Lesson 1/ Learning Event 1
You will commonly hear a vehicle referred to as a four-by-four (4x4), a six-by-six (6x6), or even a
four-by-two (4x2). This means that, if a vehicle has four wheels and only the front or rear wheels
are powered, it is called a 4x2. If all four wheels can be powered, it is a 4x4. If the vehicle has
four wheels in back and two in front, it will be either a 6x4 or 6x6, depending on how many
wheels can receive power.
All-wheel drive vehicles are needed in the Army because Army vehicles must travel cross-country in
snow, mud, and sand as well as on hard-surfaced roads.
Angle of approach
To understand "angle of approach," just think of driving on level ground and then coming to a
steep upgrade. If the grade is too steep, the vehicle bumper will strike the ground. When we say
angle of approach, we mean the steepest grade angle that a vehicle can come up to and start to
climb with no part of the vehicle scraping or digging into the ground.
Angle of departure
"Angle of departure" is the opposite of the angle of approach.
It is the steepest downgrade a vehicle can leave with no part of the vehicle except the wheels
touching the ground.
This term refers to the distance a vehicle can travel on a full tank of fuel under normal conditions.
This is important because, as you know, military vehicles cannot always stop at roadside gas
stations. Therefore, you need to know how far the vehicle can travel on a full tank so that you can
carry extra fuel if you are going to need it to complete a trip.
Most military vehicles have a device attached to the rear of the frame to connect a trailer for
towing. This device is called a pintle, and it is merely a hinged connection that can be opened for
hooking up the trailer and then can be closed in a locked position.
"Drawbar pull" is the amount of trailer load that can be safely handled by the vehicle and trailer