Chapter 5. HIGHWAY TRANSPORTABILITY GUIDANCE

TM 55-3805-248-14

CHAPTER 5

HIGHWAY TRANSPORTABILITY GUIDANCE

Section I. GENERAL

CAUTION

5-1. Scope.

The tires of the tractor-scraper are not

This chapter provides highway transportability

capable of withstanding excessive heat

guidance for the movement of the tractor-scraper,

generated by extensive highway travel.

wheeled, M621B. It covers significant technical

This excessive heat can cause sudden tire

and physical characteristics, as well as safety

failure. To drive an empty tractor-scraper

concerns, and prescribes the materials and guid-

for more than 20 highway miles, the

ance required to prepare, load, tie down, and

front axle tires must be inflated to 55 psi

unload the vehicle.

and the rear axle tires deflated to 25 psi.

Maximum highway speed should be lim-

5-2. Safety.

ited to 20 mph. After 2 hours of sus-

In addition to the safety precautions contained in

tained highway travel, the vehicle should

chapter 3, movement is subject to all safety laws,

stop for 30 minutes for a cooling period.

rules, and regulations applicable to commercial

After the second stop, or 4 hours total

carriers. Overseas, such movements are governed

highway travel, the vehicle should stop

by theater regulations. Vehicle transmission must

for a l-hour cooling period. For every 2

be placed in the neutral position and the park

stops or every 4 hours of highway travel,

brake on (air removed).

the cycle should be repeated. For all

CAUTION

other highway operations that do not

Vehicle speed must not exceed 3 mph

meet the conditions described in this

during loading or unloading.

caution, the Goodyear Off-the-Road De-

5-3. General.

partment, telephone (216) 796-2010,

Akron, Ohio should be contacted.

The vehicle is considered self-deliverable only

Movement over public highways will not be at-

under appropriate tactical conditions. The tractor-

tempted without specific approval. The 136-inch

scraper, M621B, when empty, has a maximum

width exceeds limitations in CONUS and over-

range of 176 miles (283 km) and a maximum

speed of 31 miles per hour (50 km/h).

seas.

Section Il. TRANSPORT BY SEMITRAILER

5-4. Transport of Tractor-Scraper,

of the ROPS/FOPS cab only lowers the height 9

inches and lessens the weight 1,000 pounds.

M621B by Semitrailer.

5-6. Transport of Tractor-Scraper,

When loaded on semitrailers, the tractor-scraper

can be transported over highways; however,

M621B on M870 Semitrailer Towed by

movement over public highways in CONUS and

M920 Truck Tractor.

overseas should be made only when other trans-

a. General. The combined length of the tractor

port modes cannot be used. When highway ship-

and semitrailer (65 feet) exceeds the generally

ments must be made, this vehicle should be

accepted CONUS and overseas standards. The

loaded onto military or commercial low-bed

height (195 inches or 16 feet, 3 inches) severely

semitrailers of adequate capacity. In addition to

limits bridge clearance. Additionally, the width,

the limitations and restrictions identified in para-

tandem axle loads, and gross vehicle weight

graph 5-3, the height and weight limitations in

exceed highway limits in most countries. Where

CONUS and overseas are exceeded when the

limits are exceeded, special permits and special

tractor-scraper is loaded on a semitrailer.

routing are required.

b. Materials. The bill of materials for blocking

5-5. Preparation

of Tractor-Scraper.

and tiedown of the tractor-scraper on the M870

The vehicle will not be reduced, because removal

semitrailer is shown in table 5-1.

5-1