Rock crawling is an extreme form of off road driving using vehicles anywhere from stock to highly modified to overcome obstacles.
The vehicles
In order to successfully rock crawl, a capable vehicle is required. Most commonly a brand name truck or four wheeled vehicle will be outfitted with custom parts. Power is usually not an issue since low gears are common. These custom parts can include:
-
locking differentials
-
taller off road tires
-
upgraded suspension
-
four wheel steering
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roll cage for driver protection
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engine modifications for increased performance, mostly torque
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lowered gearing in either or all of the transmission, transfercase, or axle differentials
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winches
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body armor (rocker panels, fenders, etc.)
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bead locks (locks tires to the rims for low tire pressures)
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long travel shock absorbers, drop shackles, spring over conversions (to increase wheel travel)
Oversized, low-pressure, knobby mud-terrain tires are frequently used for this reason also. Likewise, most vehicles have a low-geared transfer case to make the most torque in the low speeds used for rock crawling. Suspension-wise, rock crawling vehicles sometimes have after-market lift-kits installed, raising the chassis and increasing suspension flex, though the rockcrawlers running the tougher trails often have fabricated suspension systems, or cobbled together leaf packs to cheaply achieve the goals, making it easier to drive over larger obstacles with less risk of damage to the vehicle. Most suspensions are made to be highly flexible, allowing for the maximum amount of tire area to contact the ground in any adverse situation found, while keeping the vehicle as low as possible for center of gravity considerations. Due to the conflicting nature of the dynamics and needs of rock-crawling and highway-driving vehicles, it is not unusual to modify a vehicle solely for offroad recreational usage.
Once a vehicle is deemed
"offroad only" ie. not
driven on the street and
trailered to trails or OHV
parks (Off-Highway Vehicle),
then the limits are sky
high.
On the extreme side, those
with more financial
resources can build their
own rock crawler to suit
their needs. There are many
benefits to this method. The
biggest is that the owner
has complete control over
what their vehicle is
capable of. Each part of the
vehicle can be custom
designed to specifically
suit their needs. In this
way a vehicle can be
optimized to only have the
parts that are required.
Also, they do not have to be
limited by the vehicles
exterior and can design
anything they want with no
restrictions. The downside
is that doing this is a much
larger investment of both
finances and time. Acquiring
sponsors can help to cover
some of these costs.
The terrain
The terrain used for rock crawling can vary just as much as the vehicles. Most commonly, rock crawling will occur where there are plenty of rocks, but any other steep or abnormal surface will do. Other obstacles may include mud, sand, water, and large hills. Preferably one should have enough good terrain to make a path with plenty of variation among the obstacles. The more difficult the path the better, but one must also take into account safety and the likelihood that they might not be able to make it. While a challenge is good, it is not good to blindly take on any challenge even if it means impending damage. Also going in a convoy of vehicles is advised as recovery when stuck is near impossible with a lone vehicle.
http://en.wikipedia.org/wiki/Rock_crawling