Snorkel SR3084SL - Manual (Page 41)

Chapter 8 – Operation
SR3084SL – 8210037 37
Some of the factors taken into consideration when cal-
culating theoretical gradeability include:
Drive motor effi ciency
Machine weight
Machine center of gravity
Tire traction
Tire contact
Condition of slope
The value for theoretical gradeability will most always be
high when compared to the actual gradeability value. The
perception then is that the machine can climb a steeper
slope than is actually practical.
Actual Gradeability
Actual machine gradeability refers to the maximum slope
that the machine is capable of travel under practical condi-
tions. It, too, is based on mathematical calculation, but it
also takes into account the practical application.
At any given moment when driving the machine on a
slope, at least one, if not all, of the factors contributing
to achieving theoretical gradeabilty will not be at optimal
performance. For example, tire contact may not be the
same at each drive wheel or the slope conditions may not
be optimal, which would then allow for loss of traction.
y
y
y
y
y
y
The value for actual gradeability will always be lower
than the theoretical gradeability value. The perception
then is that the machine can not climb a slope as steep
as it should.
Percent vs. Degree of Slope
Gradeability is most often referenced as a percentage.
That value is based on a slope angle of 45° representing
100% grade.
Angle indicators, or inclinometers, often measure the
angle of the slope in degrees not the percent slope.
Because of that, it may be useful to understand the re-
lationship between percent slope and the degree of the
slope angle as shown in Figure 8.5.
Driving on a Slope
The machine should only be driven on a slope or load-
ing ramp in the stowed position with the platform on the
downhill side.
A
Danger
The aerial platform can tip over if it becomes unstable.
Death or serious injury will result from a tip-over ac-
cident. Do not drive on slopes that exceed 35 percent
grade, or where conditions of the slope could cause
driving to be hazardous.
Percent of
Grade
Angle of Slope
in Degrees
45°
40°
30°
35°
25°
20°
15°
10°
5°
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
55%
60%
65%
70%
75%
80%
85%
90%
95%
100%
0
Figure 8.5 – Slope Percent/Degree Conversion