All four tires and wheels shall be interchangeable. Tires shall be
Wheels and tires.
pneumatic and conform to Federal Specification ZZ-T-381. When required, tires shall be equipped with
tubes in accordance with Federal Specification 22-1-550. The tires shall be of the size and ply dictated by
the performance in 3.2.1 and the tractor weight in accordance with the Tire and Rim Association
Sufficient clearance shall be provided for operation with tire chains when the
vehicle is loaded to maximum vehicle weight and the tires are inflated to recommended pressure. The
chains shall not strike the tractor parts. Installed chains of 5/8 inch deep cross links shall not contact any
part of the tractor in any steering mode at any speed (0-15 MPH) after 5 minutes of operation to allow
chains to expand. This applies to new or recapped tires of the same cross section as given in the Tire and
Rim Association Handbook. This shall be in accordance with SAE J683.
Fuel tank. The capacity of the fuel tank(s) shall ensure eight hours of normal operating duty.
The tank shall not project beneath the vehicle frame and shall be adequately protected from puncture
and/or structural damage. It shall be equipped with a filler tube, a safety filler cap, a float type rheostat or
fuel gauge indicator, a check valve in the fuel takeoff line, a fuel shutoff cock with the fuel line
connection, a drain plug at the lowest point in the tank bottom and an overflow which shall not carry fuel
onto the engine muffler, or exhaust tailpipe.
At least one primary filter/strainer of the fuel water separator type shall be
located in the fuel line between the fuel tank and the fuel pump. At least one secondary filter for filtering
fine dirt particles shall be located on the pressure (outlet) side of the fuel pump. All fuel filters shall be
installed so that the elements can be readily serviced without disturbing other items. If located below the
fuel tank level, a shutoff valve shall be provided between it and the tank so that the element maybe
changed without draining the tank.
Cab. The body design maybe either conventional (engine in front), cab over engine, or
forward control within the maximum dimensions given in 3.12. All horizontal top surfaces, including
the engine cover, but excluding the cab roof, shall be capable of supporting a 200 pound man at any one foot
square on the surface without permanent deformation. The cab roof shall be capable of supporting a 100
pound force at any one foot square on the surface. All normal foot traffic areas shall be skid resistant.
The cab shall be provided with access panels in its floor for any top adjusted or serviced components
located under the cab. All openings in the cab floor shall be sealed by boots or mats except for moisture
drain holes. The cab shall conform to the requirements of MIL-STD-1472.
The cab shall provide two identical seats for the tractor operator and passenger, The
seats shall conform in SAE J899 and MIL-STD-1472. The seats shall adjust fore, aft and vertically to
accommodate an operator as large as a 95 percentile male and as small as a five percentile female in
accordance with SAE J833, A full width bench seat meeting these requirements is acceptable. Seat lap
belts with retractors shall be provided for both operator and passenger. Belts shall be metal to metal
open position when exposed to 50 MPH winds from any direction.
3.4.3 Windshield and windows.
The cab shall be provided with a glare proof windshield of safety plate or
tempered safety glass. Two windshield wipers shall be provided. The wiper motor shall have a
minimum of two speeds.
18.104.22.168 Windows. The cab shall be provided with two doors with crank regulated windows and a rear
sliding window with two sliding sections.