Surprised by need for rear ballast with L 4060 in this situation

[Red Eye]

I built a ballast box loaded with steel, 1500lb. Perfect setup. I can use a grapple moving big logs, no problem. It stays on the tractor nearly all the time.

 

[Hermio]

I recently bought an L4060. I have a 4000 lbs SS QA fork attachment that I used with the L48 TLB that I sold before buying the L4060. I know it’s heavier than what one might normally buy for that size tractor, but I had it already. I have some units of hardwood lumber that I have moved around with the L4060, that are about 32” wide and 12’-16’ long, some of which weigh 1400-1500 lbs. I have beet juice in the tires for ballast. I was able to move that lumber around with no problem, while working slowly and carefully as I moved it.

Anyway, today I bought 25 leftover 4x8 sheets of 1/2” OSB from a guy and he brought them to me. We unloaded them from his pickup and put them on the forks of my tractor so I could move them to a different place on my property. These 25 sheets weigh 48 lbs. each, for a total of 1200 lbs. I had no problem lifting the 25 sheets, but my rear wheels were so light that they spun on my gravel drive.

My old L48 was my first tractor, and I always had the backhoe on it, and I never had a problem lifting anything with the FEL, and it spoiled me in that regard. I’ve been reading the many cautionary tales on TBN of hairy situations with rear wheels lifting off the ground, so when I have been moving my piles of lumber around, I’ve been very careful, and had no problems. But I was completely taken by surprise today when I couldn’t move with only 1200 lbs plus the fork weight because I didn’t have adequate ballast. Of course, OSB is 48” wide as opposed to the 32” widths of the lumber piles I’d been moving. I don’t remember my physics lessons.....is there an exponential increase in the leverage exerted as the load gets wider and further away from the fulcrum of the front wheels? Is there a simple math formula that would help me with anticipating when I have too much weight, based on the projection of the load? Thanks.

No magic math. It is a simple lever formula. The torque or moment is equal to the weight times its center of gravity distance from the fulcrum, which is the front axle. The CG must include the loader assembly as well as the lifted load. The counter torque is the weight of the rest of the tractor times its cg distance from the front axle. But since I doubt you know the cg, just add enough ballast so that your rear wheels stay down.

 

[NCL4701]

I’m going to have to stop reading this. All this talk of axle loading/unloading and weight transfer is starting to trigger the mild PTSD I have from Dr. Osgood’s Statics class I was in 30+ years ago.

If the rear of your tractor is too light when lifting something your loader will lift, add weight to the rear of the tractor. Something heavy on the 3 point is really helpful.

I don’t know about every tractor everywhere but I’ve found the Kubota L series to be rather light weight in comparison to their HP and loader capacity. Gives you flexibility but with that comes some responsibility. If you want a light weight tractor with a good bit of HP to pull a big mower you can do that with unloaded tires and no loader or loader removed. If you need a heavier tractor for pulling stuff or loader work, you can load the rears, add cast iron wheel weights, and/or put something really heavy on the 3 point in whatever combination to produce the performance and flexibility required.

You can take a bunch of measurements and calculate away, which may work if you are lifting known weights on level ground. If you have estimated weights (such as grappling logs or moving big rocks) and/or sloped ground (which is more typical) the calculations start getting complicated. Probably more practical to just add weight to the rear if the rear gets light when you’re doing whatever it is you’re doing.

 

[k0ua]

just add enough ballast so that your rear wheels stay down

You can take a bunch of measurements and calculate away, which may work if you are lifting known weights on level ground. If you have estimated weights (such as grappling logs or moving big rocks) and/or sloped ground (which is more typical) the calculations start getting complicated. Probably more practical to just add weight to the rear if the rear gets light when you’re doing whatever it is you’re doing.

Pretty much what I said up early in the thread. Just add some proper ballast. Don't do heavy lifts without proper ballast. It is that simple.

 

[Doug62]

Bushhog with a few sandbags on it makes a great ballast. The sandbags being that far back add much more ballast weight than their actual weight.

 

[varmint]

When I needed some rear weight, and didn't especially want anything swinging around back there, I built a ballast box out of 2 x 2 x1/4" angle, used some 3/4" treated plywood for the sides and bottom, and filled it with heavy rip rap stones. If I need to, it's easy to remove stones. I figure it weighs about 600 lbs plus another 75 lbs for the chains hanging on racks on each side, which is enough for my L3400. It has a trailer hitch on the back.

 

[Buggs67]

I did a small scale test with a toy loader thar actually proved this theory correct. The empty loader weighed 490 grams so I decided five bullets with a combined weight of 135 grams was a proportionally pretty good counter weight. For the first test I removed the loader ( the loader attachment from the loader ) zeroed the scale and dropped the counter weight in the back. It lightened the axel by 64 grams. Then I put the loader back on and then repeated the test. It lightened the axel by 63 grams. Then I put 5 bullets in the loader bucket and repeated the test. This time it lightened it 67 grams. Such small differences was probably caused by inaccuracies in the scale or stacking the counter weight in the box a little differently. But that’s only a difference of 1/11 of the total weight. 1/11th probably isn’t going to make the difference in busting the axel or not. View attachment 708914

This is too funny for words.

.45-70, you are one funny dude. And is that YOU'RE CAT or did you borrow it from the grandson?

 

[PCABE5]

After going through this thread, I get the feeling that maybe those who believe that 3 pt ballast won't alleviate the front axle, are using tractors with just a single axle, the rear one. In that case, yes, the front axle is irrelevant because it's not there.

Well I suffered through the whole thread and at the end I am left with the same impression along with that no one has ever ballasted an ag tractor and watched how weight moves front to back or back to front.

But nobody cares about the front axel weight without a loader.

Really? Big ag does it all the time especially when it comes to field work.

Just for example, hang a 95lb weight on a 9000 series JD and the front axle just saw 150lb increase. 95lbs from the weight and 55lbs removed from the rear axle to the front. So what is that a 58% increase over just the 95lbs.

 

[dbilling]

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regarding tipping force of your FEL loads, you're basically operating a lever where the pivot point is at (the bottom of) your front tires. if you add a load of 1000 lbs with a center of gravity 40 inches in front of front tires, that's the same tipping force of adding 2000 lbs with a center of gravity 20 inches in front of the front tires.

 

[sea2summit]

So boredom over lunch got me.

So if we have a wheel that weighed one pound and a weight that weighed one pound it would look like this. This is assuming we're using a 3' long board as referenced by 4570 and the one pound load is one foot from the one pound wheel.

If we apply gravity to this we get a tip over of our "tractor" because it can't hold the weight. Gravity causes force to be applied down with our weight (orange arrow) and our loaded tire for a total ground pressure of two pounds, one pound from our load coming in contact with the ground and one pound from our loaded tire.

If we decide to add counterbalance in the form of a one pound loaded tire one foot farther from the load we apply three more forces to our "tractor". On pound pulling down from our counter balance tire (blue arrow), this applies one pound of upward force on the weight (blue arrow), in tern the one pound load applies a one pound upward force on our ballast tire (orange arrow). At this point both the weight and the ballast tire are balanced applying no force up or down. So unless some other force is applied the entire load is not placed on our initial tire for three pounds of ground force all at the tire, even if we leveled out this contraption so the second tire was touching the ground it would essentially weigh nothing.

If we decide we want some weight on the second tire we can apply a second one pound weight to the opposite end of our "tractor" a further foot away from the load and past the second tire. This weight applies one pound of downward force of one pound (red arrow) which lifts one pound from the front axle (red arrow), at the same time the first tire is pulling down against that lift with one pound of force (green arrow) which also applies one pound of force upward on the new weight (green arrow). So now the total ground pressure is four pounds but each tire is only holding two pounds, that's a weight reduction on the front axle of one pound.

Would sure be nice if tractors had such easy numbers to play with