4 respecting compressed air a terrific force is

4. Respecting compressed air. A terrific force is contained in an inflated tire. An
explosion of the tire-and-wheel assembly can result from improper or careless
mounting procedures. Never stand over a tire while inflating it. If the tire explodes,
the sudden release of compressed air has enough energy to throw a person more
than 30 feet (9 m) in the air. People have been seriously injured or killed by
exploding tires.
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5. Protecting your eyes Wear eye protection (safety glasses, safety goggles, or a face
shield) when demounting and mounting tires. When deflating a tire, avoid the air
stream from the tire valve. The air comes out at high speed and can blow dirt or
debris into your eyes.
Checking Tire Pressure and Inflating Tires
Before checking tire pressure and adding air, know the correct pressure for the tire.
The specification is in the owners manual and on the vehicle tire-information label.
When the vehicle is carrying a heavy load, pulling a trailer, or driving at sustained
highway speed, higher tire pressure may be necessary. Maximum pressure should
never exceed the maximum pressure marked on the tire sidewall.
Inflation pressure is given for a cold tire. Pressure increases as tire temperature rises.
Highway driving on a hot day can increase the tire pressure from 5 to 7 psi (35 to 48
kPa). As the tire cools, it loses pressure. Never bleed a hot tire to reduce its pressure.
The pressure will then be low when the tire cools. Install the cap on the tire valve after
checking pressure or adding air.
Tire Inspection
The purpose of inspecting tires is to determine if they are safe for further use. When
defects or improper wear patterns are found, inform the driver. Recommend the
services that will correct the cause of the abnormal wear.
Tires have tread-wear indicators or wear bars. These are filled-in sections of the tread
grooves that will show when the tread has worn down to 1/16 inch (1.6 mm). A tire
with a wear bar showing is worn out and should be replaced. Too little tread remains
for continued safe driving. A tread-depth gauge can be inserted into the tread grooves
to measure tread depth of at least 1/32 inch (0.8 mm) in any two adjacent grooves at
any location on the tire.
Check for bulges in the sidewalls. Bulges mean plies have separated and the tire could
fail at any time. Tires with separated or broken plies should be replaced.
Date Performing Underchassis Preventive Maintenance Page no.

OPERATION SHEET No. 1(LO7)
Wheels and Tires
 Examine the sidewalls and tread area of each tire in turn. Check for cuts, tears,
and lumps, bulges, separation of the tread, and exposure of the ply or cord.
Check that the tire bead is correctly seated on the wheel rim, that the valve is
sound and properly seated, and that the wheel is not distorted or damaged.