Tractor pulling is a competitive motor sport in which modified farm tractors drag a metal sled along a prescribed course. The sled contains a heavy load of metal plates that are mechanically winched forward as the sled progresses along the course. Tractors pulling this ever-increasing load eventually lose forward momentum and torque, although a rare few might indeed reach the end of the course. The distance from start to finish is measured in hundredths of an inch (a few millimeters), and the tractor that pulls the sled the farthest distance is declared the winner. If more than one tractor reaches the end of the course, a run-off is held using heavier weights or a greater distance.
Competition-level tractors might look like standard-issue farm equipment, but the similarities stop at the basic body and tires. Tractor pulling is a sport based on horsepower and torque, which means that the engine must be modified to generate as much power as possible. The tractors in many competitions generate 2,000-3,000 horsepower, and elite competitions might feature tractors capable of 10,000 horsepower or more. Some tractor pull enthusiasts have even been known to modify semi-trailer trucks for high-end competitions.
Engines in competition tractors are often modified with parts intended for drag racing and other motor sports. Designers must be careful to balance power with safety, because these engines are intended to run until complete failure. Drivers must follow strict rules in organized tractor pulls, including the use of a roll bar and engine kill switches. If a driver should fall off the tractor, the engine and fuel delivery system must automatically shut down immediately.
During a tractor pull, the driver must keep his or her tractor within marked boundaries. Touching either boundary line results in disqualification. This is an important safety feature, because spectators might be seated in temporary bleachers near the course. There are national and international tractor pulling associations that set guidelines for competitions and oversee local and regional chapters.
Some spectators find tractor pulling to be challenging to watch. Numerous classifications of tractors must race throughout the day, and the winning efforts are not always apparent to those in the stands because the differences in distances might be very small. Competition tractor engines also can be extremely loud, so hearing protection is recommended for every spectator, especially young children. Occasionally, an engine under extreme pressure will explode, sending dangerous shrapnel in all directions. No one except trained professionals should stand near these tractors during competitions.
