figure 7-14. First, R or TR followed by a number
NOTE: Rebuilt tires may NOT have the vent holes
identifies the number of times the tire has been rebuilt.
Next, the Julian date of the tire's rebuilding is added.
Finally, the name of the rebuilder and plant location is
The life of a tire, whether mounted or unmounted,
is directly affected by storage conditions. Tires should
always be stored indoors in a dark, cool, dry room. It is
Tube tires with inflation pressures greater than 100
necessary to protect them from light, especially
psi and all tubeless tires must be suitably vented to
sunlight. Light causes ultraviolet (UV) damage by
relieve trapped air. Tube tires are vented in one of two
breaking down the rubber compounds. The elements,
ways. The first method uses air bleed ridges on the
such as wind, rain, and temperature changes, also break
inside tire surface and grooves on the bead faces. The
down the rubber compounds. Damage from the
ridges and grooves channel the air trapped between the
elements is visible in the form of surface cracking or
inner tube and the tire to the outside. The second
weather checking. UV damage may not be visible.
method uses four or more vent holes that extend
Tires can be protected from light by painting the
completely through each tire sidewall. They relieve
storeroom windows. Tires must not be allowed to come
both pocketed air and air that accumulates in the cord
in contact with oils, greases, solvents, or other
body by normal diffusion through the inner tube and
petroleum products that cause rubber to soften or
tire. Tube tire vent holes are marked with an aluminum-
deteriorate. The storeroom should not contain
or white-colored dot.
fluorescent lights or sparking electrical equipment that
could produce ozone.
Tubeless tires have vent holes that penetrate from
the outside of the tire sidewall to the outer plies of the
Tires should be stored vertically in racks and
cord body. They relieve air that accumulates in the cord
according to size. See figure 7-15. The edges of the
body by normal diffusion through the tubeless tire liner
racks must be smooth so the tire tread does not rest on a
and the tire carcass. Vent holes in tubeless tires are
sharp edge. Tires must never be stacked in horizontal
marked with a bright green dot.
piles. The issue of tires from the storeroom should be
Figure 7-14.--Rebuilt tire identification markings.