Effective torque

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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.[1] 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.


  1. ^ R. Ghafoori Ahangar, M. R. Meigounpoory, A. Eskandari. "Fuel Consumption and Gearbox Efficiency in the Fifth Gear Ratio of Roa Vehicle" (PDF). Adv. Theor. Appl. Mech., Vol. 3, 2010, no. 7, 299 - 308.