Chain and Drawbar length...

Derrick aka mh44six

I've been experiencing the same thing for the past couple of years with my JD. I always hooked short and high and figured that was the best scenario. After being consistently beat by my brother who has a quick hitch on his Farmall that is hanging out the back at near 30" from the rear axle I decided to do some calculating. We definitely have to add substantially more weight on the front of the Farmall to keep it down. I put together a spreadsheet that calculates the amount of weight transfered to the rear wheels and varied the position of the weight added to the tractor and the length of the drawbar. Assuming my formulas are correct, the result shows that regardless of weight position or drawbar length combination, once the front end has tranferred all the weight to the back wheels you have reached the maximum traction condition possible. For a given center of mass too short a drawbar will not tranfer all of the tractor weight to the rear wheels, to long a drawbar will not tranfer all the sled weight possible to the rrear tractor wheels. The part of this that gets sort of hard to predict is how much traction will the track conditions support? You could take cone readings and there are fomulas that would allow you to try and predict the right drawbar length for a given tractor and track, I've never seen anybody doing this at any of the pulls I've been to though.