TM 9-2610-200-14
2-12
EXCESSIVE TOE-OUT EXCESSIVE TOE-IN
CHAPTER 2. CARE, MAINTENANCE, AND INSPECTION (Con't)
SECTION I. GENERAL INFORMATION (Con't)
2-18. TIRE WEAR PATTERNS (Con't).
a. AIR PRESSURE (Con't)
(1) Underinflation. An underinflated tire
does not contain enough air for its size and the
load it must carry. It flexes excessively in all
directions and gets hot. In time, the heat
weakens the cords in the tire and may cause a
blowout. Underinflation also causes tread edges
to scuff the road, which puts uneven wear on
the tread and shortens tire life. Never run a flat
or nearly flat tire unless the tactical situation in
combat requires it. When run for even a short
distance or almost flat for long distances, the
tire may be ruined beyond repair.
(2) Overinflation. Overinflation also causes tire failure. Excessive pressure prevents the tire from
flexing enough and causes it to be constantly subjected to hard jolts. When an overinflated tire hits a stone
or rut, the cords may snap, causing a break in the cord body. The center of the tread wears more rapidly
and does not permit equal wear across the entire tread. Hard riding from too much air pressure also
increases wear.
(3) Deflation. Tires should never be deflated during or immediately after vehicle operation for
the purpose of air pressure adjustment. Tires heat as they roll, causing air to expand, which increases
pressure. When the tire cools after pressure adjustment it becomes dangerously underinflated. Pressure
increases of more than 20 psi (138 kPa) could indicate
underinflation, overloading, or excessive speed.
b. MISALIGNED WHEELS.
(1) Improper Camber Angle. An improperly
adjusted camber angle will cause tires to wear. Improper
camber angle means that the wheel assembly is leaning in
or out at the top. This causes the tread area to contact the
road harder on one side than on the other. causing that
side of the tread area to wear unevenly and rapidly.
(2) Excessive Toe-in. Excessive
toe-in will cause a tire tread to wear.
Feathered edges will develop in the inner
edges of the tread design. In extreme cases
the feathered edges may also appear on the
inner edge of the tread area.
(3) Excessive Toe-out. Excessive
toe- out will cause a tire tread to wear as
indicated. Feathered edges will develop on
the outer edges of the tread design. In
extreme cases the feathered edges may also
appear on the outer edges of the tread area.
UNDERINFLATION OVERINFLATION
