Hummer 2009 H2 - Manual (Page 310)

Roll The Tires Over Large Rocks
Do not straddle large rocks;
drive over them, letting the
tire cover the rock. The
tread of the tire is thicker
and tougher than the
sidewall of the tire and is
more resilient to impact
than underbody
components.
Log Crossing
Using the proper technique, the vehicle will cross logs
up to 10 inches (25.4 cm) in diameter. Approach the log
at approximately a 15° angle (A) with the transmission
in 1 (First) and the transfer case in 4LO LOCK and “walk”
the vehicle over, one tire at a time. It may be necessary to
modulate the brake pedal and accelerator to avoid
spin-out. Ease the vehicle down from the log with the
brake.
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