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How does the sled work

29K views 15 replies 7 participants last post by  greggf34 
#1 ·
I been watching a lot of tractor pulls and truck pulls and i cant understand how the sled works. someone told me that they dig into the ground that doesnt seem right, if it doesnt dig then how does it get heavier the trailer that you hook to is as heavy as its going to get not matter what without adding more weight, why when you move does the shifting of the weight make such a huge differance. thanks for the info
 
#2 ·
I think the sled slides across the ground, and the weights are different for each class, but the further you go the further the weight moves towards your truck, therfore putting more weight on the back of your truck, increasing the load.... Thats how I think it works but I have never hooked to one. Just watched.
Somebody more knowledgable fill free to fill in some blanks or correct me if Im wrong....
 
#3 ·
I think the sled slides across the ground, and the weights are different for each class, but the further you go the further the weight moves towards your truck, therfore putting more weight on the back of your truck, increasing the load.... Thats how I think it works but I have never hooked to one. Just watched.
Somebody more knowledgable fill free to fill in some blanks or correct me if Im wrong....
i think that's how it works too
 
#4 ·
Thats my understanding, hopefully Im right or somebody and expert will chime in.
 
#5 ·
Drty you were right on the money.

Gotta love wikipedia:
"The sledge is known as a weight transfer sled. This means that as it is pulled down the track, the weight is transferred (linked with gears to the sledge’s wheels) from over the rear axles and towards the front of the sledge. In front of the rear wheels, there is a "pan". This is essentially a metal plate and as the weight moves over this the resistance builds. The further the tractor pulls the sledge, the harder it gets."

Tractor pulling - Wikipedia, the free encyclopedia
 
#9 ·
Thanks. I was just giving my understanding on it.. Glad it was right.
Basically, the sled is designed so that fro the start you are pulling very little weight, but the weight increases as the distance pulled increases.



the Bauer-built sleds have grousers underneath the pan (along with a slightly concave pan), based on the idea that after a couple pulls, there will be a build up of dirt under tha pan, so you are pulling dirt on dirt, rather than a flat steel plate on dirt.

The weight box is driven further forward as the distance pulled increases, gradually increasing the load on the pan. There may also be a hyd cylinder form the rear of the pan to the frame. This can be used in to transfer nearly all of the sled's weight onto the pan.

On a simple primitive sled, this could all be geared from the ground wheels on the sled. Modern versions would use hydraulics and electronic controls to vary the speed of the box, etc. This way, the load is repeatable for each competitor, but can be changed for another round of pulling.
Thats interesting, I havent seen any of the higher end sleds. Just some local run of the mill sleds. Id like to start going to some of the bigger truck & tractor pull events
 
#6 · (Edited)
high end sleds (Bauer's Ironman sleds for example) in tractor pulling do indeed have bars that push down into the ground under the pan. I'm sure there are plenty of sleds around that do not do this though and simply use only the weight box.

Edit: like everything else on these sleds, the point at which this is engaged is configurable. It definitely hits 'em hard when this kicks in.
 
#7 ·
Basically, the sled is designed so that fro the start you are pulling very little weight, but the weight increases as the distance pulled increases.



the Bauer-built sleds have grousers underneath the pan (along with a slightly concave pan), based on the idea that after a couple pulls, there will be a build up of dirt under tha pan, so you are pulling dirt on dirt, rather than a flat steel plate on dirt.

The weight box is driven further forward as the distance pulled increases, gradually increasing the load on the pan. There may also be a hyd cylinder form the rear of the pan to the frame. This can be used in to transfer nearly all of the sled's weight onto the pan.

On a simple primitive sled, this could all be geared from the ground wheels on the sled. Modern versions would use hydraulics and electronic controls to vary the speed of the box, etc. This way, the load is repeatable for each competitor, but can be changed for another round of pulling.
 
#15 ·
Think they sell a couple every year. Bauer-built manufactures planters for Deere (DB series) and every year they shut down for a coulpe weeks to build the new sleds. They have a few that they run and own through the year, then sell them as they get old if I remember right. Had a couple buddies who interned for them during college, and they were a sponser to our 1/4 scale pulling team.

Another college buddy designed a new sled for our pulling team based off the bauer sled, and they were very helpful with the design and supplying materials, powdercoat and advice. Visited theur shop a few times. Seems like a very relaxed, family owned company.
 
#16 ·
Been pulling my entire life so I have watched the evolution of the sled. They used to simply be a transmission hooked to the rear axle which propelled the weight box up the rails. By changing the gear in the transmission, you could change the speed of the weight box to stop pullers at the desired distance. This transfer of weight from the rear wheels on the "pan" created more friction and thus made it harder to pull. These sleds were very slow to pull and hard on vehicles. The answer to this problem was to design a sled that was lighter to get moving and allowed more speed down the track but could still stop the pullers. This was accomlished by making the pan lighter but adding hydraulic down pressure or grouser bars, or both. Pullers could get moving and build speed but the sled could still stop them because when the box reached a certain point on the rails, the hydraulic down pressure is tripped and the back end of the sled is lifted nearly off the ground transferring almost all the weight to the pan. Some vehicles are still hard to stop even with this once they have built up speed. So grouser bars can be used to stop them. These are also tripped when the box reaches a certain point and push down out from the bottom of the pan to creat even more friction. By the way, bauer does make the nicest sleds but typically aren't used that much for street legal pickups.
 
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