More is better...Less is better...

[Rick Jay]

Yeah, I can picture that easy enough IF only the front axle were there. And I realize that the force of gravity from the bucket and contents is straight down towards the center of the earth.

Where I get a bit fuzzy in the whole analogy is that the bucket is connected to the loader frame which connects to a point mid-way between the front and rear axles.

The tractor will pivot around the front axle, but isn't atleast part of the applied force on the rear axle side of the pivot point, where the loader frame connects to the tractor?

I understand the force of the loader bucket pivoting the tractor around the front axle. What I'm not clear on is how much, if any, of that force is distributed through the tractor frame toward the rear axle.

Now you guys know why I went E.E. /w3tcompact/icons/smile.gif.

What I would love to see is a tractor with a scale under each wheel with an empty bucket and then again with a known load in the bucket. That should tell how the weight is distributed when the bucket is in the carry position.

I'm sure all the force must get transferred to the tractor frame, or else they wouldn't have to reinforce all that metal in the loader supports.

I should go dust off my old Statics/Dynamics book, but just the thought of that is bringing back some pretty horrid memories. Yuck.

Can we talk about tractor electrical systems instead? /w3tcompact/icons/laugh.gif

~Rick

 

[rdbrumfield]

the only down force on the rear tires from the loader is from carrying it. As soon as you start to apply weight to the bucket it start to lift the weight off the back tires. basically you are lifting the back of the tractor with the rear mounting points of the loader and shoving down with the front mounts.

 

[Maurice]

I finally saved enough to have 2 cents to add.

The way I can visualize it is laying a 2X4 over 2 blocks with the ends hanging over a foot or two. At this point both blocks are supporting equal amounts of weight. Add weight to one end, maybe the front, the front support will now have a higher percent of the over all weight on it. However if you add weight(balast) to the back end the percentage decreases even though the over weight being supported has increased.

Might be kinda simplistic, but does it sound right?

 

[Rick Jay]

O.K., I think I'm shaving some of the fuzz off my thinkin'.

The force due to the weight and any load in the bucket is downward at the bucket. Since this is on the opposite side of the pivot point (front axle) from where it's attached, the loader support brackets are actually exerting an upward force on the tractor frame. Thus it's trying to pivot the tractor about the front axle by lifting it from where the loader attaches to the frame of the tractor.

This lifting force is always there (unless the bucket is resting on the ground) whether the bucket is filled or empty. Obviously, more weight in the bucket increases this lifting force behind the front axle, thus "encouraging" the tractor to tip forward about the front axle.

I'm glad I went E.E.

~Rick

 

[MDNick]

Rick,

I can see your confusion, but it doesn't matter a darn where the weight connects to the tractor. What matters is where the weight is and how far from the pivot points (both axles). You could have 2,000 lbs 20' behind the rear axle bolted on a chunk of angle iron that runs all the way to the grill, and it's still the 20' behind the axle that matters. It's all a system of weights and balances, with the weight pointing mostly straight down (neglecting the negligble fact that the earth is a sphere and gravity points to the center, most CUTS aren't long enough for that to matter)/w3tcompact/icons/grin.gif.

My take on all this (yes, I have a phsyics degree) is fairly simple. As much weight on the rear end as possible. The more the merrier. Pile it on. Wheel weights and loaded tires are the best. If you are lifting the rear end off the ground, you don't have enough weight. Period. Even connected to an immovable object, you should run out of hydraulics before a loss in gravity. Yes, all weight picked up by the FEL is on the front axle, and lightens the rear end (which puts that rear weight onto the front axle). Conversely, all weight behing the rear axle is on the rear axle and lightens the front end. As stated previously, the rear is much beefier, so rear weight is good. Anything you can pick up with the FEL should not hurt or endanger the tractor. And with enough weight on the rear end, any weight in the FEL won't matter on any slope you would take the tractor on empty, within reason. At some point common sense has got to take over. If I have 1,000 lbs of ballast on the 3pt, and pile in (note that you must put it in by hand, my FEL couldn't pick this up) 2,000 lbs of lead in the FEL and take it over a 30 deg slope, I am going to have a problem. Well, I wasn't real bright and was asking to die. I had it coming. Most likely the world would be a better place without me.

Weight is good.
More weight is better.
As much as you can pile on (within intelligent reason) is best.

 

[Rick Jay]

MDNick,

Thanks, I've been mulling it around in my noggin' and it all makes sense now. I was just getting a bit caught up on the loader attachment. I knew it didn't seem right, but just took me awhile to reason it all out.

Actually, that's better than when I was in college. Back then I used to figure it out about 2 weeks after the test. /w3tcompact/icons/laugh.gif If I was this quick in college, maybe I would've gone M.E. Naaaaahhhhhh...... /w3tcompact/icons/smile.gif

~Rick

 

[rdbrumfield]

Just keep in mind that those little bolts-nuts between you legs that hold the front part of the tranny to the back part, actually only the top few are what is keeping the rig in one piece when you pile on all that weight. I have seen how ugly it can be.

 

[OkieG]

I am among those of you who would like to think that if the loader can pick it up, the rest of the tractor should be able to move it w/o undue wear and tear.

If I understand MDNick, I think he has it right. Any weight behind the front axle will help keep the back tires on the ground (using the front axle as the pivot point). The farther behind the front axle the weight is, the better able it is to keep the back tires planted (longer moment arm). As weight is added behind the rears on the 3pt, the rear axle becomes a pivot point, too.

If the rear tires are on the ground in the first place (even if they're light), 3pt ballast will actually lighten the weight load on the front axle, because the 3pt weight will use the rear axle as a pivot to lighten the front.

So, filled tires and rear tire weights will help keep the rears on the ground, but will not lighten the load on the front axle like weight on the 3pt will.

OkieG

 

[Rick Jay]

Yup...I think that's the way I understand it. But what do I know? /w3tcompact/icons/laugh.gif

~Rick

 

[OkieG]

<font color=blue>Wheel weights and loaded tires are the best.</font color=blue>

Actually, in the context of a full loader bucket and concern about "overloading" the front axle, I may disagree with Nick on this one point.

Wheel weights and loaded tires are good, but 3pt weight might be better. /w3tcompact/icons/smile.gif Not only keeps the rears on the ground, but may ease the load on the front axle.

OkieG