ROUTINE MAINTENANCE
Vehicle capacity weight—The rated cargo and luggage load plus 68 kilograms (150 lbs.) times the
vehicle’s designated seating capacity.
Vehicle maximum load on the tire—The load on an individual tire that is determined by distributing to
each axle its share of the maximum loaded vehicle weight and dividing by two.
Vehicle normal load on the tire—The load on an individual tire that is determined by distributing to
each axle its share of the curb weight, accessory weight, and normal occupant weight (distributed in
accordance with Table I of CFR 49 571.110) and dividing by 2.
Weather side—The surface area of the rim not covered by the inflated tire.
Wheel center member—In the case of a non-pneumatic tire assembly incorporating a wheel, a
mechanical device which attached, either integrally or separably, to the non-pneumatic rim and provides
the connection between the non-pneumatic rim and the vehicle; or, in the case of a non-pneumatic tire
assembly not incorporating a wheel, a mechanical device which attaches, either integrally or separably,
to the non-pneumatic tire and provides the connection between tire and the vehicle.
TIRE PRESSURE
Correct tire inflation pressure is essential to maximizing the life of the tires and assuring the safety of the
vehicle and its occupants. Driving with tires that are not correctly inflated for the load of the motorhome
is dangerous and might cause premature wear, tire damage, and/or loss of control of the motorhome.
An underinflated tire will build up excessive heat that might actually approach the vulcanization
temperature of the rubber and lead to tread separation and/or disintegration of the tire.
Underinflated tires will also cause poor handling of the motorhome, rapid and/or irregular tire wear,
and an increase in rolling resistance of the motorhome, which, in turn, produces a decrease in fuel
economy of operation.
An overinflated tire will reduce the tire’s “footprint” (i.e., its actual contact with the road); thus, reducing
the traction, braking capacity, and handling of the motorhome. A tire that is over-inflated for the load
that it is carrying will also contribute to a harsh ride, uneven tire wear, and the tire itself will be more
susceptible to impact damage.
Maintaining correct tire pressure for each loaded wheel position on the motorhome is critically
important and must be a part of regular vehicle maintenance.
Tire Maximum Load Rating
Federal law requires that the maximum load rating be moulded into the sidewall of the tire. If you look
at a tire sidewall, you might see some “typical” information, such as:
Max. Load Single 3640 Lbs at 85-psi cold
Max. Load Dual 3415 Lbs at 85-psi cold
The maximum load allowed for the size of the tire and load rating and the minimum cold air-inflation
pressure needed to carry that stated maximum load are noted on the tire. Using less air pressure would
reduce the load-carrying capacity of the tire.
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