DRIVING & SAFETY — 2
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20 08 CONTESSA
If not properly supported, the steel cables in
the sidewall of the tires may be damaged and
could lead to premature fatigue of the sidewall.
CAUTION:
Supporting the tires prevents damage
to the sidewall of the tires but does not
prevent tire roll.
Tire Vibration
Sudden tire failure is often preceded by tire
vibration. Symptoms that can cause tire failure
are a bulge in the sidewall or swelling in the
tire carcass. Striking an object or large hole
in the road surface can damage a tire. Inspect
the tires periodically thereafter as rotational
forces can continue to stress damaged areas
and later manifest in tire failure. If an unusual
vibration begins, or a bulge is noticed in the
sidewall, have the tires evaluated by a qualied
professional as soon as possible.
Tire Rotation
Tire rotation can increase the useful life of the
tires by achieving uniform wear on all of the
tires. Have the tire manufacturer determine the
rotation pattern. The rst tire rotation is the most
important in determining which rotation pattern
to use. Any unusual or unique wear patterns,
or indications of uneven wear that may have
developed, should be evaluated for possible
tire rotation. Misalignment, imbalance or other
mechanical problems may exist and will need to
be corrected prior to rotation.
Tire Replacement
As represented within the tire manufacturer’s
published tire data guide, the size and rated
load carrying capacity of the original equipment
tires on your motorhome meet or exceed the
motorhome’s maximum axle weight/load
ratings.
Criteria that is used in determining when its
time to replace tires is road hazard damage,
wear and age. Tire replacement based on wear
is determined by either measuring depth of the
groove of the tire or by “wear bars.” Tires are
considered worn out and in need of replacement
when the depth of the groove is 2/32” or less on
rear tires, or 4/32” or less on front tires. Wear
bars are raised areas cast into the groove of the
tire. The tire is considered worn out and needs
replaced when the wear bar in the groove is
even (preferably before) with the road surface
contact patch. A worn out tire cannot adequately
channel water through the groove, resulting in
hydroplane.
Tire replacement based on age is determined
by the tire manufacturer. While ozone inhibitors
in the rubber help extend the life expectancy of
a tire, exposure to the elements slowly break
down the rubber, which can then suddenly fail
when put to use. Tires that are 5-7 years old
(depending upon environment) are considered
age worn and need to be replaced for safety
even when the tire does not outwardly show age
weathering and still has considerable tread.
Replacement tires must be of the same
manufacturer brand/make and model, size, and
load range at each wheel position (matched set)
and must have a load rated carrying capacity
equal to or greater than the original equipment
tires. Mixing tires of a different brand, model,
size, load rating and load range can cause
unusual handling and uneven braking due to
different traction coefcient and could result
in sudden tire failure or loss of control due to
non-symmetrical handling.
WARNING:
Never mix tires of different sizes, load
ranges or manufacturer brand types
or models. Any and all replacement
tires must have a rated load carrying
capacity equal to or greater than
the gross axle weight/load ratings as
identified by the federal placard.
WARNING:
In many instances tire life is not
determined by mileage or wear but by
age. Tires are subject to weathering.
Weathering cracks can appear in the
sidewall and also run along the edge
of the tire. Though the sidewall of
the tire may look structurally sound,
weathering can occur inside the groove
of the tread. If any tire exhibits age
weathering, replace all tires.
CAUTION:
Signs of irregular tread wear, exhibited
by scalloping or unusually smooth
areas on the tire surface, are cause for
concern. Immediately have the tire
manufacturer inspect the tires.
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