Moving on Sand - Dune Worlds: How Windblown Sand Shapes Planetary Landscapes - page 252

Fig. 22.8 A quad-bike making a steep descent on Sand Mountain, Nevada. Note the flag for safety, and the helmet. Photo Ralph Lorenz

20 % if three passengers get out—the reduction in loading
is even more significant for a small vehicle like a quadbike
(Fig. 22.9 ). The number of bystanders in Fig. 22.5 does not
necessarily indicate laziness, rather that reducing the load-
ing on the wheels will help get unstuck.
In soft sand, reducing the slope of the wheel pits may not
be enough, in that the sand may slip and the wheels spin
without providing any forward force. In this instance, one
needs to insert a surface that will allow the wheels to
develop some friction and therefore forward push;
depending on location, nearby grass or twigs may do the job
or, if pushed, one can improvise with clothing or cardboard.
Professionals, however, will have surfaces to hand specifi-
cally for the job: so-called 'sand channels' (Fig. 22.10 )or
'tracks' are typically long steel plates a couple of tire
diameters long and a bit more than a tire width wide, usu-
ally corrugated to provide stiffness and perforated to reduce
weight and to improve grip. These can be inserted in front
of and under the tires (to form a ramp, and to provide a
nonslipping surface).

22.4 Getting Unstuck

If one involuntarily stops moving in a wheeled vehicle,
there is a chance one can recover without leaving the
vehicle. One should attempt—slowly—to reverse out along
the compacted tracks. If backing out fails, a number of
factors may be contributing to the situation; it pays to
understand them and to survey the underside of the vehicle
before taking further action. Avoid sudden changes in speed
or torque that may cause slip and the wheels to spin as this
will just make matters worse.
First, if wheel-spinning has occurred, the tires may have
dug themselves into pits. These present steeper local slopes
for the wheels to climb out of, that therefore require more
forward push. This barrier can most effectively be reduced
by digging ramps into the forward part of the holes,
although occasionally the short-cut of having helpers rock
the vehicle back and forth may get you out of the pits.
Indeed, whether they push or not, passengers should dis-
mount. A 1500 kg vehicle will have its load reduced by