How Does Pulling Work?
The goal of tractor pulling is to determine the strongest machine and the best driver. Different to every other motorsport in the world, it is not about the speed, but distance pulled. The pulling track is a minimum of 30 feet wide by 300 feet long. Competitors draw numbers and take there opportunity one pull at a time, to determine the furthest distance pulled. Pulling vehicles from each class feature somewhat similar power plants, and the field is made even by setting a maximum weight and height of hitch. This allows each pulling machine the same "opportunity" to make it out the end, and into a pull-off.
Tractor pulling is a competitive motor sport in which modified farm tractors, modified tractors, 4WD and 2WD trucks drag a metal sled along a predetermined course. The sled contains a box filled with weight that is mechanically winched forward as the sled progresses along the track. Pulling this increasing load eventually causes the vehicle to lose forward momentum, either through power or tractor, although a rare few might indeed reach the end of the course, known as a “full pull.” The distance from start to finish is measured in thousandths of an inch and the tractor that pulls the sled the farthest distance is declared the winner. If more than one competitor reaches the full pull mark, a pull-off is held to determine a winner. Pull-offs offer some of the most exciting clashes in motorsports, pitting the top performing competitors against each other in a "winner takes all" finale!
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. Various classes have been developed for tractors based on limitations in the rules. Modified tractor limits are based mostly on weight. Engines include drag racing automotive type, jet turbines, aircraft and industrial engines in various configurations. Trucks come in two wheel drive, four wheel drive (naturally aspirated, blown, diesel) and semis. Fuels used range from Diesel, Gasoline to Alcohol.
Below is a video from the NTPA, explaining the function of a pulling sled, or "Weight Transfer Sled". It's a great video to help newcomers to the sport of pulling understand how these massive, powerful vehicles are brought to a stop!