Basic Tractor Ballast for Dummies - instructors needed....Volunteers?

johnrex62 · Jun 23, 2012

I would like to learn the basics of ballasting a tractor. What to look for, how to calculate, etcs......

I have an Kubota L3700SU. My mower weighs 480lbs and the fel weighs 895lbs. I am not sure if the fel weight includes the bucket or not, the brochure does not specify a bucket weight. I am sure the fel is more than enough ballast for the mower, but is the mower enough ballast for the fel if I am moving clay soil?

If I attempt other implements, how do I determine adequate ballast? How do I ensure I am not over ballasted? Please consider me illiterate in this regard and don't overlook the basic theory and try to make it as specific to the L3700 as possible. :ashamed:

k0ua · Jun 23, 2012

johnrex62 said:
I would like to learn the basics of ballasting a tractor. What to look for, how to calculate, etcs......

I have an Kubota L3700SU. My mower weighs 480lbs and the fel weighs 895lbs. I am not sure if the fel weight includes the bucket or not, the brochure does not specify a bucket weight. I am sure the fel is more than enough ballast for the mower, but is the mower enough ballast for the fel if I am moving clay soil?

If I attempt other implements, how do I determine adequate ballast? How do I ensure I am not over ballasted? Please consider me illiterate in this regard and don't overlook the basic theory and try to make it as specific to the L3700 as possible. :ashamed:

I cannot go into theory with you, but I can talk experience with same tractor (L3400HST) you need approximately 300 more lbs. and loaded tires to make that tractor play nice. Now the mower sticks further out back, than my 750 lb ballast barrel, and that will help quite a bit. I had loaded tires with the 750 lb barrel and that seemed about right to me. When you load up a full heaping bucket of gravel and you are on slight slopes if if feels scary, (like a non ballasted tractor does) then you could use some more. I know this is not very scientific, but my gut tells me you need loaded tires (maybe you already have that?) and a little more than the mower, because my mower (I think it 450 lbs) was not enough.

James K0UA

Bluegill2 · Jun 23, 2012

What James said...

I have loaded tires on my L3800 and use a 500 lb+/- box blade, which is not quite enough. I'm going to add another 200 lbs to the box soon.

radioman · Jun 25, 2012

all I can say is liquid ballast in tires shouldnt be more then 75% or not more then top of your rims. If you turn stem so its upright at 12 o clock, you shouldnt get a spray of fluid coming out when pressing air core. at 11/1 depending on where stem is on rim you might or might not get fluid spray out. If you are filling your own tires, just a quick google of liquid ballast tires will give you some handy charts to compare to you tire size on how many gallons to put in and final liquid weight.

With my kubota- the weight of everything on my tractor was not all in one place in my manuals- but I was able to piece most of weight info from manuals and brochures to get total weight of my tractor. you just need to piece together info for your tractor.

As for being over ballasted - I just don't see how unless you know you will be working in SOFT sinking soil. In this case any weight is a bad thing. Same with tires filled with correct psi. Just lowering 5-10 psi will help immensely in floating on soft soils.
Have you tried digging in clay soil without ANY ballast just for giggles to understand your tractor behavior and then add on the weight you think you need and go from there? I really think this is the first step as you need to know the in/outs of your tractor in your particular soil. Just remember, the more your tires are spinning/but not filling the tire lugs with dirt means you need more "ballast" so you can "push more/deeper in clay soils". But you might be doing it wrong if you doing it all the time.You wouldnt want to bend anything. start small bites and then go to larger ones.

Leejohn · Jun 25, 2012

The way I tell is when the bucket is full, back up a little and take it out of 4wd. If the rear tire even want to spin I add more weight. I do this on flat ground and if I'm going to be on uneven ground I add just a little more. When on flat ground the tractor should be able to use the loader with out being in 4wd and if it does then you have the right weight on. That way you tractor is not a front wheel drive, the rears should be able to do about 90% of the work and the fronts just a helper. I do use 4wd all the time when using the loader it just fells better.

Bluegill2 · Jun 25, 2012

Leejohn said:
The way I tell is when the bucket is full, back up a little and take it out of 4wd. If the rear tire even want to spin I add more weight. I do this on flat ground and if I'm going to be on uneven ground I add just a little more. When on flat ground the tractor should be able to use the loader with out being in 4wd and if it does then you have the right weight on. That way you tractor is not a front wheel drive, the rears should be able to do about 90% of the work and the fronts just a helper. I do use 4wd all the time when using the loader it just fells better.

Right, even though we have 4wd, we want more weight on the back tires than the front and want the backs doing most of the pulling.

Rear ballast hanging off the 3pt hitch takes weight off the front axle and puts it on the rear axle.

EE_Bota · Jun 25, 2012

I look at the bucket/boom as a long wrench. I look at what is hanging off the back as a long wrench. If a fellow wants his rear ballast tucked up close to the tractor, it has to be far heavier than if it hangs way out the back. My little bush hog is my best ballast, and it hangs way off the back. If my carryall is on, it is puny ballast, unless I put a pallet on, and strap concrete block to the very back..at which point it becomes very serious ballast.

Try to keep your ballast low, and try to keep it from swinging side to side. Great ballast sticks out about as far from the rear axle as the bucket is from the front axle. A man really should read his manual for their recs.

Very serious ballast can relieve the front wheels of some of the weight of the loader. Imagine the Jolly Green Giant pressing down on the lift arms until the front wheels come off the ground..."HO Ho ho." It is pretty clear that some amount of down force in the rear will relieve the front wheels of some of the weight. I think it is pretty easy to make it easy on the front for an empty bucket, but harder with a full bucket. Wheel ballast has no impact on relieving the front wheels, only the ballast hanging off the back can do that.

I'm no expert (not even on giants,) but your manual should be written by an expert, and if you have doubts, point them out here, and someone will chew on them, but otherwise, if the manual recs seem reasonable, go by those recs.

I think it is important to know that your FEL pressure settings are supposed to be, and important that you don't exceed them. Proper ballast per the manual is based on proper pressure settings of the FEL.

Bluegill2 · Jun 25, 2012

My brother had our L3750 down in a hole with a loader full of gravel and no ballast on the rear. As he was backing out, he heard a POP in the front end and lost front wheel drive. Most of the tractor weight and all the bucket weight was on the front end and the rear tires had no traction.

When we tore it apart, the splines on the pinion gear, where the drive shaft coupler attaches were shared off. Further inspection we found most of the front end was worn out, likely from years of use with no rear ballast and lots of loader work. When the dust settled we were into parts for $1200 and 4-5 days of work.

Tractor is 28 years old, so I guess we can't complain too much. But if proper ballast would have been used all these years, I bet we would have never had this problem... Still a very good rig though!