Ballast How much ballast is too much?

[cttractor]

I'd like to elicit some commentary about differences between adequate and extra weight placed on the rear of a tractor. Essentially, I'm wondering about whether or not it's possible to carry too much ballast on the rear. We all know that we want to have enough weight there so the rear tires don't leave the ground when we lift something with our loader. We also know we should keep the load as low as possible to keep a low center of gravity. But the question really is: do we need just a little more ballast than that required to counteract the loader and its payload when the relief valve kicks in? Or is there benefit to having even more weight there?

For example, does excess weight beyond that help keep us more stable on hills? If the former, we're better off reducing the weight in the rear to only what we need plus a little extra because additional really grinds and wears our lawns down when we drive across. If more weight than what's needed to counteract the maximum lift capacity up-front makes us more stable on inclines, then safety always trumps a lawn and we should run higher weight amounts.

It'd be great to have someone "weigh in" who's performed an analysis of the pertinent "moments" or could provide a URL to a related study. But a lot people on this site also have many years of experience operating tractors and heavy equipment on all sorts of surfaces and those experiences can be very enlightening.

I appreciate any insightful comments anyone might have to offer. Thanks much!

 

[TripleR]

If NEBRASKASPARKS doesn't show up, you might PM him or research his threads as he has done a lot of research on this and other subjects.

I have no real "formula" and add enough to the point to where it is stable when using the FEL. All the tractors I use in the hills have loaded tires plus weight on the 3PH of some sort.

 

[cttractor]

Thanks for the ino TripleR. I'll hope that NEBRASKASPARKS gets wind of this thread and jumps in.

I think that most of us do what you're doing in that we load the weight on in tires, ballast box, wheel weights, etc., because that's the advice we all get. When I'm running a bigger machine or a TLB, I try to avoid lawn areas as much as possible. and try to reduce driving on any grass where I'm not working. But I'm often using my CUT for lots of jobs over the lawn and am tiring of making a mess of it. If reducing ballast only to what I need gets the job done, doesn't make as much of a mess, and doesn't compromise safety, I'll go that root. But it was in thinking about this that I realized I knew less than I needed to make an intelligent decision. And I hate doing something stupid; it always hurts.

 

[TripleR]

"Just the right amount" is probably going to vary from one individual to the next. I don't get overly alarmed if a wheel lifts a bit backing out of a gravel pit, pond etc., with a full bucket, but some do. I am not recommending this, I just know my tractor well enough not to be alarmed.

For my conditions and uses, I would have to carry more weight on the back and or add wheel weights to keep my rear tires "always" rather than "mostly" in full contact with the ground and I really don't want to haul that much weight around all of the time.

I am old enough to realize about the only way I am going to avoid doing something stupid, is to stay in the house, but I would probably trip over something. While I can't totally avoid doing something stupid, I try to avoid doing something intentionally stupid and am always open to advice from others including members of this forum many of whom have been of enormous assistance in picking the right tractor, equipment and operating procedures.

I will be following this thread with interest.

 

[LD1]

Short answer is YES.

If you have "just" enough weight to make the loader go into relief, and IF AT THAT MOMENT, you have almost 0 weight on the rears, YES you need more weight. If not, any change in direction/incline/momentum will result in a tip-over.

How much more depends on how steep the inclines are and operator comfort.

BUT as a general rule, the more the better as long as you dont exceed the MFG's maximums for the 3PH. Because the more weight you add to the 3PH is more weight taken off the front axle. And the rear axle/tires are WAY stronger than the fronts.

Also, when talking stability, it isnt just the amount of weight out back, but also how far out back it is. The farther the weight is out back, the less is required to do the same as weight up close. That is why I like a good heavy blade or bushhog (if space permits) as opposed to a ballast box. A 500lb bushhog will keep you MUCH more stable than a 500lb box.

And for a reference, I have a L3400. With a 700lb rear blade, it IS possible to make the rears light if you are going down a steep grade and/or have to stop quickly when operating near the loaders MAX. I also have an ~1100lb bushhog. And while I will not say it is impossible, it is pretty near impossible to tip the tractor with that thing out back.:thumbsup:

I have also shimmed my PRV a tad to bump up the lift cap. I am running ~2600PSI as opposed to factory spec of ~2400. I have lifted and moved a 1400lb propane tank with the 700lb blade on the back. Allthough it hills or stops were involved it would be a bit scarry. Based on that, I'd say a 1:1.5 ratio would be about perfect. If you size your rear ballast @ 75% of the loaders lift capacity, that should cover about any scenerio you run across.

 

[cttractor]

You both make excellent points -- thank you! Being too near the balance point really does help only when you're on level ground. It would be no fun and quite frustrating to start tipping by hitting the unseen bump or dropping into the unseen pothole and realize a couple hundred extra pounds would have made the difference.

I, too, am interested in what other wisdom will be offered in this thread. Thanks both!

 

[Wolfy]

Much of it depends on the tractor. A 2wd loader needs more weight for traction. If that same loader has 4wd, it won't need as much weight. But they both need a minimum weight for stability. I have found on my 4wd Kubota, an overload of counterweight actually decreases traction, since there isn't enough weight on the front axle.

 

[LD1]

I have found on my 4wd Kubota, an overload of counterweight actually decreases traction, since there isn't enough weight on the front axle.

I have found just the opposite to be true in my experience. The front tires are tiny, they do little anyway. I want all the weight over the larger rear tires as I can. THAT is where the real traction is.

 

[RoyJackson]

Your tractor's manual should give you a guide for ballasting. Deere does....maybe other manufacturers too.
There's also considerable information on the Internet, if you want to spend a bit of time doing the research. It just depends on how in depth you want to get. Most of the information I've read was directed towards agricultural owners/operators.
No doubt a farmer wants just enough ballast for a given job, but not too much to prevent some tire slippage. And, of course, unnecessary weight reduces fuel economy (might not be much and pretty irrelevent to we CUT/residential owners...but when you work a couple thousand acres it adds up).

 

[Wolfy]

LD1, I seem to recall the L2800/L3400 used 7x16 front R-1s....the Kubota I mentioned has R-4s, however I also have a 4wd Ford close to a L3400 size. That tractor has 6x16 front R-1s. In that situation, you are right. Plenty of counterweight is needed. But my Ford and Kubota are two different animals. I guess that is true of most tractors.

 

[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?