English units of torque are pound-inches or pound-feet; the SI unit is the Newton-meter. Notice that the torque units contain a distance and a force. To calculate the torque, you just multiply the force by the distance from the center. In the case of the lug nuts, if the wrench is a foot long, and you put 200 pounds of force on it, you are generating 200 pound-feet of torque. If you use a 2-foot wrench, you only need to put 100 pounds of force on it to generate the same torque.
Friday, May 6, 2005
What is torque?
Torque is a force that tends to rotate or turn things. For example, you generate a torque any time you apply a force using an impact wrench. Tightening the lug nuts on your wheels is a good example. When you use an impact wrench, you are applying force to the socket. This force creates a torque on the lug nut, which tends to turn the lug nut.