total weight must be distributed between
the tow vehicle and the trailer such that the
following four ratings are not exceeded :
GVWR
GTW
GAWR
Tongue weight rating for the trailer
hitch utilized.
WARNING! (Continued)

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422SERVICING AND MAINTENANCE
HOISTING
A conventional floor jack may be used at the
jacking locations. However, a floor jack or frame
hoist must never be used on any other parts of
the underbody.
TIRES
Tire Safety Information
Tire safety information will cover aspects of the
following information: Tire Markings, Tire Identi -
fication Numbers, Tire Terminology and Defini -
tions, 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.
ODOMETER
READING
PERFORMED
BY
PERFORMED AT
Noise Systems Maintenance Chart and Service Log — Insert Month, Day, Year under column mileage closest to the mileage at which
service was performed.
CAUTION!
Never use a floor jack directly under the
differential housing of a loaded truck or
damage to your vehicle may result.
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 MAINTENANCE423
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 standards and it begins with the tire
diameter molded into the sidewall. Example:
31x10.5 R15 LT.
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)
7

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SERVICING AND MAINTENANCE425
Tire Terminology And Definitions
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
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.
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426SERVICING 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 pres -
sure 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.
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.
Term
Definition

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SERVICING AND MAINTENANCE427
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 Infor -
mation 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 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 avail
-
able 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 avail
-
able 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
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430SERVICING AND MAINTENANCE
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 a 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 pres -
sure 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 condi
-
tions, 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
Emergency” for further information.
Tread Wear Indicators
Tread wear indicators are in the original equip -
ment tires to help you in determining when your
tires should be replaced.

Tire Tread

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.
1 — Worn Tire
2 — New Tire

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