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The
certification label-
Recreational
vehicles manufactured since 1972 have a certification
label which provides the following information relating
to tires and loads:
- 1.
Gross Vehicle Weight Rating (GVWR)
-
2. Gross Axle Weight Ratings (GAWR) for each axle
- 3.
Tire and rim sizes
- 4.
Recommended cold tire inflation pressures
The
certification label can be found on several different
locations within your vehicle, including (but not
limited to) the driver's hinge pillar, door latch
post, etc. Vehicles manufactured before 1972 may
not have a certification label, and the tire and
loading information will only be found in the owner's
manual. Your manual also contains information about
alternate tire sizes. Be sure to follow all recommendations
in your owner's manual regarding the use of these
alternative tire sizes. If you are considering changing
to a tire size other than those shown on the certification
label, be sure to consult with your vehicle manufacturer,
tire dealer or tire manufacturer. Using the wrong
size tire can lead to tire failure. Vehicle modifications
such as lift kits and other suspension alterations
and/or use of tires not recommended by the vehicle
or tire manufacturer can adversely affect vehicle
handling and stability. Tires specifically designed
for travel trailer use in highway service have an
"ST" molded on the tire sidewall, such as ST225/75R15.
The "ST" stands for "Special Trailer" and means
the tire is designed specifically for trailer service.
Proper
RV Tire Inflation-
The
most important factors in tire care are maintaining
proper inflation pressures, avoiding excess loading,
inspecting tires regularly and driving with care
at appropriate speeds.
It
is important that your tires be properly inflated.
Failure to maintain correct inflation pressures
may result in fast and uneven treadwear, improper
vehicle handling, and excessive heat buildup, which
may result in tire failure.
To
make sure you maintain the correct pressure in your
tires, check the air pressure regularly with your
own dual-head inflation gauge that is calibrated
up to 120 psi at 2 psi increments. The recommended
inflation pressures for your tires are indicated
on the certification label or in your owner's manual.
However, since RVs can be configured and loaded
in many different ways, the proper inflation pressure
should be determined by actual tire loads. The actual
loads can be determined by physically weighing the
vehicle. These loads will change from trip to trip,
depending on how the vehicle is loaded.
WARNING!
Serious
Injury May Result From:
Tire
Failure Due to Underinflation/Overloading Follow
owner's manual or certification label in vehicle
Explosion
of tire/rim assembly due to improper mounting Only
specially trained persons should mount tires.
Check
your tires' air pressures at least once a month,
before each trip, and each morning you drive during
a trip. Inflation pressures should be checked when
tires are "cold," that is, before they have been
driven one mile. Heat generated during driving increases
air pressure above the proper cold inflation pressure.
This is normal, so never "bleed" air from a hot
tire, since this could result in dangerous under
inflation.
It
may be difficult to check the air pressures of inside
tires in dual fitments. (A dual fitment is two tires
on the same side of an axle.) However, it is important
that these air pressures be maintained because the
inside dual tires are subjected to high heat exposure
(from brakes), lower air circulation and crowned
road surfaces (which can cause inside dual tires
to support more of the load than the outside dual
tires).
Make
sure all tire valves and extensions are equipped
with valve caps to keep out dirt and moisture. Installing
a new valve assembly is good practice whenever a
tire is replaced.
How
overloading affects your tires-
The
results of overloading can have serious consequences
in terms of passenger safety. Too much weight for
your vehicle's suspension system can cause spring,
shock absorber or brake failure, handling or steering
problems, irregular tire wear, tire failure or other
damage. An overloaded vehicle is hard to drive and
hard to stop. In cases of serious overloading, brakes
can fail completely, particularly on steep hills.
The load a tire will carry safely is a combination
of the size of the tire, its load range and corresponding
inflation pressure. Overloading your RV, with under
inflated tires, can spell trouble.
Excessive
loads and/or under inflation cause "tire overloading."
As a result, abnormal tire flexing occurs, which
can generate an excessive amount of heat within
the tire. Excessive heat may exceed the tire's capabilities,
which may lead to tire failure.
It
is the air pressure which enables a tire to support
the load, so proper inflation is critical. Since
RVs can be configured and loaded in many different
ways, air pressures must be determined from the
actual loads (determined by weighing) and taken
from the load and inflation tables provided by the
tire manufacturer. These air pressures may differ
from those found on the certification label. However,
they should never exceed the tire limitation for
load or air pressure.
If
you discover that your tires cannot support the
actual weights, lighten the load or install tires
with a higher carrying capacity.
Note:
Installing tires with a higher carrying capacity
only solves the problem of tire overload. It has
no effect on the overloading of other components
(i.e., rims, axles, shocks, or bearings). Rims may
not be capable of withstanding the higher pressures
necessary to support the load.
If
the load cannot be adequately reduced, contact the
RV manufacturer for advice.
If
you decide to install a tire size other than that
originally provided on the vehicle, care must be
taken to ensure adequate load-carrying capacity
and compatibility between the tire and rim.
WARNING!
There
is a danger of serious injury or death if a tire
of one bead diameter is installed on a rim or wheel
of a different rim diameter. Always replace a tire
with another tire of exactly the same bead diameter
designation and suffix letters. For example: A 16"
tire goes on a 16" rim. Never mount a 16" tire on
a 16.5" rim. A 16.5" tire goes on a 16.5" rim. Never
mount a 16.5" tire on a 16" rim.
While
it is possible to pass a 16" diameter tire over
the lip of flanges of a 16.5" size rim, it cannot
be inflated enough to position itself against the
rim flange. If an attempt is made to seat the tire
bead by inflating, the tire bead will break with
explosive force and could cause serious injury or
death.
If
you have operated your vehicle with an under inflated
tire, promptly have it removed from the wheel for
a complete internal inspection to be sure it is
not damaged. Tires driven even short distances while
under inflated may be damaged beyond repair.
Tires
should be inspected regularly for excessive or irregular
tread wear, bulges, aging, fabric breaks, cuts or
other damages. Remove any nails, stones, glass,
etc., embedded in the tread to prevent damage. Even
minor damage can lead to tire failure. Replace tires
when the tread is worn to 2/32" depth remaining
in two or more adjacent grooves.
On
vehicles with GVWR in excess of 10,000 pounds, federal
regulations require that tires on the front axle
be removed when worn down to 4/32" depth. It may
also be desirable to replace tires prior to wearing
down to 4/32" to improve traction or vehicle handling.
Load
and cold inflation pressure imposed on a rim/wheel
must not exceed the rim/wheel manufacturer's recommendation,
even though the tire may be marked for a higher
load and inflation.
Matching
radial tires with rim/wheels must be done with extreme
care. Not all older rims/wheels are approved for
use with radial tires. Consult the rim/wheel manufacturer
or local distributor or your tire dealer, to determine
which rims/wheels are acceptable for use with a
specific radial tire.
If
your tires show uneven wear, ask a serviceperson
to check for and correct any misalignment, imbalance,
or other mechanical problem involved.
Tires
will wear out faster when subjected to high speeds
as well as hard cornering, rapid starts, sudden
stops and frequent driving on surfaces which are
in poor condition. Surfaces with holes and rocks
or other objects can damage tires and cause wheel
misalignment. When you drive on such surfaces, drive
on them carefully and slowly. Before driving at
normal or highway speeds, examine your tires for
any damage, such as cuts or penetrations.
Check
your tires frequently for scrapes, bulges, cuts,
snags, or impact damage. Damage can occur to the
inner portions of your tire without being visible
on the outside. While driving, if you experience
a sudden vibration or ride disturbance, or if you
suspect that damage to your tires or vehicle has
occurred, immediately reduce your speed or stop.
Drive with caution or have your vehicle towed to
the nearest vehicle or tire dealer to have your
vehicle inspected.
WARNING!
Tire
changing can be dangerous and should be done by
trained personnel using proper tools and procedures.
Always read and understand any manufacturer's warning
contained in their customer's literature or molded
into the tire sidewall.
Failure
to comply with these procedures may result in faulty
positioning of the tire and/or rim parts, and cause
the assembly to burst with explosive force, sufficient
to cause serious physical injury or death. Never
mount or use damaged tires or rims.
WARNING!
Excessive
speed in a free-running, unloaded tire can cause
it to "explode" from extreme centrifugal force.
The energy released by such an explosion is sufficient
to cause serious physical injury or death.
Tire
Repairs -
When
a tire is losing air it must be removed from the
wheel by an expert for complete internal inspection
to be sure it is not damaged. Tires driven even
short distances while severely under inflated may
be damaged beyond repair.
Punctures
up to 1/4" in diameter, when confined to the tread,
may be repaired by trained personnel. These tires
must be removed from the wheel, inspected and repaired
using industry-approved methods which call for an
inside repair unit and a plug. Some punctures may
make the tire non-repairable. A plug by itself is
an unacceptable puncture repair.
The
repair material used -- for example, a "combination
patch and plug" repair -- must seal the inner liner
and fill the injury to be considered a permanent
repair. Never use a tube in a tubeless tire as a
substitute for a proper repair.
Individual
tire manufacturers may differ on whether the speed
category applies to speed-rated tires that have
been repaired. Consult the tire manufacturer's policy.
Aerosol
Inflators -
Do
not depend on tire aerosol sealants and inflators
to permanently fix a damaged tire. These products
are designed to provide only a temporary, emergency
repair to help get you off the road and to the nearest
tire repair facility. They may also make the tire
non-repairable.
Some
aerosol products of this type use flammable gases,
such as butane, propane or isobutane as propellants.
Follow all directions and precautions printed on
the canister when using these products. Be sure
to inform tire service personnel when you have used
any flammable aerosol to inflate your tire.
The
purpose of regularly rotating tires is to prolong
their useful tire life by achieving more uniform
wear for all tires on a vehicle. Before rotating
tires, check your owner's manual for rotation recommendations
for specific vehicles. If no rotation period is
specified, rotate your tires every 6,000 to 8,000
miles or at any sign of uneven wear. If the tires
show uneven wear, ask a serviceperson to check for
and correct any misalignment, imbalance, or other
mechanical problem before rotation.
Rotating
the tires as recommended by the RV or tire manufacturer
will help even out the amount of wear on each tire
and extend the life of the entire set.
Note:
Some kinds of tires cannot be rotated in the manners
described below. Such tires include uni-directional
tires and tires with asymmetric tread designs. Also,
some vehicles may have different-sized tires mounted
on the front and rear axles, and these different-sized
tires have rotation restrictions. Check your owner's
manual, or with your tire dealer, for the proper
rotation recommendations for these special cases.
When
tires are rotated, the inflation pressures must
be adjusted for the tire's new positions in accordance
with the actual loads on that wheel position. Under
inflated or over inflated tires may result in poor
handling, uneven tread wear and increased fuel consumption.
Note:
Lug nuts should be properly torqued anytime a tire/wheel/rim
assembly is re-installed on the vehicle.
Storing
RV -
When
recreational vehicles are out of service for long
periods of time, they should be put on blocks. Place
the blocks under the axles so that tires bear no
load during the storage period. Also ensure that
the tire/wheel assemblies are protected from direct
sunlight. Because inflation pressure will fluctuate
with surrounding temperatures, a slight, gradual
air loss will typically occur over extended periods.
Be sure to inflate the tires, including the spare,
to operating pressure before returning to service.
Tire
Storage -
If
you remove your tires from the RV, store them in
an area that is clean, cool, dry, dark and well-ventilated
with circulating air. Tires should be stored so
that the tires at the bottom of a stack retain their
shape. Store tires whitewall-to-whitewall to avoid
staining. If outdoors, protect tires with an opaque
waterproof covering.
Tire
Dealer Assistance -
When
you have questions about tires, consult your tire
dealer. A dealer is the best source of general information
and professional service on tires. Have your dealer
inspect your tires periodically and otherwise assist
you in maximizing your tire investment. Dealers
have service manuals, wall charts and other industry
publications on tire load and inflation, tire repairs
and tire replacements. They can provide any replacement
tires your vehicle needs, balance your tires and
properly repair damaged tires which are repairable.
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