Tractor pulling is the struggle between the Tractor and the Sled. This is a kind of
trailer, with wheels at the tail and a flat plate on the front. The issue is to drag the
sled as fare away as possible, across a 100m (300 feet) track. The difficulty is that
along the track, the sledge becomes heavier. At he beginning of the pull, a carriage
loaded with steel plates is above the wheels. Along the track, this carriage moves to the
front and generates a larger pressure on the plate on the front. This causes an ever
increasing drag. The tractor will eventually not be able to go any further. The goal is to
use a combination of force, speed and balance that the 100m line is passed. This goal is
called a 'full pull'. Full pulls in less then 10 seconds are possible. And this when the
total weight of the combination is about 20.000 to 25.000 kilo ! (45,000 to 55.000 lbs.)
To reach the finals, they also run a 'pull off'. In this run, the sleds parameters are
adjusted to increase drag. This can be reached by several ways:
Let the carriage move faster, by changing the gear setting.
By mounting steel stripes under the sledge-plate.
To make the carriage heavier, by adding 2,5 metric tons (6000 lbs.) of steel weights.
Might a tractor break away from the sled, or the driver gets in trouble, then the
sled-operator can put the emergency-cable into action. He pulls a cable, that's connected
to the tractor. This cable for example turns of the ignition of the tractor, and make it
stop.
If this doesn't help, then there is a pile of dirt at the end of the track to stop the
tractor. Also there is a 10m (30 feet) safety-margin between the track (width 30 feet) and
the spectators. Sometimes a safetyrail is mounted alongside the track, like highways have.
The most of today's sleds have their own engine. By lowering 2 wheels next to the
sled-plate, the sled can roll itself back to the start of the track. They also have some
kind of steering, by slightly rotating the sled-plate. Often a team chooses the
starting-position of the sled. By locating it on the right side of the track, they create
more margin at the left site. This is done if the team assumes the tractor will deviate to
the left during the pull.
