One of the most challenging forms of off-roading is rock crawling, or driving over rocks: small rocks, big rocks, boulders and even mountainsides. The activity requires precision, planning and prior knowledge of your vehicle.
The key to rock crawling is the speed at which you slowly pass over the rocks; thus, the "crawling." Some recommend crawling at no more than 3 miles per hour (4.8 kilometers per hour) [source: DeLong]. Unlike mudding, speeding over rocks can get you stuck or damage your car. With rock crawling, you have to maneuver your car precisely; you need to know exactly where your tires will fall at all times.
Off-roading involves a lot of picking your line, or planning out the path you are going to take before you start driving it. This level of forethought is especially important in rock crawling, since you need to make sure your path, or line, can be managed by your vehicle. Sometimes you might want to get out and walk the line first to get a better idea of the terrain. Some off-roaders also use a spotter, a person who stands nearby and guides the driver in getting over the rocks.
A lot can go wrong when you're rock crawling. First, rocks can be sharp and jagged. The sidewalls of your tires are the weakest part, so you need to be careful where they come into contact with rocks to avoid puncturing them. Second, if you're moving too fast, the side-to-side rocking motion of your car as the tires move over rocks can build up and cause your vehicle to tip.
Knowing the angles on your car is very important in rock crawling. For each rock you encounter, you have to be able to judge whether your vehicle can clear it. This is yet another reason why speed isn't on your side when rock crawling: If you go too fast, you might not be able to accurately judge the obstacles in front of you. You also want to avoid straddling large rocks because there's always a chance they could damage the underside of your vehicle. The best option is to take a rock on with your tires instead of trying to pass over it. In other words, line up your tires with the rock so you'll drive over it. Don't expect the middle of your car to be able to clear it.
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