2020 Ram 1500 wheel size

314 STARTING AND OPERATING
When operating your vehicle in 4WD LOW, the engine
speed is approximately three times that of the 2WD or 4WD
HIGH positions at a given road speed. Take care not to over-
speed 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 circumference on each wheel.
Any difference in tire size can cause damage to the drive -
train.
Because four-wheel drive provides improved traction, there
is a tendency to exceed safe turning and stopping speeds. Do
not go faster than road conditions permit.
Shifting Procedure
NOTE:
• If any of the requirements to select a new transfer case position have not been met, the transfer case will not shift.
The position indicator light for the previous position will
remain ON and the newly selected position indicator light
will continue to flash until all the requirements for the
selected position have been met.
• If all the requirements to select a new transfer case position have been met, the current position indicator light will
turn OFF, the selected position indicator light will flash until the transfer case completes the shift. When the shift is
complete, the position indicator light for the selected posi
-
tion will stop flashing and remain ON.
Five-Position Electronically Shifted Transfer Case
(Eight Speed Transmission Only) — If Equipped
This is an electronic shift transfer case and is operated by the
4WD Control Switch (Transfer Case Switch), which is
located on the instrument panel.
Five-Position/On-Demand Transfer Case — Eight Speed Transmission Only
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318 STARTING AND OPERATING
When operating your vehicle in 4WD LOW, the engine
speed is approximately three times that of the 2WD, 4WD
AUTO or 4WD HIGH 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 circumference on each wheel.
Any difference in tire size can cause damage to the drive-
train.
Because four-wheel drive provides improved traction, there
is a tendency to exceed safe turning and stopping speeds. Do
not go faster than road conditions permit. Shifting Procedure
NOTE:
• If any of the requirements to select a new transfer case
position have not been met, the transfer case will not shift.
The position indicator light for the previous position will
remain ON and the newly selected position indicator light
will continue to flash until all the requirements for the
selected position have been met.
• If all the requirements to select a new transfer case position have been met, the current position indicator light will
turn OFF, the selected position indicator light will flash
until the transfer case completes the shift. When the shift is
complete, the position indicator light for the selected posi -
tion will stop flashing and remain ON.
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STARTING AND OPERATING 343
NOTE:
Any chassis/suspension or tire size modifications to the
vehicle will effect the performance of the Adaptive Cruise
Control and Forward Collision Warning System.
Activating Adaptive Cruise Control (ACC)
You can only engage ACC if the vehicle speed is above
0 mph (0 km/h).
The minimum set speed for the ACC system is 20 mph
(32 km/h).
When the system is turned on and in the ready state, the
instrument cluster display will read “ACC Ready.”
When the system is off, the instrument cluster display will
read “Adaptive Cruise Control (ACC) Off.”NOTE:
You cannot engage ACC under the following conditions:
• When in Four-Wheel Drive Low
• When you apply the brakes
• When the parking brake is applied
• When the automatic transmission is in PARK, REVERSE or
NEUTRAL
• When the vehicle speed is outside of the speed range
• When the brakes are overheated
• When the driver door is open at low speed
• When the driver seat belt is unbuckled at low speed
• ESC Full-Off Mode is active
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406 STARTING AND OPERATING
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 components in the
system with the lowest load carrying capacity (axle, springs,
tires or wheels). Heavier axles or suspension components
sometimes 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 Gross Axle Weight Rating
(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 conditions, 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 insure that the Gross Vehicle Weight Rating (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
axle. Weighing the vehicle may show that the Gross Axle
Weight Rating (GAWR) of either the front or rear axles has
been exceeded but the total load is within the specified
GVWR. If so, weight must be shifted from front to rear or
rear to front as appropriate until the specified weight limita-
tions are met. Store the heavier items down low and be sure
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STARTING AND OPERATING 409

If equipped, the electronic TSC recognizes a swaying trailer
and automatically 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
accordance with the manufacturer's directions, it provides
for a more level ride, offering more consistent steering and
brake control, thereby enhancing towing safety. The addi-
tion of a friction/hydraulic sway control also dampens sway
caused by traffic and crosswinds and contributes positively
to tow vehicle and trailer stability. Trailer sway control and
a weight distributing (load equalizing) hitch are recom -
mended for heavier Tongue Weights (TW) and may be
required depending on vehicle and trailer configuration/
loading to comply with GAWR requirements. Without Weight-Distributing Hitch (Incorrect)WARNING!
• An improperly adjusted weight distributing hitch system may reduce handling, stability and braking
performance and could result in a collision.
• Weight distributing systems may not be compatible with surge brake couplers. Consult with your hitch and
trailer manufacturer or a reputable Recreational
Vehicle dealer for additional information.
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530 SERVICING AND MAINTENANCE
NOTE:
Wheel Valve Stem must be replaced as well when installing
new tires due to wear and tear in existing tires.
Keep dismounted tires in a cool, dry place with as little expo-
sure to light as possible. Protect tires from contact with oil,
grease, and gasoline.
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 that you use tires equivalent to the
originals in size, quality and performance when replacement
is needed. Refer to the paragraph on “Tread Wear Indica -
tors” in this section. Refer to the Tire and Loading Informa -
tion 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.
See the Tire Sizing Chart example found in the “Tire Safety
Information” section of this manual for more information
relating to the Load Index and Speed Symbol of a tire.
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 orig
-
inal 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.
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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SERVICING AND MAINTENANCE 531
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 condi-
tions, 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 tempera -
tures 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 combi -
nations of unapproved tires and wheels may change
suspension dimensions and performance characteris -
tics, resulting in changes to steering, handling, and
braking of your vehicle. This can cause unpredictable
handling and stress to steering and suspension compo -
nents. 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.
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SERVICING AND MAINTENANCE 533
Spare Tire Matching Original Equipped Tire And Wheel
— If Equipped
Your vehicle may be equipped with a spare tire and wheel
equivalent in look and function to the original equipment
tire and wheel found on the front or rear axle of your vehicle.
This spare tire may be used in the tire rotation for your
vehicle. If your vehicle has this option, refer to an authorized
tire dealer for the recommended tire rotation pattern.
Compact Spare Tire — If Equipped
The compact spare is for temporary emergency use only.
You can identify if your vehicle is equipped with a compact
spare by looking at the spare tire description on the Tire and
Loading Information Placard located on the driver’s side
door opening or on the sidewall of the tire. Compact spare
tire descriptions begin with the letter “T” or “S” preceding
the size designation. Example: T145/80D18 103M.
T, S = Temporary Spare Tire
Since this tire has limited tread life, the original equipment
tire should be repaired (or replaced) and reinstalled on your
vehicle at the first opportunity.
Do not install a wheel cover or attempt to mount a conven-
tional tire on the compact spare wheel, since the wheel is designed specifically for the compact spare tire. Do not
install more than one compact spare tire and wheel on the
vehicle at any given time.
Collapsible Spare Tire — If Equipped
The collapsible spare is for temporary emergency use only.
You can identify if your vehicle is equipped with a collaps
-
ible spare by looking at the spare tire description on the Tire
and Loading Information Placard located on the driver’s side
door opening or on the sidewall of the tire.
Collapsible spare tire description example: 165/80-17 101P.
Since this tire has limited tread life, the original equipment
tire should be repaired (or replaced) and reinstalled on your
vehicle at the first opportunity.
WARNING!
Compact and collapsible spares are for temporary
emergency use only. With these spares, do not drive
more than 50 mph (80 km/h). Temporary use spares have
limited tread life. When the tread is worn to the tread
wear indicators, the temporary use spare tire needs to be
replaced. Be sure to follow the warnings, which apply to
your spare. Failure to do so could result in spare tire
failure and loss of vehicle control.
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