Heartland 2014 Bighorn, Owner'S Manual

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37 Home is where your heart is...
U.S. DOT Tire Identification Number
This begins with the letters “DOT” and indicates that the
tire meets all federal standards. The next two numbers or
letters are the plant code where it was manufactured, and
the last four numbers represent the week and year the tire
was built. For example, the numbers 3197 means the 31st
week of 1997. The other numbers are marketing codes
used at the manufacturer’s discretion. This information is
used to contact consumers if a tire defect requires a recall.
Tire Ply Composition and Materials Used
The number of plies indicates the number of layers of
rubber-coated fabric in the tire. In general, the greater the
number of plies, the more weight a tire can support. Tire
manufacturers also must indicate the materials in the tire,
which include steel, nylon, polyester, and others.
Maximum Load Rating
This number indicates the maximum load in kilograms
and pounds that can be carried by the tire.
Maximum Permissible Inflation Pressure
This number is the greatest amount of air pressure
that should ever be put in the tire under normal driving
conditions.
Vehicle Load Limits
Determining the load limits of a vehicle includes more
than understanding the load limits of the tires alone. A
Federal Certification Label is located on the forward half
of the left (road) side of the unit. The certification label will
indicate the vehicle’s gross vehicle weight rating (GVWR).
This is the most the fully loaded vehicle can weigh. It also
provides the gross axle weight rating (GAWR). This is the
maximum weight a particular axle can carry. If there are
multiple axles, the GAWR of each axle will be provided.
In the same location as the certification label described
above, there is a vehicle placard. This placard provides
tire and loading information. In addition, this placard will
show a statement regarding maximum cargo capacity.
Cargo Capacities
Cargo can be added to the vehicle, up to the maximum
weight specified on the placard. The combined weight of
the trailer and cargo is provided as a single number. In
any case, remember: The total weight of a fully loaded
vehicle can not exceed the stated GVWR.
Water and propane also need to be considered. The
weight of fully filled propane containers is considered
part of the weight of the RV before it is loaded with cargo
and is not considered part of the disposable cargo load.
Water however, is a cargo weight and is treated as such.
If there is a fresh water storage tank of 100 gallons, this
tank when filled would weigh about 800 pounds. If more
cargo is being transported, water can be off-loaded to
keep the total amount of cargo added to the vehicle
within the limits of the GVWR so as not to overload the
vehicle.
Understanding this flexibility will allow you, the owner,
to make choices that fit your travel and camping needs.
When loading your cargo, be sure it is distributed evenly
to prevent overloading front to back and side to side.
Heavy items should be placed low and as close to the
axle positions as reasonable. Too many items on one
side may overload a tire. The best way to know the actual
weight of the vehicle is to weigh it at a public scale. Talk to
your RV dealer to discuss the weighing methods needed
to capture the various weights related to the RV. This
would include weights for the following: axles, wheels,
hitch or pin (in the case of a trailer) and total weight.
How Overloading Affects Your RV and Tires
The results of overloading can have serious
consequences for passenger safety. Too much weight
on 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 tire, its load range, and
corresponding inflation pressure. Excessive loads and/
or under-inflation cause tire overloading and, as a result,
abnormal tire flexing occurs. This situation can generate
an excessive amount of heat within the tire. Excessive
heat may lead to tire failure. It is the air pressure that
enables a tire to support the load, so proper inflation is
critical. Since RVs can be configured and loaded in many
ways, air pressures must be determined from 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, the
load will need to be lightened.