Torque is the twisting force applied to a shaft. The metric system uses the Newton meter (Nm). The Imperial system uses the inch-pound (in-lb) and the foot-pound (ft-lb). Vehicle manufacturers specify torque settings for key fasteners on the engine and wheels. You’ll need to follow the specifications or you could strip threads or break bolts. Torque is also an important concept when discussing engine performance.
Torque definitions
Torque conversions
Source: CDX Global