Sled Pulling
In the early days two main techniques were used. Either a dead weight of fixed mass was dragged, or the step-on method was used, where people stood at fixed positions and stepped aboard as the sled passed. Another rule which has now been dropped was that a speed limit should be observed because of injuries resulting from the increased speed at which they boarded. Today's tractors can achieve theoretical speeds over 125 mph.
Today's sleds use a complex system of gears to move weights up to 65,000 pounds/29,000 kilograms. Upon starting, all the weights are over the sled's rear axles, to give an effective weight of the sled plus zero. As the tractor travels the course, the weights are pushed forward of the sled's axles, pushing the front of the sled into the ground, synthetically creating a gain in weight until the tractor is no longer able to overcome the force of friction.To help stop the sled some sleds have grouser bars that act like teeth and dig into the soil to stop the sled.
Read more about this topic: Tractor Pulling
Famous quotes containing the words sled and/or pulling:
“I weathered some merry snow-storms, and spent some cheerful winter evenings by my fireside, while the snow whirled wildly without, and even the hooting of the owl was hushed. For many weeks I met no one in my walks but those who came occasionally to cut wood and sled it to the village.... For human society I was obliged to conjure up the former occupants of these woods.”
—Henry David Thoreau (1817–1862)
“Why must it always end this way?
A dais with woman reading, with the ruckus of her hair
And all that is unsaid about her pulling us back to her, with her
Into the silence that night alone can’t explain.”
—John Ashbery (b. 1927)