Theory of rear ballast?

[jodebg]

I need to build a rear ballast box for my Kubota B7800 with FEL.

I have a couple of questions as to how to do this.

First, should the ballast weight be upright in design and the weight
centered on the tractor?

Or, is it better to build a horizontal ballast and spread the weight left and right?
If so, relative to the rear tires, how far out should the ballast go?

Should I keep the ballast box as close as possible to the tractor?

How much weight would be ideal for this Kubota model?
FEL lift capacity is around 780 lbs.

I should add that I am also thinking about filling the rear tires.
Do I need to take that additiional liquid weight in the tires into consideration?

Thanks.

 

[dragoneggs]

Okay I will start here. Spreading the weight out side to side does nothing for you. It's all about CG (center of gravity). Personally I am not a fan of a ballast box that has no function other that to act as a counterweight but if a rear implement doesn't offer you something... okay fine. Building the ballast box such that the CG is in the center (side to side) and as low as possible would be my goal. As far a filling the rears... if you are going to go with a rear ballast, IMO you are wasting your time with filling the tires. The more rearward load of the ballast will be much more effective than the filling of the tires. Again, speaking from a CG point of view which is most important when talking weight, counterweight for FEL, traction, etc.

 

[davesl708]

First, should the ballast weight be upright in design and the weight
centered on the tractor?

The weight should be centered. Lower to the ground is better for stability.

Should I keep the ballast box as close as possible to the tractor?

The farther back the greater the leverage and less weight you would need. However the farther back the more room you need to maneuver.

How much weight would be ideal for this Kubota model? FEL lift capacity is around 780 lbs.

Since you are only dealing with 780lbs. lift. filling the tires may be enough. Question is do you want the tires filled all the time or do you have occasions where the extra weight would not be practical. The rear ballast gives you options.
You should not need more than a couple hundred pounds to keep it stable.

 

[s219]

I'd fill the rear tires and consider that ballast only there to help offset the permanent weight of the front loader. And then the added ballast, in the form of a weight or a rear implement like a box blade, is there to offset the weight of what you carry in the front loader.

Personally, I'd want to make the ballast box as compact as possible to maintain maneuverability. I'd size it and the mounting hardware based on guidance from an existing implement you have that is known to fit and not interfere with anything when hanging on the 3-pt (it's certainly possible for an implement to be too close in, so you want to make sure there is enough breathing room).

As the main point of the ballast is to offset front loader payload, I'd keep it tight/narrow sideways so that you are not compromising lateral stability (i.e., the wider you make it, the more it could compromise lateral stability on an incline, so keep it narrow). The farther out behind the tractor it is, the more "lever" it can create to oppose the front payload, but at some point it would stick out too far and hurt maneuverability, or possibly be a detriment when there is no payload in front. So again, I come back to the idea of making it compact and approximately laid out like the 3-pt mounting arrangement of an implement, maybe a little closer in.

 

[jeff9366]

I need to build a rear ballast box for my Kubota B7800 with FEL.

I should add that I am also thinking about filling the rear tires.

Do I need to take that additiional liquid weight in the tires into consideration?

Ballast Box OR loaded tires; not both for a B7800.

Loaded tires are ballast; loaded tires are not counterbalance. The Ballast Box or an implement carried on the Three Point Hitch will be more versatile. Weight behind the rear axle (counterbalance) unloads stress from tractor front axle and bearings.

I normally use my 630 pound Box Blade as counterbalance on the Three Point Hitch, this is nominally 36% of FEL LA805 lift of 1,715 pounds, but since Box Blade is cantilevered to the rear the effective counterbalance is greater than 630 pounds, probably 900 pounds effective. This has never proved inadequate.

When maneuverability is important I mount my 650 pound Cultipacker on the Three Point Hitch. The Cultipacker rides very close to the rear of the tractor.

Photos #1-#3 Rollover Box Blade as ballast.

Photo #4 Cultipacker as ballast.

 

[k0ua]

I have both loaded tires and a ballast box. Both help, and sometimes in different ways. Remember you are not always going to have the ballast box on. For instance pulling my rear blade loaded up with snow or dirt, The rear loaded tires are helping me maintain traction to pull that load. The ballast box is back at the barn. When operating my loader with full loads of stone up front, I am glad I have the ballast box to help unload the front axle, and the loaded tires are helping to keep them planted on the ground too, even if they are not helping unload that front axle.

When I am mowing on a side-hill, the loaded tires are helping me with lowering my CG for stability, and again the ballast box is back at the barn. My ballast is a 55 gal concrete filled drum but about 10 inches of space at the top for carrying things.

Would a square box that was wider at the bottom be better? yes probably. It would keep the CG even lower. Of course too wide and you have to start worrying about swinging into things, also too far back, while that helps with leverage, you also have to start worrying about hitting things. You decide how wide and how far back. It is a trade-off.

 

[vtsnowedin]

The owners manual for your loader should have recommendations for you. Mine recommends filled rear tires and 2000lbs on the 3 point hitch when doing heavy loader work such as stone or manure.
Having the loaded tires is handy as it is out of the way and always with you and balances out the weight of the loader arms and bucket. Also they aid traction when pulling a tool that is on the ground and not pressing down on draw bar or the 3PH. They also aid in stability as the fluid is mostly below the axle and helps lower your center of gravity. With just the filled rears I'm not afraid to do a bucket or two now and then or lift a log when needed but if I was going to bail manure all day I'd certainly want to load up the 3PH. I'm going to get another plastic barrel and stick a TSC cross bar in it and fill it 3/4 full of concrete and rocks. I'm going to see if I can set my draw bar out enough to rest the barrel on when in use so as to not constantly stress the seals.

 

[JerryK]

A ballast on the 3pt takes load off your front axle and adds rear traction, whilst filling the tires mainly just adds weight for rear traction. For heavy loader work, rear ballast is better on your front axle. But each has drawbacks. Loaded tires allow you to put something lighter on the rear to use, or work without anything back there to maneuver in tighter spaces. But you always have that weight with you, can't drop it off. Extra weight to haul if you trailer. Ballast takes up your 3pt and sticks out some, so you have to allow for it back there in close spots. So, not a good answer either way. I'm a ballast guy, and have not filled my tires. But to each his own.... Here's a one ton I made.... [ 99% of the time my ballast is 1500#'s of American made backhoe ]

 

[k0ua]

A ballast on the 3pt takes load off your front axle and adds rear traction, whilst filling the tires mainly just adds weight for rear traction. For heavy loader work, rear ballast is better on your front axle. But each has drawbacks. Loaded tires allow you to put something lighter on the rear to use, or work without anything back there to maneuver in tighter spaces. But you always have that weight with you, can't drop it off. Extra weight to haul if you trailer. Ballast takes up your 3pt and sticks out some, so you have to allow for it back there in close spots. So, not a good answer either way. I'm a ballast guy, and have not filled my tires. But to each his own.... Here's a one ton I made....

That looks really nice Jerry.

 

[jodebg]

Looks great. What is the weight of 1 cf of dry concrete? How did you chamfer the corners?

A ballast on the 3pt takes load off your front axle and adds rear traction, whilst filling the tires mainly just adds weight for rear traction. For heavy loader work, rear ballast is better on your front axle. But each has drawbacks. Loaded tires allow you to put something lighter on the rear to use, or work without anything back there to maneuver in tighter spaces. But you always have that weight with you, can't drop it off. Extra weight to haul if you trailer. Ballast takes up your 3pt and sticks out some, so you have to allow for it back there in close spots. So, not a good answer either way. I'm a ballast guy, and have not filled my tires. But to each his own.... Here's a one ton I made.... [ 99% of the time my ballast is 1500#'s of American made backhoe ]