Tractor horsepower

Measuring tractor horsepower is not so simple. Like any other measurement where more is better -- such as audio amplifier watts or car miles-per-gallon -- manufacturers have devised ways to one-up the competition in the game of "specmanship." Many tractor manufacturers simply rate their equipment with the horsepower rating of the engine, ignoring the fact that this energy must be transferred through the tractor's drivetrain to the wheels or PTO in order to be useful. Others contrive unrealistic test conditions that encourage one brief measurement of high horsepower, which is then used to rate the tractor, even though the machine is unlikely to ever perform that powerfully in actual use. In fact, misrepresenting tractor horsepower is a pretty old game. Today’s compact tractor horsepower is determined by measuring crankshaft power, so vintage and modern horsepower ratings aren’t the same. An antique tractor in the 25-horsepower range can power a small, PTO-driven square baler but a bigger oldie is a better investment in muscle and versatility.