Max drawbar pull

Anonymous-0

Well-known Member
On the external_link website, under tests, there is max drawbar pull. Does anyone know how those numbers relate to the ability of the tractor to pull tillage equipment. Tractors in the same hp range, weight range, and year built, may have large differences in the max pull weight. Is this an accurate way to determine which tractor will pull larger equipment, assuming the same soil conditions.
 
They may have the same HP and weight but where is that weight? The balance of weight between the front and rear of the tractor makes a big difference.

Guys that compete in tractor pulls may move 100 pounds from the front to the rear to get an advantage.

Gary
 
It is a waste of time comparing "max drawbar pull" from external_link. It only lists the highest pull recorded by the University of Nebraska. That's typically going to be in the lowest gear, but do you expect to pull all your implements in first gear? To get meaningful comparisons, you need to go back to the source material.

For example, I pulled at random the specs for a New Holland T4020.

external_link says:
Max pull: 6995 lbs
Drawbar horsepower: 49.95 hp
Max pull gear: 1ML

Nebraska tractor test says:
3rd gear (1M): 6275 lbs, 38.4 hp, 2.29 mph
4th gear (3L): 4820 lbs, 44.3 hp, 2.85 mph
5th gear (2M): 5005 lbs, 47.4 hp, 3.55 mph
6th gear (4L): 4220 lbs, 50.1 hp, 4.45 mph
7th gear (3M): 3620 lbs, 50.8 hp, 5.26 mph
8th gear (1H): 2725 lbs, 51.1 hp, 7.03 mph
9th gear (4M): 2230 lbs, 48.6 hp, 8.18 mph
10th gear (2H): 1685 lbs, 47.7 hp, 10.62 mph

Several things should be readily apparent:
The external_link information isn't correct.
The external_link information, as presented, isn't useful even if it was right.

What you should be looking at is to first consider the speeds at which you expect to pull your implements. Then look at both DRAWBAR HORSEPOWER and SPECIFIC FUEL CONSUMPTION at those speeds. The drawbar pull by itself is NOT USEFUL INFORMATION without knowing the speed. That's because horsepower equals force times speed. In the end, drawbar horsepower and specific fuel consumption are the only measurements that matter. The first tells you how fast you can get the job done and the second tells you how much fuel it will take to do the job. Drawbar pull by itself DOES NOT MATTER.
 
The Nebraska Tests are conducted on concrete pulling a weight with a load cell between the tractor and the weight connector. This data can only be used to compare one tractor tested there againts another tractor tested there.

You can also calculate the drawbar horsepower (drawbar HP=(drawbar force~lbs X speed~ft/sec)/550 from the test points and from that determine the max drawbar power as a function of gear and ground speed. That will tell you the gear to get the most drawbar work done per unit time.
Your soil conditions will be different from the test condtions but this data gives you a starting point to figure out where you should operate your plow.
 

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