On
the Beach
Where possible, stay in high-range four wheel drive to maintain speed,
but if you bog down, go into low range and try again.
Your driving
depends on the sand conditions. Driving on hard packed sand can be very
straightforward, but more often, beaches are windblown, with soft, traction
sapping sand. This requires continual momentum, full throttle and partially
deflated tyres. (Absolute minimum pressure 1.1 bar or 16 psi).
Dropping
pressure elongates the tyre's contact patch, creating better flotation
through a wider footprint. Re-inflate the tyre as soon as possible after
leaving the beach. Prior to this, drive at a maximum of 80km/h.
Mudplugging
The most common 'mud negotiation' confronted by four wheel drivers is
a boghole on a bush track - usually furrowed by massive wheelruts and
axle-deep pits. Where possible, place the tyres on high ground to avoid
dragging the diffs through the mud. If you slip off, keep the accelerator
down and turn the steering wheel from side to side, enabling the side
lugs of the tyres to gain grip on the side face of the ruts.
Check for
buildup in the wheel arches. Clogged guards effectively eliminate any
tread pattern on the tyres, so it is advisable to clean them out with
a shovel where necessary.
Getting
through mud requires momentum, so as a general rule, high range and full
throttle is recommended.
Water
Water crossings terrify novice four wheel drivers more than any other
cross country circumstance.
The technique
is simple. As with any unfamiliar crossing, walk the course first, taking
note of any possible obstacles, and if necessary, marking their position.
Select low range, and generally first gear. (It is not advisable with
most 4WDs to change gear midstream, as water can get into the clutch plate).
After checking
that your air intake is high enough to remain clear of water in the deepest
section, set off, maintaining a steady speed to create a bow wave in front
of the vehicle.
Because
you can't see what the tyres are striking under the water, never reduce
air pressure, and for the same reason, check for sidewall slashes or puncturing
stakes after you've reached the other side.
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Over
Snow
The advantage of a 4WD in snow is that chains don't have to be fitted
immediately. In light snow conditions, the idea is to break through the
crust so the tyre tread can grip on the surface beneath. Select high
range and avoid acceleration surges and sudden breaking. In deeper snow
don't rev the engine, but go into low range and use minimal pressure to
let the tyres bite rather than slip.
Never wrench
the steering wheel sharply in snow - it could put you into a spin or a
skid.
Not even
the most capable 4WD, regardless of the tyres it's fitted with, can go
through endless depths of deep snow without chains.
Outback
The most notorious challenge in the outback is bulldust. First instinct
is to treat bulldust as if it were sand, but that can be a fatal mistake.
Never deflate your tyres, for beneath the deep, powder-fine stretches
of sand lies a rock hard base that pounds the chassis on impact and could
split the sidewall of a partially inflated tyre.
Select high
range and maintain a constant speed between 60 and 80km/h, correcting
any sideways slews with both the steering wheel and more throttle.
Rock Climbing
The skill in tackling rocky conditions is to keep the tyres on the high
ground all the time. This avoids 'high centering' (hanging the vehicle
up on diffs, the transmission or bashplates).
Torque is
more important than power in climbing rocky slopes, so select first or
second gear low range to east the vehicle over any obstacles. Use minimal
throttle openings to prevent tyre slip.
Where possible,
stick to roadgoing tyre pressures, only dropping them when the vehicle
is stuck and all other recovery techniques have failed. Although lower
pressures maximise tyre footprint, they also increase the danger of pinching
the tyre in a narrow crevice or slashing the sidewall on tree stakes or
rocks.
In
the Desert
While most of the techniques used in beach driving are applicable to desert
treks, a fundamental different exists. With localised exceptions, Australia's
deserts don't consist purely of sand but are a mix of sandridges interspersed
with rocky depressions and flat spinifex or mulga country, meaning that
tyres can very rarely be let down to coastal sand pressures for fear of
staking. Maintaining momentum is crucial.
Don't fight
the steering wheel. Rather, let the vehicle - within reason of course
- find its own way, but take care on crests. If you find yourself running
across the face of a dangerous slope, turn the wheels downhill and accelerate.
This not only stops the vehicle from rolling over, but also restores steering
capability and traction to the tyres. |