Dodge 2500 Diesel (2008 year). Instruction — part 21

Tire Pressures for High Speed Operation
The manufacturer advocates driving at safe speeds
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
important. Increased tire pressure and reduced vehicle
loading may be required for high-speed vehicle opera-
tion. Refer to original equipment or an authorized tire
dealer for recommended safe operating speeds, loading
and cold tire inflation pressures.

WARNING!

High speed driving with your vehicle under maxi-
mum load is dangerous. The added strain on your
tires could cause them to fail. You could have a
serious accident. Don’t 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 an accident. Al-
ways use radial ply tires in sets of four (or six, in case
of trucks with dual rear wheels). Never combine
them with other types of tires.

Cuts and punctures in radial tires are repairable only in
the tread area because of sidewall flexing. Consult your
authorized tire dealer for radial tire repairs.

STARTING AND OPERATING

327

5

Compact Spare Tire — If Equipped

The compact spare is for temporary emergency use with
radial tires. It is engineered to be used on your style
vehicle only. Since this tire has limited tread life, the
original tire should be repaired (or replaced) and rein-
stalled at the first opportunity.

WARNING!

Temporary use spare tires are for emergency use only.
With these tires, do not drive more than 50 mph (80
km/h). Temporary use spare tires 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.

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.

Do not install more than one compact spare tire/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 the
compact spare installed. Damage to the vehicle may
result.

Limited-Use Spare — If Equipped

The limited-use spare tire is for temporary emergency
use on your vehicle. This tire is identified by a limited-
use spare tire warning label located on the limited-use
spare tire and wheel assembly. This tire may look like the

328

STARTING AND OPERATING

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 tire,
replace (or repair) the original tire and reinstall on the
vehicle at the first opportunity.

WARNING!

The limited-use spare tires are for emergency use
only. Installation of this limited-use spare tire affects
vehicle handling. With this tire, do not drive more
than 50 mph (80 km/h). Keep inflated to the cold tire
inflation pressure listed on either your tire placard or
limited-use spare tire and wheel assembly. Replace
(or repair) the original tire at the first opportunity
and reinstall it on your vehicle. Failure to do so could
result in loss of vehicle control.

Tire Spinning

When stuck in mud, sand, snow, or ice conditions, do not
spin your vehicle’s wheels faster than 30 mph (48 km/h)
or for longer than 30 seconds continuously without
stopping when you are stuck.

For additional information, refer to “Freeing A Stuck
Vehicle” in Section 6.

WARNING!

Fast spinning tires can be dangerous. Forces gener-
ated by excessive wheel speeds may cause tire dam-
age or failure. A tire could explode and injure some-
one. Do not spin your vehicle’s wheels faster than 30
mph (48 km/h) or for more than 30 seconds continu-
ously when you are stuck, and don’t let anyone near
a spinning wheel, no matter what the speed.

STARTING AND OPERATING

329

5

Tread Wear Indicators

Tread wear indicators are in the original equipment tires
to help you in determining when your tires should be
replaced.

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

330

STARTING AND OPERATING

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 an accident 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 Loading
Information” placard for the size designation of your tire.
The service description and load identification will be
found on the original equipment tire. Failure to use
equivalent replacement tires may adversely affect the
safety, handling, and ride of your vehicle. We recommend
that you contact your original equipment or an autho-
rized tire dealer with any questions you may have on tire
specifications or capability.

STARTING AND OPERATING

331

5

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 suspension
dimensions and performance characteristics, result-
ing 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 an accident 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 an accident.

• 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.

Alignment and Balance

Poor suspension alignment may result in:

• Fast tire wear.
• Uneven tire wear, such as feathering and one-sided

wear.

• Vehicle pull to right or left.

Tires may also cause the vehicle to pull to the left or right.
Alignment will not correct this condition. See your
authorized dealer for proper diagnosis.

332

STARTING AND OPERATING

Improper alignment will not cause vehicle vibration.
Vibration may be a result of tire and wheel out-of-
balance. Proper balancing will reduce vibration and
avoid tire cupping and spotty wear.

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 on 2500/3500 Ram Trucks, 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:
• Because of limited chain clearance between tires and other

suspension components, it is important that only chains in good
condition are used. Broken chains can cause serious vehicle
damage. Stop the vehicle immediately if noise occurs that could
suggest chain breakage. Remove the damaged parts of the chain
before further use.

• Install chains as tightly as possible and then retighten after

driving about 1/2 mile (0.8 km).

• Do not exceed 45 mph (72 km/h).
• Drive cautiously and avoid severe turns and large bumps,

especially with a loaded vehicle.

• Do not install tire chains on front wheels of 4x2 vehicles.
• Do not drive for a prolonged period on dry pavement.
• Observe the tire chain manufacturer’s instructions on method of

installation, operating speed, and conditions for usage. Always
use the lower suggested operating speed of the chain manufac-
turer if different than the speed recommended by the
manufacturer.

STARTING AND OPERATING

333

5

These cautions apply to all chain traction devices, includ-
ing link and cable (radial) chains.

Tire chain use is permitted only on the rear tires of Ram
4X2 trucks.

NOTE:

The use of class “U” chains is permitted on the

front and rear of 4X4, 2500 Ram Trucks with LT245/
70R17E tires.

NOTE:

The use of class “U” chains is permitted on the

front and rear of 4X4, 3500 Ram Trucks with Dual Rear
Wheels and LT235/80R17E tires.

NOTE:

On 4X2 2500/3500 Ram Trucks, class “U” snow

chains are permitted on the rear wheels only of vehicles
equipped with LT245/70R17, LT265/70R17, and LT235/
80R17 size tires.

NOTE:

On 4X4 2500/3500 Single Rear Wheel (SRW)

Ram Trucks, class “U” snow chains are permitted on the
rear wheels only of vehicles equipped with LT265/70R17.

CAUTION!

Do not use tire chains on 4x4 Ram trucks equipped
with P265/70R17, LT275/70R17 tires. There may not
be adequate clearance for the chains and you are
risking structural or body damage to your vehicle. Do
not use tire chains on the 4X2 front wheels of
2500/3500 SRW (Single Rear Wheels) equipped with
LT245/70R17, LT265/70R17 tires or 4X4 front tires of
Ram Trucks equipped with LT265/70R17tires. There
may not be adequate clearance for the chains and you
are risking structural or body damage to your vehicle.

334

STARTING AND OPERATING

SNOW TIRES

Snow tires should be of the same size and type construc-
tion as the front tires. Consult the manufacturer of the
snow tire to determine any maximum vehicle speed
requirement associated with the tire. These tires should
always be operated at the vehicle maximum capacity
inflation pressures under any load condition.

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 pro-
hibit studded tires; therefore, local laws should be
checked before using these tire types.

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 and develop irregular wear patterns. These
effects can be reduced by timely rotation of tires. The
benefits of rotation are especially worthwhile with ag-
gressive tread designs such as those on ON/OFF Road
type tires. Rotation will increase tread life, help to main-
tain mud, snow, and wet traction levels, and contribute to
a smooth, quiet ride.

STARTING AND OPERATING

335

5

Follow the recommended tire rotation frequency for your
type of driving found in the “Maintenance Schedules”
Section of this instruction. More frequent rotation is permis-
sible if desired. The reasons for any rapid or unusual
wear should be corrected prior to rotation being per-
formed.

NOTE:

On Canadian vehicles only, if your vehicle is

equipped with All-Season type tires on the front and
ON/OFF Road type tires mounted on the rear, do not use
a front-to-back rotation pattern. Instead, rotate your tires
side-to-side at the recommended intervals.

336

STARTING AND OPERATING

Dual Rear Wheels

The tires used on dual wheel assemblies should be
matched for wear to prevent overloading one tire in a set.
To check if tires are even, lay a straight edge across all
four tires. The straight edge should touch all the tires.

CAUTION!

3500 Dual Rear Tires have only one approved direc-
tion of rotation. This is to accommodate the asym-
metrical design (tread pattern) of the ON/OFF road
tire and the use of Outline White Letter (OWL) tires.
• When replacing a flat, the spare tire may have to

be remounted on the rim, or installed at a different
location, to maintain the correct placement of the
tire on the wheel relative to the tire/wheel position
on the truck. For example, if the spare is used to
replace an outer rear tire it will have to be re-
mounted on the rim so that the wheel is dished
inward. That way the tread design of asymmetrical
tires and the white writing of the OWL tires will
maintain proper position.

STARTING AND OPERATING

337

5

TIRE PRESSURE MONITOR SYSTEM (TPMS) — IF
EQUIPPED

The Tire Pressure Monitoring System (TPMS) will warn
the driver of a low tire pressure based on the vehicle
recommended cold tire inflation placard pressure. The
placard pressure is defined on the Tire and Loading
Information label. The Tire and Loading Information
label is located on the drivers side B-pillar. Vehicles
equipped to be operated in either the “max load inflation
pressure” condition described on the Tire and Loading
Information label or the alternative “light load inflation
pressure” condition described on the Supplemental Tire
Pressure Information label, may also be equipped with a
reset switch to choose the appropriate TPMS low pres-
sure warning threshold levels based upon the vehicle
load condition. The Supplemental Tire Pressure Informa-
tion label is located on the rear face of the driver door.
Operation of the “Light Load” reset switch is described
later in this instruction section.

The tire pressure will vary with temperature by approxi-
mately 1 psi (6.9 kPa) for every 12°F (6.5°C). This means
that when the outside temperature decreases, the tire
pressure will decrease. Tire pressure should always be set
based on cold inflation tire pressure. This is defined as
the tire pressure after a vehicle has not been driven for
more than 3 hours, or driven less than 1 mile after a 3
hour period. For information on how to properly inflate
the vehicle’s tires, refer to ”Tire Pressure” under “Tires –
General Information” in this section. The tire pressure
will also increase as the vehicle is driven - this is normal
and there should be no adjustment for this increased
pressure.

The TPM System will warn the driver of a low tire
pressure if the tire pressure falls below the low pressure
warning threshold for any reason, including low tem-
perature effects, or natural pressure loss through the tire.

338

STARTING AND OPERATING

The TPM System will continue to warn the driver of low
tire pressure as long as the condition exists, and will not
turn off until the tire pressure is at or above recom-
mended cold placard pressure. Once the low tire pressure
warning has been illuminated, the tire pressure must be
increased to the recommended cold placard pressure in
order for the TPMS warning lamp to be turned off. The
system will automatically update and the TPMS warning
lamp will extinguish once the updated tire pressures
have been received. The vehicle may need to be driven
for up to 10 minutes above 15 mph (25 km/h) to receive
this information.

As an example, assume your vehicle has a recommended
cold tire inflation placard pressure (parked for more than
3 hours) of 35 psi (241 kPa). If the ambient temperature is
68°F (20°C) and the measured tire pressure is 30 psi (207
kPa), a temperature drop to 20°F (-7°C) will decrease the
tire pressure to approximately 26 psi (179 kPa). This tire
pressure is sufficiently low enough to turn ON the Tire

Pressure Monitoring lamp. Driving the vehicle may cause
the tire pressure to rise to approximately 30 psi (207 kPa),
but the Tire Pressure Monitoring lamp will still be ON. In
this situation, the Tire Pressure Monitoring lamp will
turn OFF only after the tires have been inflated to the
vehicle’s recommended cold tire placard pressure value.

CAUTION!

The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures have
been established for the tire size equipped on your
vehicle. Undesirable system operation or sensor
damage may result when using replacement equip-
ment that is not of the same size, type, and/or style.
After-market wheels can cause sensor damage. Do
not use aftermarket tire sealants or balance beads if
your vehicle is equipped with a TPMS, as damage to
the sensors may result.

STARTING AND OPERATING

339

5

CAUTION!

After inspecting or adjusting the tire pressure always
reinstall the valve stem cap. This will prevent mois-
ture and dirt from entering the valve stem, which
could damage the Tire Pressure Monitoring Sensor.

NOTE:

• The TPMS is not intended to replace normal tire care

and maintenance, nor to provide warning of a tire
failure or condition.

• The TPMS should not be used as a tire pressure gauge

while adjusting your tire pressure.

• Driving on a significantly under-inflated tire causes

the tire to overheat and can lead to tire failure.
Under-inflation also reduces fuel efficiency and tire
tread life, and may affect the vehicle’s handling and
stopping ability.

• The TPMS is not a substitute for proper tire mainte-

nance, and it is the driver’s responsibility to maintain
correct tire pressure, even if under-inflation has not
reached the level to trigger illumination of the “Tire
Pressure Monitoring Telltale Light.”

• Seasonal temperature changes will affect tire pressure,

and the TPM system will monitor the actual tire
pressure in the tire.

340

STARTING AND OPERATING

Tire Pressure Monitor System (TPMS) “Light
Load” Reset Switch Description – If Equipped

WARNING!

Never operate your vehicle with the TPMS and tire
pressures set to the Light Load Inflation Pressure
settings if carrying more than two occupants (150 lbs
each) plus 200 pounds of cargo. The vehicle “Light
Load Definition” is found in the Supplemental Tire
Pressure Information Label which is located on the
rear face of the driver door. Failure to do so may
cause you to lose control resulting in an accident,
causing serious or fatal injury.

The TPMS “Light Load” reset switch will allow the driver
to switch between the max load inflation pressure (cold)
low pressure warning threshold and the light load infla-
tion pressure (cold) low pressure warning threshold
depending on the vehicle’s load condition. The Tire and
Loading Information label defines the recommended
front and rear cold tire inflation pressures for the vehicle
when operating in the Max Load condition. A Supple-
mental Tire Pressure Information label is also available
defining Light Load tire inflation pressures when oper-
ating in the Light Load condition. When the “Light Load”
reset switch LED is ON, the TPMS is using the light load
inflation pressure (cold) low inflation warning thresh-
olds.

STARTING AND OPERATING

341

5

“Light Load” Reset Switch Operation – If
Equipped

• This vehicle may have different recommended tire

pressure values between the front and rear tires as
shown in both the Tire Loading Information Label and
the Supplemental Tire Pressure Information Label. It is
also equipped to be driven with tire pressures appro-
priate to either a Light Load condition or the vehicle
Max Load condition.

• The “Light Load” reset switch will allow the driver to

change between the max load inflation pressure (cold)
low pressure warning threshold and the light load
inflation pressure (cold) low pressure warning thresh-
old depending on the vehicle’s load condition. Refer to
the “Supplemental Tire Pressure Information” label for
the vehicle’s Light Load inflation pressures and “Tire
and Loading Information” label for the vehicle’s Max
Load inflation pressures.

Light Load Reset Switch

342

STARTING AND OPERATING