Hummer 2006 H3 - Manual (Page 223)

Design specifications required a minimum gradeability
of 60% (31 degrees) slope, with the vehicle fully loaded,
on high friction surfaces with maximum vehicle speed
not to exceed 6 mph (9.7 km/h). The vehicle is expected
to traverse this grade only for short durations. Never
stop and idle the vehicle or park it on this grade. Also, your vehicle should be able to traverse a
40% (22 degrees) side slope at 6 mph (9.7 km/h)
while fully loaded on high friction surfaces.
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