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How Off-road Vehicles Work


Off-road Lights
Auxiliary lights can brighten your off-road adventures.
Auxiliary lights can brighten your off-road adventures.

When night falls in the wilderness, far from the array of lamps lining city streets and interstates, you'll welcome the glow of your vehicle's lights. Most 4x4 vehicles roll off the factory floor with some off-road lighting. For example, fog lamps -- high-efficiency round lamps capable of producing a low, wide beam -- come standard on many trucks and SUVs. ATVs sport headlights, as well, with some featuring a tri-beam system that allows the driver to run the low beams, the low and upper high beams together or turn them all off.

Most off-road drivers choose to supplement their vehicle's factory lights with auxiliary lights. If you do, here are some things to consider:

  • Round vs. rectangular. Off-road lights come in round or rectangular designs and sizes. Round lights range between 5 and 9 inches (13 and 23 centimeters) in diameter, while rectangular lights typically come 5 by 7 inches or 6 by 9 inches (13 by 18 centimeters or 15 by 23 centimeters, respectively). Many off-road drivers outfit their vehicles with both round and rectangular lights.
  • Housing construction. Off-road lights must be durable enough to withstand abuse. Look for a sturdy housing and a shatterproof polycarbonate lens. Some manufacturers offer mesh covers to help protect the lamp.
  • Lighting efficiency. There are two things to consider here: the shape of the lens and the bulb technology. Many off-road enthusiasts prefer round lights because they feature parabolic lenses with the filament located at the focal point. This design throws a more efficient light pattern than a lens with a square or rectangular shape. Xenon bulbs also increase light efficiency over halogen bulbs. A xenon bulb provides more light, but consumes far less power. Not only that, the light it produces is whiter and more similar to sunlight (see sidebar).
  • Beam patterns. Many lamps are available in fog or driving designs, a designation indicating the kind of beam produced by the lamp. Fog lights throw a low, wide beam that doesn't extend very far in front of the vehicle. Driving lights send a narrower beam a much greater distance. Some lamps produce a "pencil" beam, a long stream of light with a range of 2,500 feet (762 meters). And still others can have their beam pattern adjusted.

Of course, selecting off-road lights is just the beginning. You also have to mount them. Light kits, which typically come with lamps, wiring harness, relay and switch, can make installing lights much easier. Lastly, a light bar, mounted to the bumper or roof, can provide the extra surface you need to hold all of your auxiliary lights.


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