tire size Ram 2500 2018 Owner's Guide

pressure should be increased by 3 psi (21 kPa), which
equals 1 psi (7 kPa) for every 12°F (7°C) for this outside
temperature condition.
Tire pressure may increase from 2 to 6 psi (13 to 40 kPa)
during operation. DO NOT reduce this normal pressure
build up or your tire pressure will be too low.
Tire Pressures For High Speed Operation
The manufacturer advocates driving at safe speeds and
within posted speed limits. Where speed limits or condi-
tions are such that the vehicle can be driven at high speeds,
maintaining correct tire inflation pressure is very impor-
tant. Increased tire pressure and reduced vehicle loading
may be required for high-speed vehicle operation. Refer to
your authorized tire dealer or original equipment vehicle
dealer for recommended safe operating speeds, loading
and cold tire inflation pressures.
WARNING!
High speed driving with your vehicle under maximum
load is dangerous. The added strain on your tires could
cause them to fail. You could have a serious collision.
Do not drive a vehicle loaded to the maximum capacity
at continuous speeds above 75 mph (120 km/h).
Radial Ply Tires
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.
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 thana¼ofaninch (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 immedi-
ately with another Run Flat tire of identical size and service
description (Load Index and Speed Symbol).
570 SERVICING AND MAINTENANCE

WARNING!(Continued)
You could lose control and have a collision resulting in
serious injury or death.
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 manu-
facturer 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 Indicators” in this section. Refer to the Tire and
Loading Information 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
original wheels.
It is recommended you contact your 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!
•
Do not use a tire, wheel size, load rating, or speed
rating other than that specified for your vehicle.
Some combinations of unapproved tires and wheels
may change suspension dimensions and perfor-
mance characteristics, resulting in changes to steer-
ing, 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.
(Continued)
8
SERVICING AND MAINTENANCE 573

WARNING!(Continued)
•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 ad-
equate 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.
Tire Types
All Season Tires — If Equipped
All Season tires provide traction for all seasons (Spring,
Summer, Fall, and Winter). Traction levels may vary be-
tween 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 am-
bient 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 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.
574 SERVICING AND MAINTENANCE

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 origi-
nal 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 original
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 stud-
ded tires; therefore, local laws should be checked before
using these tire types.
Spare Tires — If Equipped
NOTE: For vehicles equipped with Tire Service Kit instead
of a spare tire, please refer to “Tire Service Kit” in “In Case
Of Emergency” for further information.
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.
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
8
SERVICING AND MAINTENANCE 575

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.
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
(Continued)
WARNING!(Continued)
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.
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.
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.
576 SERVICING AND MAINTENANCE

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.
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
opportunity.
Limited Use Spare — If Equipped
The limited use spare tire is for temporary emergency 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 equip-
ment tire, replace (or repair) the original equipment tire
and reinstall on the vehicle at the first opportunity.
WARNING!
Limited use spares are for emergency use only. Instal-
lation of this limited use spare tire affects vehicle
handling. With this tire, do not drive more than the
speed listed on the limited use spare wheel. Keep
inflated to the cold tire inflation pressures listed on
your Tire and Loading Information Placard located on
the driver ’s side B-Pillar or the rear edge of the driver ’s
side door. Replace (or repair) the original equipment
tire at the first opportunity and reinstall it on your
vehicle. Failure to do so could result in loss of vehicle
control.8
SERVICING AND MAINTENANCE 577

Dark Vapor Chrome, Black Satin Chrome, or Low Gloss
Clear Coat Wheels
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 US-
ING MILD SOAP AND WATER WITH A SOFT
CLOTH. Used on a regular basis; this is all that is
required to maintain this finish.
Tire Chains (Traction Devices)
Use of traction devices require sufficient tire-to-body clear-
ance. Follow these recommendations to guard against
damage.
•Traction device must be of proper size for the tire, as
recommended by the traction device manufacturer.
Please follow the table below for proper tire size, chain
type, and axle recommendations:
Vehicle Axle Recommendations Tire SizesChain Class
1500 Models Rear OnlyP265/70R17 S Class
2500 Models Rear OnlyLT245/70R17E
LT275/70R18E U Class
2500 Power Wagon Models Rear OnlyLT285/70R17D U Class
3500 (Single Rear Wheel) Models Rear Only
LT275/70R18E U Class
3500 (Dual Rear Wheel) Models Front/Rear
LT235/80R17E U Class
8
SERVICING AND MAINTENANCE 579

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 clearance be-
tween tires and other suspension components, it is
important that only traction devices in good condi-
tion 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 re-
tighten after driving about ½ mile (0.8 km).
• 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 pave-
ment.
(Continued)
CAUTION! (Continued)
•Observe the traction device manufacturer ’s instruc-
tions on the method of installation, operating speed,
and conditions for use. Always use the suggested
operating speed of the device manufacturer ’s if it is
less than 30 mph (48 km/h).
• Do not use traction devices on a compact spare tire.
Tire Rotation Recommendations
Tires on the front and rear axles of vehicles operate at
different loads and perform different steering, driving, and
braking functions. For these reasons, they wear at unequal
rates.
These effects can be reduced by timely rotation of tires. The
benefits of rotation are especially worthwhile with aggres-
sive tread designs such as those on all season type tires.
Rotation will increase tread life, help to maintain mud,
snow and wet traction levels and contribute to a smooth,
quiet ride.
Refer to the “Maintenance Plan” for the proper mainte-
nance intervals. More frequent rotation is permissible if
desired. The reasons for any rapid or unusual wear should
be corrected prior to rotation being performed.
580 SERVICING AND MAINTENANCE

WHEEL AND TIRE TORQUE SPECIFICATIONS
Proper lug nut/bolt torque is very important to ensure that
the wheel is properly mounted to the vehicle. Any time a
wheel has been removed and reinstalled on the vehicle, the
lug nuts/bolts should be torqued using a properly cali-
brated torque wrench using a high quality six sided (hex)
deep wall socket.
Torque Specifications
Lug Nut/
Bolt Torque Lug Nut/
Bolt Type **Lug Nut/
Bolt Size Lug Nut/
Bolt Socket Size
130 Ft-Lbs (176 N·m) Cone M14 x 1.50 22 mm
140 Ft-Lbs (190 N·m) Flanged
**Use only your authorized dealer recommended lug nuts/
bolts and clean or remove any dirt or oil before tightening. 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 lug nut/bolt and the
washer. Do not oil wheel studs.
Two-Piece Lug Nut
594 TECHNICAL SPECIFICATIONS

Steering Wheel Audio Controls.................653
Steering Wheel Mounted Sound System Controls . . . .653
Storage Compartment, Center Seat ..............123
Storage, Vehicle ........................105, 584
Storing Your Vehicle ........................584
Sun Roof .................................110
Suspension, Air ........................344, 350
Sway Control, Trailer ........................213
Synthetic Engine Oil ........................530
Tailgate .................................153
Telescoping Steering Column ...................61
Temperature Control, Automatic (ATC) ...........104
Tilt Down ...............................47, 49
Up .................................47, 49
Tilt Steering Column .........................61
Tip Start .................................289
Tire And Loading Information Placard ............564
Tire Markings ............................ .558
Tires......................... .281, 568, 575, 583
Aging (Life Of Tires) ..................... .572
Air Pressure ............................568
Chains ............................... .579
Changing ............................. .468Compact Spare
..........................575
Dual ............................. .582, 594
General Information ...................568, 575
High Speed ............................ .570
Inflation Pressures ........................569
Jacking ............................... .468
Life Of Tires ............................572
Load Capacity .......................564, 565
Pressure Monitor System (TPMS) .............216
Pressure Warning Light ....................194
Quality Grading ........................ .583
Radial ............................... .570
Replacement ............................573
Rotation ...............................580
Safety ............................ .558,568
Sizes .................................560
Snow

Tires ............................ .575
Spare Tire ..........................575, 577
Spinning ...............................571
Trailer Towing .......................... .425
Tread Wear Indicators .....................572
Wheel Nut Torque ........................594
Tire Safety Information .......................558
Tongue Weight/Trailer Weight .................423
694 INDEX