TIRE MAINTENANCE MANUAL - Goodyear Off-The-Road (OTR)

forms a barrier to protect the carcass from
the weather.
Deflection
Many people think that deflection describes
the bulge at the bottom of a loaded
tire. Actually, this bulge occurs as a result of
deflection.
Deflection really describes the change in
the tire’s radius when a normal load is applied.
The radius is measured from the center
of the axle/hub to the ground (See
Figure 2, above).
Unloaded Radius is measured with no
weight on the tire. The tire is mounted on
a rim and inflated to working pressure. The
tire is stood and supported so the tread
touches the ground. However, no load is
applied (ie. not even the weight of the tire
and rim).
Basic Factors Tire Maintenance
UNDEFLECTED
(Zero Load)
NORMAL
DEFLECTION
(Rated Load/Inflation)
5
Inner Liner
A specially formulated rubber compound inside
the tire that minimizes permeation. It
works with the rim and O-ring to contain
the inflation medium in tubeless designs.
OVERDEFLECTION
(Overload and/or
Underinflation)
Static Loaded Radius is measured with the
weight of the vehicle and payload on the
tire. Static means that the tire is standing
still.
The deflection is the difference between
the Unloaded Radius and Static Loaded
Radius. This is the same distance that the
axle lowers when the vehicle is fully
loaded.
Deflection is extremely important. Engineers
design tires to operate at a certain percentage
of deflection. Operating with too
much deflection reduces tire life.
Load and Pressure Relationship
Each tire is designed to carry a specific load
at a specific inflation pressure. (Load/Inflation
Tables are in the back of this book).
When the tire is inflated to the correct