Traction old vs new - it's not always hp - interesting video

[aczlan]

So the uninformed answer is thatif the chain was level the JD had a chance? Is that really where going with this? The chain is irrelevant in this. Lower, higher, even, the JD would have gotten beat. Its a weight and torque thing

I agree with the above, if you interpreted my post to infer otherwise, you misread it. I said "Would it have made a difference in this case? No, the steamer had too much of a weight advantage"

However, from the point of view of what happened to the Deere as it was pulling, as the chain comes tight, the machine with the higher hitch point gains weight on the axle closest to the hitch while the machine with the lower hitch point loses weight on the axle closest to the hitch point. Here is an example of a pickup "gaining" weight on the rear axle when it pulls up on a tree:

Watch the back end squat a little as the chain comes tight. The exact same thing happened to the steamer when the Deere started pulling. If the one is being pulled down, the other must be pulled up (unless there is another pivot point in the mix).

If you had that Deere hooked up to an identical Deere (same engine, weight, gears, etc) and had one hooked at 18" off the ground and the other at 28" off the ground, the one with the higher hitch point will win (as long as the higher hitch point doesn't cause it to roll over) because it will gain weight on the rear axle as the other tractor loses weight on the rear axle. As such, the one with the 18" hitch point will dig into the ground more than if they were hitched level as when it loses weight it loses traction. Will the angle change? Probably not much, the Deere with the lower hitch point might come up 1/2", but it will when it loses traction it will start digging in like the Deere in the video did (rather than doing a wheelie).

Aaron Z

 

[k0ua]

I agree with the above, if you interpreted my post to infer otherwise, you misread it. I said "Would it have made a difference in this case? No, the steamer had too much of a weight advantage"

However, from the point of view of what happened to the Deere as it was pulling, as the chain comes tight, the machine with the higher hitch point gains weight on the axle closest to the hitch while the machine with the lower hitch point loses weight on the axle closest to the hitch point. Here is an example of a pickup "gaining" weight on the rear axle when it pulls up on a tree:

Watch the back end squat a little as the chain comes tight. The exact same thing happened to the steamer when the Deere started pulling. If the one is being pulled down, the other must be pulled up (unless there is another pivot point in the mix).

If you had that Deere hooked up to an identical Deere (same engine, weight, gears, etc) and had one hooked at 18" off the ground and the other at 28" off the ground, the one with the higher hitch point will win (as long as the higher hitch point doesn't cause it to roll over) because it will gain weight on the rear axle as the other tractor loses weight on the rear axle. As such, the one with the 18" hitch point will dig into the ground more than if they were hitched level as when it loses weight it loses traction. Will the angle change? Probably not much, the Deere with the lower hitch point might come up 1/2", but it will when it loses traction it will start digging in like the Deere in the video did (rather than doing a wheelie).

Aaron Z

That was an excellent video to illustrate your point, as was the idiots with the car and the tree hitch at 50 foot high.

 

[xtn]

Torque is certainly required, or there would have been no contest to begin with. But both tractors had plenty of torque relative to other factors, namely traction. So the differing amounts of torque produced by the two was not a factor in the outcome. Thus all the silly discussion on Youtube about how much torque the old tractor was just irrelevant. If the JD had more traction (lots more) relative torque output might have been a factor, but as it played out, it wasn't at all.

Terry

Okay I gotcha.

 

[DarkBlack]

The JDs traction was the same at the beginning of the pull as the end.

The steamer never did anything statistically significant to lift the JD that would change or reduce the traction. Your misunderstanding of physics leads you to the belief that the JD is being pulled "up" somehow, reducing its traction. The fact that it buries in indicates that the total vector of the system is to the left of screen and DOWN, not up.

Same as a sled pull: the reason pull vehicle sinks as it runs out of forward velocity is the impact of the downward component of the sleds total vector on the system. This steamer, due to its weight has a monstrous downward component to its vector and the result on the system of steamer, chain, JD.

My Ram 2500 diesel will out pull 500 HP Dakota all day long regardless of chain angle.

You're totally wrong.
The JD started on hard-pack, and finished on loosened dirt- totally different traction.
Not only is there less traction in loss dirt, the pull angle increased more by digging down.

The JD's rear is being pulled upward. Sorry if you just don't get that.
Technically the steamer has a second advantage, and that is the distance of the pull connection point to the center of rotation in relation to the axle to ground distance. Modern tractors hitch low like the JD, for good safety reasons ( to prevent weight transfer to rear tires).
The fact that it spun it's tires and dug downward, doesn't mean the opposing force wasn't lifting up.

The steamer may have won no matter what by it's shear weight advantage, but the participants certainly didn't try to make it "fair" otherwise.

 

[k0ua]

The steamer may have won no matter what by it's shear weight advantage, but the participants certainly didn't try to make it "fair" otherwise.

I agree with this, The whole thing was a "show" not a "fair fight".. for instance why did the JD spin his tires at high speed? To make a big show..and till up the soil. How many of you have had good luck if when you lose traction, you open the throttle.? No-one with any experience would do that. But the steamer probably outweighed the JD by a factor of 4, so the JD never really had a chance. But I can tell you this, If hooking up 2 equal truck and I had money on the line, I sure as Heck, would want the hitch to be as the same height to be fair.

 

[xtn]

So the uninformed answer is thatif the chain was level the JD had a chance? Is that really where going with this? The chain is irrelevant in this. Lower, higher, even, the JD would have gotten beat. Its a weight and torque thing, you wouldn't understand.

I understand completely. No, the outcome surely wouldn't have been any different even if the chain had been level. But even though the total vector on the JD was in a downward direction - thanks to gravity of course - that vector was less than it could have been because PART of the total is a small upward vector component caused by that chain.

 

[Turbys_1700]

When I see videos like this I think of the old adage "getting power to the ground"...
That old steamer is heavy and slow and has a weight advantage...
It is getting all of it's pulling power and weight to the ground...
The Deere is spinning out a lot of it's power...
If both tractors were even in power, weight, torque, and traction, the angle of the chain would come into play...
In this example, it would not...
They are not equal...

 

[Tenn_Blue]

Another (nonrelated - so maybe people will see it without their investment in this thread...) example of where weight DOES affect traction is with race cars. Formula cars have ground effect bodies and wings to increase downforce on the vehicle. This increases friction and adhesion at the contact patch (tire/road) allows higher turning (lateral force) speeds and traction without wheel spin.

OR in NASCAR, a change in downforce caused by turbulence from a passing vehicle or airflow change can send a car skidding and sliding, where it had good traction before.

Torque is only effective if it is being applied to the ground. Once wheel slip occurs, any additional torque is wasted energy. That's the concept behind anti-lock brakes!