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Image Gallery: Trucks

Image Gallery: Trucks How can torque get you out of a jam when you're off-roading? See pictures of trucks.

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Why is torque important in off-roading?

You've probably heard the term "torque" used to describe the power of SUVs and trucks. Like horsepower, it's a force that's vital to the movement and performance of all vehicles -- but especially to the four-wheel drive vehicles used in off-roading.

Torque is a force that creates rotation. For example, when you're tightening the lug nuts on your wheels, you're providing torque when you rotate the nuts with a wrench. Similarly, your vehicle's engine applies torque to the axles so that your wheels will rotate. Horsepower, on the other hand, is energy that pushes a vehicle in the same direction as the applied force.

Both horsepower and torque influence acceleration. Horsepower affects acceleration at high speeds, whereas torque aids acceleration from a stopping point. Because of this, torque is known as low-end power. Since off-road driving isn't performed at the high speeds of highway driving, low-end power is crucial in pushing your vehicle through the many slow-downs and speed-ups you encounter at ditches, debris-ridden paths, bumpy terrain, and muddy or snowy roads.

Torque is measured in pound-inches or pound-feet, which means the applied force (pounds) is multiplied by distance from the center (inches or feet). So, for example, if the wrench you're using to tighten your lug nuts is two feet (0.61 meters) long and you apply 100 pounds (45.36 kilograms) of pressure to turn it, you're creating 200 pound-feet (27.67 kilogram-meters) of torque. A vehicle with a lot of torque has a significant amount of applied force to help propel it.

Torque force is distributed to your wheels by a transfer case (also known as a gearbox). The transfer case sits behind your vehicle's transmission and distributes torque to the axles through driveshafts. Most transfer cases have a gear reduction, known as 4-Low (or 4Lo), that can send more torque to your wheels. When it comes to your off-road vehicle, this increased torque will come in handy when you're navigating rough, hilly or uncertain terrain.

For lots more information on off-roading, see the links on the next page.

Lots More Information

Sources

  • 4 Wheel & Off-Road Magazine. "Off-Road Driving Basics--Wheeling 101." http://www.4wheeloffroad.com/techarticles/trail/131_0505_off_road_driving_basics/index.html. 12/03/09
  • 4x4ABC.com-4WD Basics "What is the difference between Four Wheel Drive (4WD) high range and low range?" http://www.4x4abc.com/4WD101/difference_4WD-low-high.html
  • General Motors. "Horses, foot-pounds and other power talk." http://www.gm.com:80/experience/education/9-12/technology/ice_horsepower.jsp
  • Off-Road.com "Torque and Horsepower." http://license.icopyright.net/user/viewFreeUse.act?fuid=NjA5OTgxNw%3D%3D