Exmark Laser Z Propane Operator's Manual page 31

Operation
a surface for the frame members to contact if the
unit starts to tip backward. If it is not possible to use
one full width ramp, use enough individual ramps to
simulate a full width continuous ramp.
Ramp should be long enough so that the angles
between the ramp and the ground and the ramp and
the trailer or truck do not exceed 15°. A steeper angle
may cause mower deck components to get caught as
the unit moves from ramp to trailer or truck. Steeper
angles may also cause the unit to tip backward. If
loading on or near a slope, position the trailer or
truck so it is on the down side of the slope and the
ramp extends up the slope. This will minimize the
ramp angle. The trailer or truck should be as level
as possible.
Important: Do Not attempt to turn the unit
while on the ramp, you may lose control and
drive off the side.
Avoid sudden acceleration when driving up a ramp
and sudden deceleration when backing down a ramp.
Both maneuvers can cause the unit to tip backward.
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