TM-5-3805-254-14-P-2

TRUCK, DUMP, 20 TON, 6X4, ON-OFF HIGHWAY 71,000 GVW, IHC MODEL F-5070 (CCE)

TECHNICAL MANUAL; OPERATOR’S, ORGANIZATIONAL, DIRECT SUPPORT, GENERAL SUPPORT AND DEPT MAINTENANCE MANUAL (INCLUDING REPAIR PARTS INFORMATION AND SUPPLEMENTAL MAINTENANCE INSTRUCTIONS)

JUNE 1980

TM-5-3805-254-14-P-2 - Page 865 of 894

TRUCK SERVICE MANUAL

WHEELS, RIMS, TIRES

Overinflation is also costly because a tire which

is 20% overinflated will produce only 92% normal tire

mileage.

"Bleeding" of air from hot tires should never be

practiced. The pressure will be reduced but an increase

in temperature will result as soon as driving continues.

Fig. 11

Chart Showing Effects of Bleeding

The chart (Fig. 11) illustrates a condition where a

tire was started cool with a pressure of 70 pounds and at

a temperature of 26.7 degrees C (80 degrees F).

A

-

Initial conditions.

B

-

After 225 km (140 miles) of driving

the pressure had increased to 85

pounds and temperature 93.3 degrees

C (200 degrees F).

C

-

The pressure was then "bled" to 70

pounds and an additional drive made

of 225 km (140 miles). Note the temperature.

D

-

The pressure had increased to 73

pounds while the temperature increased

to approximately 104.4 degrees C (220

degrees F).

E

-

Again "bleeding" was resorted to.

Note the temperature.

F

-

After 322 km (200 miles), the tire

failed from a temperature of over

121.1 degrees C (250 degrees F).

LOADS

Loading tires beyond their rated capacity is

expensive because tire mileages are rapidly decreased

with overloads. The following chart (Fig. 12) illustrates

how an overload of only 20% will result in tire mileage

being only 70% of normal.

Fig. 12

Overload vs. Mileage

856