wheel size RAM CHASSIS CAB 2020 User Guide

STARTING AND OPERATING275
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 (TSC)
The TSC 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 tele -
scoping motion to dampen any unwanted trailer
swaying motions while traveling.
If equipped, the electronic TSC recognizes a
swaying trailer and automatically applies indi -
vidual 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
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 manufac-
turer or a reputable Recreational Vehicle
dealer for additional information.
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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384SERVICING AND MAINTENANCE
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 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.
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.
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.

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SERVICING AND MAINTENANCE385
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

These indicators are molded into the bottom of
the tread grooves. They will appear as bands
when the tread depth becomes a 1/16 of an
inch (1.6 mm). When the tread is worn to the
tread wear indicators, the tire should be
replaced.
Refer to “Replacement Tires” in this section for
further information.
Life Of Tire
The service life of a tire is dependent upon
varying factors including, but not limited to:
Driving style.
Tire pressure - Improper cold tire inflation
pressures can cause uneven wear patterns
to develop across the tire tread. These
abnormal wear patterns will reduce tread life,
resulting in the need for earlier tire replace -
ment.
Distance driven.
Performance tires, tires with a speed rating of
V or higher, and Summer tires typically have
a reduced tread life. Rotation of these tires
per the vehicle scheduled maintenance is
highly recommended. 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 exposure 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 equiva-
lent to the originals in size, quality and perfor
-
mance when replacement is needed. Refer to
the paragraph on “Tread Wear Indicators” in
this section. Refer to the Tire and Loading Infor -
mation 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.
1 — Worn Tire
2 — New Tire
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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386SERVICING AND MAINTENANCE
(Continued)
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 replace -
ment 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 unap
-
proved tires and wheels may change
suspension dimensions and performance
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! (Continued)
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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SERVICING AND MAINTENANCE387
Snow Tires
Some areas of the country require the use of
snow tires during the Winter. Snow tires can be
identified by a “mountain/snowflake” symbol
on the tire sidewall.
If you need snow tires, select tires
equivalent in size and type to the orig -
inal equipment tires. Use snow tires
only in sets of four; failure to do so
may adversely affect the safety and handling of
your vehicle.
Snow tires generally have lower speed ratings
than what was originally equipped with your
vehicle and should not be operated at
sustained speeds over 75 mph (120 km/h). For
speeds above 75 mph (120 km/h) refer to orig -
inal equipment or an authorized tire dealer for
recommended safe operating speeds, loading
and cold tire inflation pressures.
While studded tires improve performance on
ice, skid and traction capability on wet or dry
surfaces may be poorer than that of
non-studded tires. Some states prohibit
studded tires; therefore, local laws should be
checked before using these tire types.
Spare Tires — If Equipped
Refer to the “Towing Requirements - Tires” in
“Starting And Operating” for restrictions when
towing with a spare tire designated for tempo -
rary emergency use.
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 autho -
rized tire dealer for the recommended tire rota -
tion 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 conventional 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.CAUTION!
Because of the reduced ground clearance, do
not take your vehicle through an automatic
car wash with a compact or limited use
temporary spare installed. Damage to the
vehicle may result.
7

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388SERVICING AND MAINTENANCE
Collapsible Spare Tire — If Equipped
The collapsible spare is for temporary emer -
gency use only. You can identify if your vehicle is
equipped with a collapsible 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. Inflate collapsible tire only after the wheel is
properly installed to the vehicle. Inflate the
collapsible tire using the electric air pump
before lowering the vehicle.
Do not install a wheel cover or attempt to mount
a conventional tire on the collapsible spare
wheel, since the wheel is designed specifically
for the collapsible spare tire.
Full Size Spare — If Equipped
The full size spare is for temporary emergency
use only. This tire may look like the originally
equipped tire on the front or rear axle of your
vehicle, but it is not. This spare tire may have
limited tread life. When the tread is worn to the
tread wear indicators, the temporary use full
size spare tire needs to be replaced. Since it is
not the same as your original equipment tire,
replace (or repair) the original equipment tire
and reinstall on the vehicle at the first opportu
-
nity.
Limited Use Spare — If Equipped
The limited use spare tire is for temporary emer -
gency use only. This tire is identified by a label
located on the limited use spare wheel. This
label contains the driving limitations for this
spare. This tire may look like the original
equipped tire on the front or rear axle of your
vehicle, but it is not. Installation of this limited
use spare tire affects vehicle handling. Since it
is not the same as your original equipment tire,
replace (or repair) the original equipment tire
and reinstall on the vehicle at the first opportu -
nity.
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.
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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390SERVICING AND MAINTENANCE
(Continued)
Dark Vapor Chrome, Black Satin Chrome, or
Low Gloss Clear Coat Wheels
Tire Chains and Traction Devices
Use of traction devices require sufficient
tire-to-body clearance. Due to limited clearance,
the following traction devices are recom-
mended. Follow these recommendations to
guard against damage.
Traction device must be of proper size for the
tire, as recommended by the traction device
manufacturer.
No other tire sizes are recommended for use
with a tire chain or traction device. Chassis Cab 3500 (Single Rear Wheel) Models
Install on rear tires only.
For LT275/70R18E tire, use of a U-class
snow chain is recommended.
Chassis Cab 3500 4x2 (Dual Rear Wheel)
Models
Install on rear tires only.
For a LT235/80R17E tire, use of a U-class
snow chain is recommended.
Chassis Cab 3500 4x4 (Dual Rear Wheel)
Models
Install on front/rear tires.
For a LT235/80R17E tire, use of a U-class
snow chain is recommended.
Chassis Cab 4500/5500 Models
Install on rear tires only.
For a 225/70R19.5G tire, use of a U-class
snow chain is recommended.
CAUTION!
If your vehicle is equipped with these
specialty wheels, DO NOT USE wheel
cleaners, abrasives, or polishing compounds.
They will permanently damage this finish and
such damage is not covered by the New
Vehicle Limited Warranty. HAND WASH ONLY
USING MILD SOAP AND WATER WITH A SOFT
CLOTH. Used on a regular basis; this is all that
is required to maintain this finish.
WARNING!
Using tires of different size and type (M+S,
Snow) between front and rear axles can
cause unpredictable handling. You could lose
control and have a collision.
CAUTION!
To avoid damage to your vehicle or tires,
observe the following precautions:
Because of restricted traction device clear -
ance between tires and other suspension
components, it is important that only trac-
tion devices in good condition are used.
Broken devices can cause serious damage.
Stop the vehicle immediately if noise
occurs that could indicate device breakage.
Remove the damaged parts of the device
before further use.
Install device as tightly as possible and
then retighten after driving about 0.5 mile
(0.8 km). Autosock devices do not require
retightening.
Do not exceed 30 mph (48 km/h).
Drive cautiously and avoid severe turns and
large bumps, especially with a loaded
vehicle.
Do not drive for a prolonged period on dry
pavement.

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398TECHNICAL SPECIFICATIONS
Torque Specifications
**Use only authorized dealer recommended
lug nuts/bolts and clean or remove any dirt or
oil before tightening.
Inspect the wheel mounting surface prior to
mounting the tire and remove any corrosion or
loose particles.
NOTE:
Dual wheels are flat mounted, center piloted.
The lug nuts are a two-piece assembly. When
the tires are being rotated or replaced, clean
these lug nuts and add two drops of oil at the interface between the hex and the washer.
Ensure that the socket is fully engaged on the
lug nut/bolt (do not insert it half way).

Oil Interface Location

Do not oil wheel studs. For chrome wheels, do
not substitute with chrome plated wheel nuts.

Wheel Mounting Surface
Retighten the wheel nuts in the same sequence
to the torques listed in the table. Go through the
sequence a second time to verify that specific
torque has been achieved. Retighten to specifi
-
cations after 25 miles (40 km) and check the
lug nut/bolt torque to be sure that all the lug
nuts/bolts are properly seated against the
wheel.

8/10 Lug Nuts/Bolts Torque Patterns

It is recommended that wheel stud nuts be kept
torqued to specifications at all times. Torque
wheel stud nuts to specifications at each lubri -
cation interval.
Lug Nut/
Bolt
Torque
Lug Nut/
Bolt Type
**Lug
Nut/Bolt
SizeLug Nut/
Bolt
Socket
Size
120-150 Ft-Lbs
(160-200 N·m) Cone
M14 x 1.50 22 mm
130-160
Ft-Lbs
(190-220 N·m) Flanged
1 — 10 Bolt Pattern
2 — 8 Bolt Pattern

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511
Snow Chains (Tire Chains)
.......................390Snow Plow...........................................286Snow Tires...........................................387Spare Tires...................................387, 388Spark Plugs..........................................407Speed Control Accel/Decel......................................231Cancel.............................................231Resume...........................................231Speed Control (Cruise Control)..........230, 232Starting............................... 183, 184, 187Automatic Transmission............... 183, 187Button...............................................17Cold Weather....................................187Engine Block Heater...........................190Engine Fails To Start...........................186Starting And Operating............................184Starting Procedures........................184, 187Starting Procedures (Diesel Engines)..........187Starting Procedures (Gas Engines).............183SteeringPower..............................................229Tilt Column.........................................38Wheel, Heated.....................................38Wheel, Tilt..........................................38Steering Wheel Audio Controls..................481Steering Wheel Mounted Sound
System Controls....................................481Storage.................................................72Storage Compartment, Center Seat..............73
Storage, Vehicle.............................. 63, 393Storing Your Vehicle............................... 393Sunglasses Storage................................. 81Sway Control, Trailer.............................. 127Synthetic Engine Oil............................... 349
T
Telescoping Steering Column..................... 38Temperature Control, Automatic (ATC).......... 62TiltDown................................................ 31Up.................................................... 31Tilt Steering Column................................. 38Tip Start...................................... 183, 188Tire And Loading Information Placard......... 379Tire Markings....................................... 375Tire Safety Information........................... 374Tires........................... 182, 382, 387, 392Aging (Life Of Tires)............................ 385Air Pressure...................................... 382Chains............................................. 390Changing......................................... 314Compact Spare................................. 387Dual............................... 317, 391, 398General Information................... 382, 387High Speed....................................... 383Inflation Pressure............................... 383Jacking............................................ 314Life Of Tires...................................... 385Load Capacity................................... 379
Pressure Monitoring System(TPMS)................................ 113, 132Quality Grading................................. 392Radial............................................. 384Replacement.................................... 385Rotation.......................................... 391Safety..................................... 374, 382Sizes.............................................. 376Snow Tires....................................... 387Spare Tires.............................. 387, 388Spinning.......................................... 384Trailer Towing................................... 280Tread Wear Indicators......................... 385Wheel Nut Torque.............................. 397To Open Hood........................................ 66Tongue Weight/Trailer Weight.................. 279Torque Converter Clutch......................... 212Towing........................................ 274, 326Disabled Vehicle................................ 326Guide.............................................. 279Recreational..................................... 288Weight............................................ 279Towing Behind A Motorhome................... 288Traction.............................................. 292Traction Control.................................... 124Traction Control Switch........................... 124Trailer Sway Control (TSC)....................... 127Trailer Towing....................................... 274Cooling System Tips........................... 285Hitches........................................... 278
11

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