Torque Multipliers Information

Selecting torque multiplier


Torque multipliers are tools that accept input torque and increase the torque via planetary gear reduction. This creates a mechanical advantage for hard-to-torque assemblies, such as fasteners and valves.




Input torque is provided by manual, electric, or pneumatic means. This input drives the primary gear of an epicyclic transmission, which in turn rotates the planet gears around it. Connected to the output shaft, the number of planetary gear stages determines the ratio of torque input to output.


Torque multipliers are considered safer than cheater bars, as the increased force exerts significant pressure on the tooling and workpiece, which could cause failure. They are preferred over impact wrenches when air compressors cannot be powered due to insufficient power supply.




  • Input torque: the amount of torque the tool can handle on the input side, in ft.-lb.. If too much input torque is applied then possible damage can be done to the tool.
  • Gear ratio: the ratio of input turns required to produce one output turn. A gear ratio of 3 or 3:1 would signify three complete input turns to one output turn.
  • Output torque: the maximum amount of rotational force the tool can produce.
  • Drive type: the type of socket adapter on the tool, which determines compatible sockets



  • Ratcheting: allows a torque multiplier to rotate freely in one direction
  • Multi-stage: A multi-stage torque multiplier will have an adjustable gear ratio selection.

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