Tractor pull question

[rel14]

OK, I watch the pull on TV all the time,,  understand the need for horsepower,, the question is,,  why do they run slick tires,, I was always told, if your tires are spinning, your losing traction.   When I was working we used a 6000 lb, forklift with 90 hp, and moved 86 thousand pd, semi

trailer  into the work bays.  Tried lookin this up on the puter,, but can't find the answer,, Maybe someone here can shed light on it,,,    a 100 hp caterpillar will move that slide any were..   I think ( which gets me in hot water) that more bit, and a granny gear will  it easier,,,?

theres a u-tube were a 20 hp flywheel tractor was hooked to a 4 engine puller,,and the old flywheel pulled it backwards with no problem,, I'm missing something here, or its a lack of education,,           Thank you

 

[DrKerry]

I know the way they cut the tires helps, not sure why they cut them short though!!

[Fat Brian]

There are different ways to pull, with torque or with horsepower. Modern pulling is governed by horsepower and for max horsepower you need high rpms which means high wheel speed, that's why they use cut tires so as to not take too big of a bite. Farm tractors pull with torque which means they need big cleats on the tires to transfer the engine power and if the tires spin you lose pulling power. Go to youtube and find the channel Pulling Reference, if you watch the really old videos from the early to mid Eighties they will talk sometimes about the different tractors and how they are setup for either wheel speed or torque.

[1930fordpickup]

10 hours ago, rel14 said:

OK, I watch the pull on TV all the time,,  understand the need for horsepower,, the question is,,  why do they run slick tires,, I was always told, if your tires are spinning, your losing traction.   When I was working we used a 6000 lb, forklift with 90 hp, and moved 86 thousand pd, semi

trailer  into the work bays.  Tried lookin this up on the puter,, but can't find the answer,, Maybe someone here can shed light on it,,,    a 100 hp caterpillar will move that slide any were..   I think ( which gets me in hot water) that more bit, and a granny gear will  it easier,,,?

theres a u-tube were a 20 hp flywheel tractor was hooked to a 4 engine puller,,and the old flywheel pulled it backwards with no problem,, I'm missing something here, or its a lack of education,,           Thank you

 

You need to go the pulls live and go in the pits.  Are you talking about the Steam tractor?  You just can't stop steam in the unlimited class.  My friend had a few steam tractors at this house they are cool. 

[DRIPTROIT 71]

Cut tractor pulling tires are cut so that there is a sharp leading edge for traction. Believe it or not they will pull better than uncut tires even in 3 1/2 mph stock tractor classes. They also don't turn into shovels like stock tires while spinning. High horsepower engines general make high horsepower at high rpm. They must spin the tires to achieve that. If their tires are performing like shovels they will dig holes. Holes are the last thing that you want in tractor pulling. Traction also depends on the soil of the track. Along with cut tires, tractor pullers move weight around and adjust air pressure, depending on the track to achieve the best traction.

You also need to remember that there are weight classes and regulations in tractor pulling. A heavy tractor will less horsepower can move a lighter tractor with major horsepower.

There is also the drag effect of the sled. The weight climbs to a point of being directly over the pan dragging against the ground. Drag will depend on the soil as well as the sled itself. A few years ago the local antique tractor pulling association welded angle iron under the pan that would actually dig in when the weight was over it.

There is also the angle of the pull. This is why there are height regulations on the hitch. Pulling up on the sled decreases drag while increasing weight and traction on the rear tires.

Tractor pulling is more than simply moving weight from one point to another. To those who are serious there is a lot of math and calculations. With that being said, most tractor pulling tractors would not be very efficient as a tow vehicle around the shop, and the average piece of equipment would not be efficient (meeting all regulations) in tractor pulling.