equipment is similar to those shown in figures 3-28 and
The first step in tire changing is to remove the valve
core and deflate the tire completely. When using any tire
repair equipment, install the tire and rim by closely
following the manufacturers instructions. The
pneumatic tire demounter holds the wheel and tire still
while it breaks the tire bead loose from the wheel rim.
An adapter is used to remove the tire from or replace it
on the rim. Tire demounters are manual, hydraulic, or
air-operated. The one shown in figure 3-28 is an
air-operated demounter for automotive and light truck
NOTE: All of the related instructions for the use of
tire shop equipment must be posted in the tire shop.
The spreader (fig. 3-29) separates the tire beads
enough to allow close inspection and maintenance on
the inside of the tire. When mounting a tire, inflate the
tube until it is almost round. Put the inside bead of the
tire on the rim and insert the tube into the tire with the
valve at the balance mark on the tire. Place the valve
stem through the hole and make sure that it is
perpendicular to the hole. This step prevents chafing and
damage to the valve stem during vehicle operation.
When installing the second bead on the rim, start on the
opposite side from the valve stem.
Place the tire and wheel in an APPROVED
SAFETY CAGE (fig. 3-30). After mounting it on the
rim, inflate the tire slowly. Make sure the tire beads fit
snugly against the rim flanges. You may have to over-
inflate the tire at first to make the bead seat on the rim.
Once seated, allow the tire to deflate and install a new
valve core. Then inflate the tire to the recommended
Unless your tire shop is well equipped, machinery
for repairing truck tires, such as split rims and rims with
removable side rings, may not be available or may not
work on the various types of wheels and rims you may
Figure 3-31.Locking ring rim.
have to repair. When repairing tires with locking rings
(fig. 3-31), first remove the valve core and deflate the
tire. Force the tire bead away from the removable side
ring with a slide hammer device intended for this
purpose. Next, remove the side ring, as shown in figure
3-32, views A and B. Turn the wheel and tire over and
Figure 3-32.-Demounting and mounting a military truck tire.