Ballast How much ballast is too much?

[cttractor]

I like LD1's suggestion of a making the ballast box something like 75% of the load you can carry. Generally, the 3pt will lift more weight than the loader on all tractors I've seen and used. So it's easy to put much more weight on the back than we need. And while I do want to have less weight on the smaller front axle, I also don't want to reduce it so far as to rock on the rear axle. That's happened to me many times when I've had a large rock captured between the bucket and dipper of a backhoe. I want to keep it there to transport it, but as soon as I lift the outriggers, I find my front end leaving the ground unless I've had the foresight to preload it with gravel or some rocks before I started digging with the hoe. (And if I had the foresight to do so, I often find some of that front ballast dropping out as I keep repositioning the machine while I dig -- Murphy ALWAYS wins....)

 

[North Country]

If your back wheels are "just about to lift" there's something else you might think of, even if you're on perfectly level ground.

All the weight of your tractor + the weight in the bucket is sitting on the front axle. I don't care what make or model you have, it wasn't designed to carry that much weight on a regular basis.

 

[Baby Grand]

When I was out tractor shopping, my dealer told me that the heavy brush hog I had my heart set on would be too much weight (front would lift) for my tractor without the FEL, even with a full front weight set. He based this concern on sections of the owner's manual - which he copied and highlighted for me - he also highlighted the part where it says that using unapproved implements (heavier than they recommend) would invalidate the warranty.
In addition, he stated that he had been raised on a farm and used similar equipment since he was a child and had sold Kubotas for 20 years. All of this he sent to me in a letter that I still have. Having absolutely zero tractor experience myself, I thought "What the heck does he know?".

So I did a quick moment analysis on my tractor. It was a real swag (Scientific Wild Arse Guess). First guess was the location of the center of gravity of the tractor with no implements. I assumed that it would be 2/5 of the distance from the front axle to the rear axle. Then I estimated implement weight & CG and threw in torque about the rear axle in 1st gear at PTO speed. According to my calculations, the dealer was right.

My analysis didn't account for height of the CG and I never did that estimation. This is important when you talk about ballasting and operation on slopes. Where the ballast CG is located, vertically, is also important; obviously, you want it as low as possible. Additionally, you want it fixed, so that if'n you do start to tip it doesn't start to move on you. I have always been a bit distrustful of the brush hog as ballast on slopes for this reason - with the flex link on top it can pivot about the bottom pins a fair amount, raising the CG as it does. A utility box filled with cut wood (what I use) can also be a risk - if there's so much wood that it can shift position or some can drop off the top, that's not good. A moving CG is a snake in the grass.

-Jim

 

[cttractor]

If your back wheels are "just about to lift" there's something else you might think of, even if you're on perfectly level ground.

All the weight of your tractor + the weight in the bucket is sitting on the front axle. I don't care what make or model you have, it wasn't designed to carry that much weight on a regular basis.

You make a great point. I have to believe the front axle is designed to handle this. But that's still different than operating this way as a matter of course. This is one of those times when I'd love to be able to ask a designer of tractors this very question. The irony here is that there's no doubt that the manufacturers have one or more staff reading all of our posts all the time -- this is just too major a tractor forum to ignore and most large companies in fact do this. Still, I'm also positive they won't chime in because if they cooroberated that they read everything, we'd never stop asking questions.

 

[milkman636]

Tractor brakes are on the rear axle only. If there is not enough weight on the back end of the tractor to stick the rear tires, you are sacrificing the ability to brake on inclines or declines. If you lock the brake on a grade and your tires slide your back end is too light.

 

[North Country]

I have to believe the front axle is designed to handle this. But that's still different than operating this way as a matter of course.

I'm sure they consider it, but when I looked up the specs of several randomly selected utility tractors on JD's web site the published front axle capacity was never more than the shipping weight. Add the FEL and the bucket load, and you're well over "design weight." Of course all of use have done this at one time or another without snapping axles, but it's worth considering just how much load you're putting on there.

If you lock the brake on a grade and your tires slide your back end is too light.

And you need new shorts. It's a horrible time to find out you're not stopping.

 

[Turbys_1700]

I just purchased a Stoll FEL for my NH 1720...
The owners manual comes with a set of ballast recommendations...
I typically run a 550# box blade on the back of my tractor when using the FEL and it works out very good...
I try to keep the loader as low to the ground as possible and keep the FWA engaged...
Low center of gravity and deliberate speed is your friend...

A good rule of thumb is that the weight of your ballasted tractor should be 1.5 times the weight of your FEL and the weight it is carrying...

My tractor weighs around 3300# with loaded tires...
My box blade puts it at 3850#...
My FEL has a capacity of 1000# lift and the loader weighs 440# not counting the bucket...
I calculate my bucket @ 200#...
That gives my FEL totals @ 1000+440+200=1620# total...
My tractor is very stable with a full bucket of material...

 

[cttractor]

Tractor brakes are on the rear axle only. If there is not enough weight on the back end of the tractor to stick the rear tires, you are sacrificing the ability to brake on inclines or declines. If you lock the brake on a grade and your tires slide your back end is too light.

That's true when in 2WD; all four brake when in 4WD.

 

[cttractor]

Of course all of us have done this at one time or another without snapping axles, but it's worth considering just how much load you're putting on there.

And you need new shorts. It's a horrible time to find out you're not stopping.

I agree on both of your points

 

[nvpliers]

I know rear ballast counters the FEL load. But does rear ballast also help to prevent sideways tipping, when working sideways along a slope?