2020 Ram 3500 Chassis Cab tire size

226STARTING AND OPERATING
Manually Shifted Transfer Case — If
Equipped
The transfer case provides four mode positions:
Two-Wheel Drive High Range (2H)
Four-Wheel Drive Lock High Range (4H)
N (Neutral)
Four-Wheel Drive Low Range (4L)
For additional information on the appropriate
use of each transfer case mode position, see
the information below:
2H
Two-Wheel Drive High Range — This range is for
normal street and highway driving on dry, hard
surfaced roads.
4H
Four-Wheel Drive Lock High Range — This range
locks the front and rear driveshafts together
forcing the front and rear wheels to rotate at the
same speed. Additional traction for loose, slip -
pery road surfaces only. N (Neutral)
N (Neutral) — This range disengages both the
front and rear driveshafts from the powertrain.
To be used for flat towing behind another
vehicle. Refer to “Recreational Towing” in
“Starting And Operating” for further informa
-
tion.
4L
Four-Wheel Drive Low Range — This range locks
the front and rear driveshafts together forcing
the front and rear wheels to rotate at the same
speed. Additional traction and maximum pulling
power for loose, slippery road surfaces only. Do
not exceed 25 mph (40 km/h).
This transfer case is intended to be driven in the
2H position for normal street and highway
conditions such as dry, hard surfaced roads.
When additional traction is required, the 4H and
4L positions can be used to lock the front and
rear driveshafts together and force the front
and rear wheels to rotate at the same speed.
This is accomplished by simply moving the gear
selector to the desired positions once the
appropriate speed and gear requirements are
met, refer to “Shifting Procedure – Manually
Shifted Transfer Case” in this section for further
information. The 4H and 4L positions are intended for loose,
slippery road surfaces only. Driving in the 4H
and 4L positions on dry, hard surfaced roads
may cause increased tire wear and damage to
the driveline components.
The “Transfer Case Position Indicator Light” in
the instrument cluster will alert the driver that
the vehicle is in four-wheel drive and that the
front and rear driveshafts are locked together.
This light will illuminate when the transfer case
is shifted into either the 4H or 4L position. There
is no light for the 2H or Neutral positions on
some models.
When operating your vehicle in 4L, the engine
speed is approximately three times that of the
2H or 4H positions at a given road speed. Take
care not to overspeed the engine and do not
exceed 25 mph (40 km/h).
Proper operation of four-wheel drive vehicles
depends on tires of equal size, type and circum
-
ference on each wheel. Any difference will
adversely affect shifting and can cause damage
to the drivetrain.
NOTE:
Do not attempt to make a shift while only the
front or rear wheels are spinning, as this can
cause damage to driveline components.

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STARTING AND OPERATING233
(Continued)
Adaptive Cruise Control (ACC) Operation
The speed control buttons (located on the right
side of the steering wheel) operate the ACC
system.
Adaptive Cruise Control Buttons

NOTE:
Any chassis/suspension or tire size modifica -
tions to the vehicle will affect the performance
of the Adaptive Cruise Control and Forward
Collision Warning System.
Does not always fully recognize complex driving conditions, which can
result in wrong or missing distance
warnings.
Will bring the vehicle to a complete stop while following a target vehicle and hold
the vehicle for approximately two
seconds in the stop position. At this
point, there will be an “ACC may cancel
soon” chime and warning to the driver.
When ACC is cancelled, the system will
release the brakes and the driver must
take over braking. The system can be
resumed when the target vehicle drives
off by releasing the brake and pushing
the resume button on the steering
wheel.
WARNING! (Continued)
You should switch off the ACC system:
When driving in fog, heavy rain, heavy
snow, sleet, heavy traffic, and complex
driving situations (i.e., in highway construc -
tion zones).
When entering a turn lane or highway off
ramp; when driving on roads that are
winding, icy, snow-covered, slippery, or
have steep uphill or downhill slopes.
When towing a trailer up or down steep
slopes.
When circumstances do not allow safe
driving at a constant speed.
WARNING! (Continued)
1 — Adaptive Cruise Control On/Off Button
2 — Distance Button
3 — RES (+)
4 — SET (-)
5 — CANCEL
6 — Normal (Fixed Speed) Cruise Control On/Off
Button
5

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STARTING AND OPERATING273
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.
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.
5

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280STARTING 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.
WARNING!
Make certain that the load is secured in the
trailer and will not shift during travel. When
trailering cargo that is not fully secured,
dynamic load shifts can occur that may be
difficult for the driver to control. You could
lose control of your vehicle and have a colli -
sion.
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.
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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SERVICING AND MAINTENANCE375
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 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
7

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376SERVICING AND MAINTENANCE
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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SERVICING AND MAINTENANCE377
Tire Identification Number (TIN)
The 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
7

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378SERVICING AND MAINTENANCE
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 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.
EXAMPLE:

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