You need balast or you will trash your front axle!!!! really?

[oldpilgrim]

Not calling anyone out because I have valued and enjoyed all of this discussion, but I do encourage some thought on this if you are still struggling. I noticed something here that a few folks are missing and it is critical.

When one loads a loader, or forks, or a grapple - that weight/force is not being placed directly in front of the axle like in the case of a snow plow on a truck. The loader connection points to the tractor are typically located closer to the operator station and thus the forces are distributed to both the rear and front axles through the tractor frame. It is the distance to fulcrum where the force acts that is important here. One can still load the bucket sufficiently to "unload" the unweighted rear, but point is you are not placing and distributing the force directly at and beyond the front of the front axle.

This concept allows fun center of gravity toys like this to function.

View attachment 458352

So - adding 1,000 pounds on your 3pt can easily and fully counter balance a full 1,000+ pounds in your loader due to where the forces are actually acting. In this case your loader force is always acting behind your front axle, and if the load is extended far enough forward, or heavy enough to push the center of gravity past the front axle, then it will tip up. (That would be the case where someone pushed down on the eagles wings and your finger is the center of gravity/front axle).

That tipping forward will never happen if you have proper counter balance beyond the rear axle, AND your operating front axle loads will be at or below a fully unloaded tractor scenario. Having counterweights protrude past the rear wheels is a little bit of a pain for agility, but placing just 500-1,000+ pounds a good distance outward of the rear axle will let you do wheelies all day with a completely full loader and a football team hanging off the loader. This is why I sometimes use a heavy duty cutter for counter weight as it places some of the weight at a greater distance and provides a greater force/moment acting on the rear axle fulcrum which in turn helps reduce the loading on the front axle in all circumstances.

To help with the wheels on ground vs lifted issue, think about the split second before your rear wheels lift off the ground. At the point, all four tires are still in contact and yet the force on your front axle is almost at its maximum stress. If you placed your pinkie finger on the loader bucket and pressed down, then the rear wheels would lift off the ground. The difference in force on front axle in those two scenarios is negligible. The force progression is continuous and nothing special happens when the rear wheels finally come off the ground. The force on the rear axle simply goes from one pound to zero pounds...

Conclusions:

1) Counter balance weight at almost any distance behind the rear axle can and will offset similar weights/forces added to the frame of the tractor and thereby front axle when using a loader. More weight, and or greater distance from the rear axle will amplify the effects of lightening the front axle load. The impacts are far greater than just a nominal 10% or so mentioned earlier since the loader is imparting its forces towards the middle of the tractor which is not too terribly much farther from the rear axle than are the ends of your three point hitch and added counter weights. (Box Blade, Cutter, etc...)

2) Center of gravity is important to understand as well as fulcrums and force amplifiers. (Distance from fulcrum, etc...) Front end loaders are designed to place the actual working forces as close to the CG as possible, but moving them up or down can change the situation drastically in seconds. This is why counter balance rear of the rear axle is so effective at correcting problems associated with overloaded front axles.

3) Perhaps your front axle might not break of wear out right away if not using proper counter weighting, but it is safer, makes the tractor handle better, and keeps the front axle loaded within its working limits so I would suggest it. (And so as not to be accused of being a hypocrite, I do use my loader without counter weighting from time to time for light work, so shame on me.)

Stay safe everyone!

View attachment 458360

this is what I was trying to get at in a humorous way in post 93. One person called me on it and the rest ignored it.

The weight of the fel and it's load is transferred to a point where the loader and the lift cylinder are attached, somewhere between the 2 axles thereby transferring some of a loaded fel's weight to the rear of the tractor.

Also the higher you lift the load the more weight is transferred to the rear axle. I have proved this many times in actual use.

When moving snow with my old Ferguson 2wd, I had a place in my driveway that had a spot where it went downhill very gently for only about a total of a 2 ft drop over 20 feet. If I drove down that drop, dropped the snow load and then tried to back up, if it was icy, I'd lose traction. If I lifted the empty bucket up 5 or 6 feet, enough weight would transfer to the rears so that I could regain traction.

It's not as simple as the sticks and weights exercise or the toy tractor example as presented in this thread. The front axle weight (and the rear axle weight) will vary because of the mounting position of the fel and it's cylinders and the height of the load.


BTW, when I took the bucket off my Fergie's fel, I could easily lift the frontend when the bh was on it, like in the pic.

 

[LD1]

Where the loader mounts is irrelevant. Its where the load is placed. ANY weight added forward of the front axle CL does NOT add weight to the rear. It takes weight OFF the rear.

Raising the load higher lesses the amount of weight taken from the rear axle, because you are simply moving the load closer (in the vertical plane) to the front axle.

Skid loaders and telehandlers have loader mounts that are even behind the rear axle. And adding weight in the loader bucket STILL takes weight off the rear tires

Oldpilgram....using a backhoe as an example......

Would you agree that a 3PH backhoe takes weight off the front axle?

What about if you had the same size/weight backhoe but was a frame mount that the frame attachment point is clear up at the front axle? Would that somehow act like a big revers counterweight and overload your front axle?

 

[oldpilgrim]

of course the point at which the loader is attached to the frame moves some of the weight to the rear... the further back it's attached, the more weight is transferred.

Why do you think that a skid steer has it's loader pivot over or even behind the rear wheels? It's not for looks. It's to move the weight back so it doesn't fall on it's face. Put the hinge point further forward and more weight moves to the front.

The further back, the more weight is on the back. The higher the load, the more the weight shifts to the pivot point of the loader resulting in more weight on the backend.

 

[k0ua]

Wow James that sounds like a hair raising experience! So the 3 point ballast would not have kept the rotation of the tractor around the front axle pivot from continuing?
Would have thought the 3 point arms/top link would at least keep the tractor from going over- unless it was to flip also?


I can't say that 3 point weight has not caused problems for me either...
One time trying to push dirt back with the Gannon boxblade the force caused an old weld to break on the left 3 point arm mount.
The left rear tire (14.9x 28) backed over the gannon and went up in the air (wife said 2 feet!) before I could get the clutch pushed in and slammed me into the ROPS ringing my bell pretty good.
Luckily No front axle damage was done :laughing: can't say the same for the mount on the Gannon and my pride,we all make mistakes and stuff does happen, hopefully we all learn from mistakes and experience.

Thats a good question, and also would the angle of the rollover have caused the rock to hit the ground before the point of no return? I don't know, but I pushed it back and the roll was in a static condition. I was not willing to find out if it would have went all the way over or not.. I was glad when the wife went around to the high side and dropped the loader joystick, and the high side tire then hit the dirt.

 

[4570Man]

of course the point at which the loader is attached to the frame moves some of the weight to the rear... the further back it's attached, the more weight is transferred. Why do you think that a skid steer has it's loader pivot over or even behind the rear wheels? It's not for looks. It's to move the weight back so it doesn't fall on it's face. Put the hinge point further forward and more weight moves to the front. The further back, the more weight is on the back. The higher the load, the more the weight shifts to the pivot point of the loader resulting in more weight on the backend.

Simply not true. How else would you mount the loader on a skid steer? If you move the arms forward it is going to compromise the lift height or move the load farther out which comprises load capacity. As you lift up the weight does redistribute to the rear axle, but simply because the weight moves closer to the front axle. A skid steer doesn't tip over because the load is much closer to the front axle than a tractor, and a skid steer is quite heavy to counterbalance the load. You could move the location of the arms anywhere on the machine and as long as the distance between the bucket pins and the front axle doesn't change it won't make any difference.

 

[gladehound]

Where the loader mounts is irrelevant. Its where the load is placed. ANY weight added forward of the front axle CL does NOT add weight to the rear. It takes weight OFF the rear.

Raising the load higher lesses the amount of weight taken from the rear axle, because you are simply moving the load closer (in the vertical plane) to the front axle.

Skid loaders and telehandlers have loader mounts that are even behind the rear axle. And adding weight in the loader bucket STILL takes weight off the rear tires

Oldpilgram....using a backhoe as an example......

Would you agree that a 3PH backhoe takes weight off the front axle?

What about if you had the same size/weight backhoe but was a frame mount that the frame attachment point is clear up at the front axle? Would that somehow act like a big revers counterweight and overload your front axle?

LD-1 is absolutely correct. And I am a non-professional engineer :laughing:

Sorry for busting zzvyB6 but I've know a lot of MIT engineers who couldn't engineer their way out of a paper bag!!

I had two different roommates in college, both engineers, who whenever they were stuck on a problem would ask me to explain it to them - because I was really good at that stuff. I was of course... a music composition major!!! (at the time)

I think there is a lot of confusion because people don't necessarily explain their positions clearly & completely (myself included). Or the reader doesn't understand what they are trying to say even if it is reasonably clear (myself included). Or the reader gets tired of reading all these long winded comments and quits halfway through to respond (myself included). And maybe one of these possibilities is the case with this example.

But in case it's not, if anyone thinks the attachment point of the loader makes a difference as to how much weight from a rock in the bucket of the FEL (not the fell itself) is transferred to the front vs rear wheels, that person needs to start a post # 1 of this thread and read the whole thing again! :laughing: If said person still believes the attachment point makes a difference, I suggest you seek empirical evidence of your claim (please be sure to adjust for the inevitable weigh shift when you move your loader attachment )

 

[gladehound]

Why do you think that a skid steer has it's loader pivot over or even behind the rear wheels? It's not for looks. It's to move the weight back so it doesn't fall on it's face. Put the hinge point further forward and more weight moves to the front.

You are absolutely correct that having a loader further back on a machine moves more weight to the rear compared to the front of a machine. You are absolutely incorrect that the hinge point has anything to do with it. It is completely dependent on where the weight is, not where the hinge point is.

Skid steers are designed how they are mostly to keep them compact. Also to keep the front wheels close to the load and minimize the leverage arm created by the portion of the loader/bucket that is forward of the front axle. Wheel loaders typically lift more weight than similar size skid steers and they don't have the pivot point in the back.

 

[murphy1244]

After 147 posts I've decided I'll keep the 1100 pounds on the 3 point. It works for me!

 

[k0ua]

After 147 posts I've decided I'll keep the 1100 pounds on the 3 point. It works for me!

A safe bet Murph

 

[oldpilgrim]

I'm not an engineer but I did take several years of physics in high school and college. Maybe the laws of gravity and deflection have changed since then.

Perhaps I've said it wrong.

The lift cylinder anchor point to the tractor is where the weight is actually lifted. The further back that lift point, the further back the weight is applied to the tractor. I incorrectly stated the pivot point of the loader.

With the skid steer, the pivot point is over the rear axle so the lift point of the cylinder can be further back so more weight can be supported by the rear axle (actually spread the weight more evenly over both axles by moving the weight to the rear).

If people say that is wrong, then it's a matter of semantics or you guys are all nuts!

 

[murphy1244]

A safe bet Murph

I ain't ended up in Oz yet but you never know. My manual states to have 1045 lbs on the back. How about yours? Well I think we use the same book?

 

[gladehound]

I'm not an engineer but I did take several years of physics in high school and college. Maybe the laws of gravity and deflection have changed since then.

Perhaps I've said it wrong.

The lift cylinder anchor point to the tractor is where the weight is actually lifted. The further back that lift point, the further back the weight is applied to the tractor. I incorrectly stated the pivot point of the loader.

With the skid steer, the pivot point is over the rear axle so the lift point of the cylinder can be further back so more weight can be supported by the rear axle (actually spread the weight more evenly over both axles by moving the weight to the rear).

If people say that is wrong, then it's a matter of semantics or you guys are all nuts!

After 150 round robbin posts, I have no doubt! We're ALL nuts! :laughing:

Some of us are right and nuts. Some are wrong and nuts! :laughing:

You are right that the lift cylinder pushes on the tractor. At the same time the lift arm pulls on the tractor. This creates a torque on the loader frame and tractor frame. This torque pushes the front axle into the ground and removes weight from the rear axle.

If you move the loader arms back, the same amount of torque would remove less weight from the rear and add less weight to the front compared to the loader arms being more forward, because the torque has to act on a longer lever arm to the front axle (pivot point).

However, if the load in the bucket is kept a constant distance in front of the front axle, it will affect unweighting of the rear axle and weighting of the front axle the same way regardless where the loader attaches to the machine. This is because moving the loader attachment back, adds and equal amount of length to the loader arms as it does to the distance from the loader mount to the front axle. The longer loader arms increase torque on the loader frame / machine frame given the same weight on the end of the loader. And these two factors (increased loader arm length and increase distance from lift point to front axle) cancel each other out. The weight change on the front axle is the same. Note: this example assume the loader itself has no weight. obviously it does, and for this reason having more of the loader closer to the rear axle will in and of itself change the weight distribution. But it will not change the effect that any weight added to the bucket has on weight transferred to the front axle (except that you will now be able to transfer more before you tip)

 

[4570Man]

I'm not an engineer but I did take several years of physics in high school and college. Maybe the laws of gravity and deflection have changed since then. Perhaps I've said it wrong. The lift cylinder anchor point to the tractor is where the weight is actually lifted. The further back that lift point, the further back the weight is applied to the tractor. I incorrectly stated the pivot point of the loader. With the skid steer, the pivot point is over the rear axle so the lift point of the cylinder can be further back so more weight can be supported by the rear axle (actually spread the weight more evenly over both axles by moving the weight to the rear). If people say that is wrong, then it's a matter of semantics or you guys are all nuts!

Why can you still tip a skid steer? The distance between the load and the front axle is the only thing that matters. My tractor loader mounts behind the front axel, but still lifts the rear axle when I put a load on the loader. I have a subframe mounted backhoe, but can still lift the front axle off the ground.

 

[ovrszd]

Okay, I can't stand it any longer. I'll take a stand on the skid steer example.

The loader arms on the skid steer must mount at the rear of such a compact machine to get arms long enough that it can raise the bucket to an acceptable height. If the length of the arms is mandatory and you hinged them at the front of the machine the bucket would be 5 feet farther forward from the machine. All practical design features would be lost.

With the SS bucket as close to the front tires as possible, and the hinge point as far rearward as possible, it can still stand on it's nose if the bucket is overloaded. Been there, done that many times.

I might as well dive in with both feet. There is a situation where adding rear ballast adds weight to the front tires rather than removing it........

 

[CalG]

oldpilgrim

Think about what you are saying objectively.

The typical tractor has two axles . ALL LOADS CARRIED BY THE TRACTOR ARE CARRIED ON THOSE TWO AXLES. regardless of where the lift points. pivot points, etc of the load supporting mechanism (FEL) are located. The tractor may as well be a solid beam with a single sliding weight on it. Move the weight anywhere on the beam and measure the weight on both axles.


Try to look at the example the same way that centers of gravity (CoG) are described. A LOCATION that is equal to ALL THE MASS were located (concentrated) in a single point.

Forces such as weight work the same way.

 

[gladehound]

I ain't ended up in Oz yet but you never know. My manual states to have 1045 lbs on the back. How about yours? Well I think we use the same book?

Mine says 1047 (because 1046 is too little and 1048 I too much) :laughing:

Despite the precision of listing the weight to the pound, they fail to give any recommendation on how far back the weigh is! And that makes me chuckle!

 

[jenkinsph]

4) The 'Math' behind all of this jaw boning would be taking Moments (force times distance) from any convenient single point in the side view and summing them up. Same analysis used to figure out where a previous threadster's trailer axle needed to be in order to reduce his tongue load. Yes, you need to include the tractor's wheel weights, center of gravity and total weight, loader content weight, ballast box weight and the distances from each point mass to the chosen central moment point. Then its just sophmore High School algebra.

I agree with this^^^^^^
While I have found this thread to be entertaining to read the above paragraph is the correct way to solve the problem. At least that was the way I was taught in structures class in school.

 

[ovrszd]

Mine says 1047 (because 1046 is too little and 1048 I too much) :laughing:

Despite the precision of listing the weight to the pound, they fail to give any recommendation on how far back the weigh is! And that makes me chuckle!

I can usually tell in the tractor seat when I've reached the magic number.

 

[CalG]

Okay, I can't stand it any longer. I'll take a stand on the skid steer example.


I might as well dive in with both feet. There is a situation where adding rear ballast adds weight to the front tires rather than removing it........

As covered in several previous posts, the rear counter weight can not add weight to the front axle, but it can add to the forces experienced by the front axle when a heavy weight is carried forward of the front axle. The example would be "lifting" a heavy object with the FEL while rear counter weights are in place. Ballisted tires or add on wheel weights will do the same. It's all been covered over and over. Weight behind the axle is just another case of the same thing.

There is really no front or back in these considerations. If the tractor were completely symmetrical with a CoG located at the midpoint between the two axles, loads at one end would be reacted at the other in exactly the same way. Vis a Vis ;-)


Might be a handi piece of equipment ;-)

 

[4570Man]

Mine says 1047 (because 1046 is too little and 1048 I too much) :laughing: Despite the precision of listing the weight to the pound, they fail to give any recommendation on how far back the weigh is! And that makes me chuckle!

Yeah. 1047 on the 3 point hitch won't provide nearly as much ballast at the end of a 8' boom pole.