- Category: Dualla History
- Written by Conor Breen
How did Tractor Pulling start?
At the start of the 20th century, agriculture in the US was booming. The development of land involved removing rocks and debris using horses. One farmer would tell another that he had moved a larger boulder. Heated discussions would take place and competitions started.
Eventually the 'dead-weight-sled' was introduced in competitions. The sled was connected to the tractor with a chain. It was all or nothing: the tractor either took off with the sled or it lost grip and dug itself into the track. To gain more traction, weights would be added to the tractor.
Later on the idea came up to make the sled heavier as it traveled along the track. This was achieved by having volunteers stand next to the track and step onto the sled as it went by to add weight as it progressed down the track. The sled was called a "stop-on-sled". The further the covered distance, the higher the position. If a tractor made it to the end of the track this was called a "full pull" which qualified for the finals of that day.
As tractors were getting bigger and more powerful, finding volunteers became harder, because the step-on-sled was going faster and faster and safety became an issue. To solve this, the "weight-transfer-machine" was developed. This sled had wheels at the rear end. At the start of the pull the weights are placed above the wheels. When the tractors started to pull the weights are transported forward towards the sled-plate by a chain. As friction increases between the sled-plate and the tractor, the tractor loses grip. This principle is still being used today.
The best pull is achieved when the tractor has a quick start. At the start of the track the sled is easy to pull, so a lot of speed can be developed. Nowadays the trag kills the tractor's engine at about 70-80 meters.
At a tractor pulling event, it's not only power that makes a tractor win. It's most important that the tractor is balanced correctly and you will often find with standard tractors that a 120hp tractor can sometimes beat a 160hp tractor.
How does the Sled Work?
Tractor pulling is the struggle between the tractor and the sled. This is a trailer with wheels at the end and a flat steel plate on the front. The carriage which sits on a track and can be moved forward hydraulically, is loaded with steel weights. The Irish Truck and Tractor Pulling Association's sled is called "Paddy's Anchor".
The object is to drag the sled as far up the 100m track as possible. The difficultly is that along the track the sled becomes heavier. At the beginning of the pull, a carriage loaded with steel plates is above the wheels, as the sled is pulled along the track the carriage moves from the back to the front and increases pressure on the plate at the front. The is causes tan increasing drag on the tractor which will eventually not be able to go any further.
The goal for the driver is to use a combination of good starting gear choice and balance so the 100m line can be passed and a "full pull" achieved.
In the pull off, the sled's parameters are adjusted to increase drag. Extra drag can be achieved by the sled's operator making any of the following adjustments:
- Let the carriage move forward faster, by changing the gear setting
- By lowering steel spikes under the sledgeplate increasing the drag.
- Making the carriage heavier by adding steel weights to the end