What Is Lawn Mower Torque?

Lawn Mower Power

• Technically speaking, one horsepower equals 747,699 watts of electrical power. Over the years, manufacturers of automobiles, lawn mowers and other small engines began stretching the definition of horsepower to make their engines appear more powerful than they actually were. In January 2010, the EU restricted the use of horsepower to supplement cubic centimeters displacement and other ways to rate engine power.

Class Action Lawsuit

• A successful 2010 class action lawsuit in the U.S. accused lawn mower manufacturers of collusion in listing inflated horsepower ratings. After settling the lawsuit, manufacturers began turning to torque as the primary measure of power.

Torque Basics

• To better understand torque, the physics department of the University of Guelph in Canada asks you to imagine closing a door. The force required to push the door shut is torque. The closer you are to the hinge, the harder you have to push to shut the door. The same principle, torque, is used to measure the amount of force a lawn mower applies to a spinning blade.

Lawn Mower Torque

• The Society of Automotive Engineers code for rating small engines measures torque in foot pounds. Lawn mower torque is the amount of foot pounds required to spin the cutting blade 3,060 rounds per minute. Lawn mower manufacturers and dealers dislike using torque to rate lawn mower power because they think consumers do not understand it. Critics say manufacturers are twisting the term just as much as they did horsepower and it will eventually become just as meaningless. In time, these critics say, manufacturers will return to using horsepower as the primary rating of power.