Effective torque
Effective Torque is often referred to as wheel torque or torque to the wheels is primarily associated with automotive tuning. Torque can be measured using a dynamometer. Common units used in automotive applications can include ft·lbf and N·m. For more on units see: Foot-pound force.
The formula for effective torque to the wheels is:
Tw = Te * Ntf * ηtf
Ntf = Nt * Nf
ηtf = ηt * ηf
... where Tw is wheel torque, Te is engine torque, N is the gear ratio, η is the efficiency, and the subscripts t and f are for the gearbox and differential, respectively. Effective torque will often be 5-15% lower than the shaft or crank ratings of an engine due to a loss through the drivetrain.
For a general article please see: Machine torque.
