Operation and Stability
The rated capacity of a counterbalanced reach stacker applies only when the truck is on
level ground and the load is at the proper height and distance from the front wheels.
It is important that you understand this capacity is reduced and the truck is less stable
when:
● the boom is raised
● the boom is extended
● the truck is on an incline
Reach stacker stability is dependent on the truck’s three point suspension represented
by Figure 3.
The truck is supported on the drive axle tires (points A and B) and the centerline of the
steer axle pivot (point C).
Point D represents the location of the center of gravity of a truck without a load. Point F
represents the center of gravity of the load. Point E represents the combined center of
gravity of both the empty truck and the load. The combined center of gravity (point E)
must remain within the triangle formed by points A, B, and C. Stability depends on how
close point E comes to the edge of this triangle. If for any reason this point exceeds the
triangle’s boundary, the truck will tip.