tire size RAM CHASSIS CAB 2012 User Guide

Full Size Spare – If Equipped
The full size spare is for temporary emergency use only.
This tire may look like the original 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 equipment 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. In-
stallation of this limited-use spare tire affects vehicle
handling. With this tire, do not drive more than the
speed listed on the limit-use spare wheel. Keep
inflated to the cold tire inflation pressure listed on
your Tire and Loading Information Placard located
on the driver ’s side door opening. 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.326 STARTING AND OPERATING

These indicators are molded into the bottom of the tread
grooves. They will appear as bands when the tread depth
becomes 1/16 in (2 mm). When the tread is worn to the
tread wear indicators, the tire should be replaced.
Many states have laws requiring tire replacement at this
point.
Life Of Tire
The service life of a tire is dependent upon varying
factors including, but not limited to:
• Driving style
• Tire pressure
• Distance driven WARNING!Tires and 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.
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 pressure. The manu-
facturer strongly recommends that you use tires equiva-
lent to the originals in size, quality and performance
when replacement is needed (refer to the paragraph on
“Tread Wear Indicators”). Refer to the “Tire and Loading328 STARTING AND OPERATING

Information” placard 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 original equipment
or an authorized tire 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 or rating other than
that specified for your vehicle. Some combinations
of unapproved tires and wheels may change sus-
pension dimensions and performance characteris-
tics, resulting in changes to steering, handling, and
braking of your vehicle. This can cause unpredict-
able handling and stress to steering and suspen-
sion 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)
5 STARTING AND OPERATING 329

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 result-
ing in serious injury or death.
• Failure to equip your vehicle with tires having
adequate speed capability can result in sudden tire
failure and loss of vehicle control resulting in
serious injury or death.
CAUTION!Replacing original tires with tires of a different size
may result in false speedometer and odometer read-
ings. SUPPLEMENTAL TIRE PRESSURE INFORMATION
— IF EQUIPPED
A light load vehicle condition is defined as two passen-
gers [150 lbs (68 kg) each] plus 200 lbs (91 kg) of cargo.
Cold tire inflation pressures for a lightly loaded vehicle
will be found on the face of the driver’s door.
TIRE CHAINS
Use “Class U” chains or other traction aids that meet SAE
Type “U” specifications.
NOTE: Chains must be the proper size for the vehicle,
as recommended by the chain manufacturer.
CAUTION!To avoid damage to your vehicle, tires or chains,
observe the following precautions:
(Continued)330 STARTING AND OPERATING

• On 4X2 vehicles, class “U” snow chains are permitted
on the rear wheels only of vehicles equipped with
LT245/70R17, LT265/70R17, and LT235/80R17 size
tires.
• On 4X4 Single Rear Wheel (SRW) vehicles, class “U”
snow chains are permitted on the rear wheels only on
vehicles equipped with LT265/70R17.
CAUTION!Do not use tire chains on the 4X2 front wheels of
SRW (Single Rear Wheels) equipped with LT245/
70R17, LT265/70R17 tires or 4X4 front tires of vehicles
equipped with LT265/70R17 tires. There may not be
adequate clearance for the chains and you are risking
structural or body damage to your vehicle. SNOW TIRES
Some areas of the country require the use of snow tires
during the winter. All season tires can be identified by the
M+S designation on the tire sidewall.
If you need snow tires, select tires equivalent in size and
type to the original 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.332 STARTING AND OPERATING

Tire Size
The tire size on the 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 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 commer-
cial scale to insure 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 front and rear axle. Weighing
the vehicle may show that the 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 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.
5 STARTING AND OPERATING 343

WARNING! (Continued)• 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:
1. GVWR
(Continued) WARNING! (Continued)2. GTW
3. GAWR
4. Trailer tongue weight rating for the trailer hitch
utilized (This requirement may limit the ability to
always achieve the 10% to 15% range of tongue
weight as a percentage of total trailer weight).
Towing Requirements – Tires
• Do not attempt to tow a trailer with less than the full
size spare tire.
• Proper tire inflation pressures are essential to the safe
and satisfactory operation of your vehicle. Refer to
“Tires – General Information” in “Starting and Oper-
ating” for proper tire inflation procedures.
• Check the trailer tires for proper tire inflation pres-
sures before trailer usage.352 STARTING AND OPERATING

Synthetic Engine Oil ...................... 408
System, Remote Starting .................... 26
Tachometer ............................ 189
Temperature Control, Automatic (ATC) ........ 260
Temperature Gauge, Engine Coolant .......... 189
Tether Anchor, Child Restraint ............. 68,73
Text Messaging ......................... 115
Tilt Steering Column ..................... 157
Tip Start .............................. 274
Tire and Loading Information Placard ...... 314,330
Tire Identification Number (TIN) ............. 312
Tire Markings .......................... 309
Tire Safety Information .................... 309
Tires ............................ 81,318,479
Aging (Life of Tires) .................. 328
Air Pressure ........................ 318
Chains ............................ 330
Compact Spare ...................... 325 Dual ........................... 334,384
General Information .................. 318
High Speed ......................... 323
Inflation Pressures .................... 319
Life of Tires ........................ 328
Load Capacity .................... 314,315
Quality Grading ..................... 479
Radial ............................ 324
Replacement ........................ 328
Rotation ........................... 333
Safety .......................... 309,318
Sizes ............................. 310
Snow Tires ......................... 332
Spinning ........................... 327
Steel Carcass Ply ..................... 321
Tread Wear Indicators ................. 327
Wheel Nut Torque .................... 382
Tongue Weight/Trailer Weight .............. 349
Torque Converter Clutch .................. 287496 INDEX