As fun as testing this kind of thing would be in theory, it has no practical use or meaning.
A 4wd tractor with R1 tires and 4000lb 50hp dont care if its painted red, blue, green or orange. They are gonna pull the same amount.
Two parts of "pulling" is drawbar power, and max pulling force.
As mentioned, for max pull, a wheeled machine can usually be around 70% machine weight. TRACTION is the limiting factor. And with different soil conditions (moist, wet, mud, loose, dry packed, asphalt, etc) and different tires.....way too many variables. So what if someone across the country tests a tractor that can max pull 4000lbs......and you have the exact same tractor and want to pull a log that only requires 3500lbf and you cant move it because you spin. Maybe the ground is uneven, or slight grade, etc. Its not a real useful piece of information. And pretty much ALL tractors have a gear or range low enough to spin the tires. meaning power is never the problem....only traction.
Now drawbar HP.....that can come into play trying to pull something at speed. Alot of tillage equipment dont work well at slower speeds. They like 4-5mph to properly turn soil. So you may have a tractor capable of pulling a given size disc or plow....but simply lacks the power to do it at speed.
This topic comes up alot when people are questioning/comparing a couple of machines....that are the same basic machine but different HP ratings. Like a deere 5055 vs 5075.....or a 'bota MX5400 vs Mx6000, or any one of a dozen other examples I could cite. Too many times people say you will only notice the extra power if you are using the PTO heavy, and that if you are working ground engaging implements that its the weight and you wont notice the power. But that isnt always the case....if you are trying to maintain a certain speed.
If they're giving the result in HP, I assume the pull test is being done on a moving load, not a fixed load? Horsepower is a product of both speed and force.
Put otherwise, ignoring traction, a 30 hp tractor can pull awful hard in low gear. Maintaining that pull at an acceptable speed, compared to a 60 hp machine, is the limiting factor.
Correct. Some old heavy iron @30hp could probably pull a 3-14 plow. but it would be at a snails pace and not do a good job turning the furrow because it simply lacks the power to pull the plow at a fast enough speed
I've only seen raw bar hp on large tractors. Never seen it on the smaller ones, which means there's a space for data to be collected.
For instance, I've never seen a drawbar hp rating on my M9960 nor on my B7500. Thus, I think it's a worthwhile endeavor to find out the pulling force of these "small" tractors.
That data can also be used to help a lot of people in their purchasing decision and drive more traffic to TBN, despite the efforts of certain people consistently peeing in other cheerios and driving people off.
Most people looking at buying a sub-100hp machine isnt gonna care about drawbar HP or max pull. Because they are buying a machine as a general purpose machine or a utility machine. And quite simply.....more engine HP, and more PTO HP....usually means more drawbar HP. And a heavier machine means more max pull. And since all those stats are well published....and there arent any variables to machine weight and PTO power.....its a better baseline for comparison than some arbitrary data collected where ground conditions, tire type, etc all come into play. So compiling a chart as you propose.....while bein fun, would only serve as a comparison tool and not accurate data. And as mentioned, weight and PTO power already serve as a way to accurately compare what tractor is gonna be a better "puller"
