Ballast Weights - How much is too much?

[rjkobbeman]

Well, if rear ballast did not take weight off of the front axle then how does putting too much weight in the FEL take weight off of the rear axle?

It's the same thing...

Everyone is on-board with putting weight on the rear end too keep the rear end from coming off of the ground when putting weight in the FEL. But for some reason, the idea of putting weight in a ballast box behind the rear axle (think Rear End Loader) to take weight off of the front axle escapes some.

Pretend the front of the tractor is the rear and the rear of the tractor is the front. Now pretend a ballast box is the FEL.

 

[frogfish]

This is what's referred to as a lever (simple machine), When you put the ballast in the rear, the rear axle is the fulcrum to lift the front, when the load is in the FEL, the front axle is the fulcrum. I think people are getting confused because there are two fulcrum points and depending where the load is and the distance from the fulcrum will determine which end goes up or down.

Bottom line is: if you add weight to the rear, this WILL take weight off the front axles because the rear axle is the fulcrum. Enough weight in the rear and the front will come up. The same is true in the front, enough weight in the FEL the rear axle will come up but the front axle is bearing the weight because it it the fulcrum in this case.

So adding weight in the rear will lessen the load on the front axle.

I'm not an engineer, but I have played on the teeter-totter as a child and it it the same principle.

 

[mattellis2]

heh. turns out that i am one of those nerdy engineer types, and i agree rjkobbeman. you're just summing moments about certain points. wheel weights and loaded tires are not as efficient since when computing their resistive moments, you're summing around the front axle. the ballast weight hanging on the end of the 3 point has a moment arm 3-4' longer than a wheel weights mounted on your lugs, so you get more bang for your buck.

"taking weight of the front axle" is the result of moment applied around the rear axles. the FEL applies a positive moment, and the ballast weight provides a negative moment. these forces cancel one another. if the negative moment applied by the ballast box is larger than the positive moment applied by the FEL, the front end wants to rotate around the rear axle...the wheelie mentioned elsewhere. the key is to keep everything moderately balanced.

-matt

 

[dynasim]

Ballast of that size should not be allowed to sway, for a variety of reasons.

If you set a hammer on your leg, it doesn't hurt. If you take a swing at it, it will. On my NH TC45, the sway limiters will not take impulse(hammer swing) loads.

You could either tighten up your sway limiters, or move the bars in closer such that the arms rub firmly on the friction plates. On our farm, we did the latter. The key is to not let the weight swing.

This is also likely to help with stability on hill sides. It is my experience that it is changes in direction that causes tipping(though I have never tipped a tractor. A truck, but never a tractor). Having ballast that can move side to side can only be bad.

Chris

 

[Baby Grand]

Ballast aft of the rear axle unloads the front axle.
It's physics, not speculation.
To demonstrate - try taking your FEL off and maxing out your 3PH - your front axle will become completely unloaded and your front wheels will lift off the ground. Now let's have no more of this nonsense. Harrumph!
-Jim

 

[bp fick]

Well, if rear ballast did not take weight off of the front axle then how does putting too much weight in the FEL take weight off of the rear axle?

It's the same thing...

Everyone is on-board with putting weight on the rear end too keep the rear end from coming off of the ground when putting weight in the FEL. But for some reason, the idea of putting weight in a ballast box behind the rear axle (think Rear End Loader) to take weight off of the front axle escapes some.

Pretend the front of the tractor is the rear and the rear of the tractor is the front. Now pretend a ballast box is the FEL.

This is what's referred to as a lever (simple machine), When you put the ballast in the rear, the rear axle is the fulcrum to lift the front, when the load is in the FEL, the front axle is the fulcrum. I think people are getting confused because there are two fulcrum points and depending where the load is and the distance from the fulcrum will determine which end goes up or down.

Bottom line is: if you add weight to the rear, this WILL take weight off the front axles because the rear axle is the fulcrum. Enough weight in the rear and the front will come up. The same is true in the front, enough weight in the FEL the rear axle will come up but the front axle is bearing the weight because it it the fulcrum in this case.

So adding weight in the rear will lessen the load on the front axle.

I'm not an engineer, but I have played on the teeter-totter as a child and it it the same principle.

heh. turns out that i am one of those nerdy engineer types, and i agree rjkobbeman. you're just summing moments about certain points. wheel weights and loaded tires are not as efficient since when computing their resistive moments, you're summing around the front axle. the ballast weight hanging on the end of the 3 point has a moment arm 3-4' longer than a wheel weights mounted on your lugs, so you get more bang for your buck.

"taking weight of the front axle" is the result of moment applied around the rear axles. the FEL applies a positive moment, and the ballast weight provides a negative moment. these forces cancel one another. if the negative moment applied by the ballast box is larger than the positive moment applied by the FEL, the front end wants to rotate around the rear axle...the wheelie mentioned elsewhere. the key is to keep everything moderately balanced.

-matt

Three well written summations of the teeter totter principle. Thank you all gentlemen. Wheel weighting does not take weight off the front axle, but rear ballast does.

 

[Ford tractor]

I don't think adding rear weight reduces the load on the front axle.

The total weight increases so that some remains on the rear, but the front axle load doesn't decrease.

I would give a detailed answer, but there seems to be a lot of experts that have already done a better job than I could have.

 

[jenkinsph]

I agree that using a 1250 lb weight on the rear hitch will reduce the weight on the front axle.

If you were to consider the weight is centered 5' behind the rear axle and considered this to be a counterclockwise force of 5' x 1250 lbs= 6250 ft lbs and the tractor has a 6' wheel base as mine does this would provide 6250/6'=1041.6 lbs of lift to the front axle.

I also agree not to allow sway and movement of the hitch, this will wear and tear and beat the tractor up.