Speaking of tilt...

[scruffy]

Only if you make the engine grunt Harv, like the 'poor little guy' pulling your name!
Hey, ebay has a few Kubota's listed. One is a 2900 with 500 hours, lots of implements for 6500 + 1000 for the implements...posted a message about it under Kubota buying. (Kubota 2900) Looked nice. Don't know if the price is reasonable...seemed like it.

[TomG]

Too much weight? Tires do have a load rating. More ballast probably means less 3ph capacity, or at least a need to run higher tire pressures. More ballast also means more soil compaction, more fuel, more tire wear (especially on pavement), and a rougher ride. There are disadvantages to carrying ballast.

Somebody mentioned tire tread prints awhile back for determining appropriate tire pressures. The idea is to drive across fairly dry soft soil and then look at the tread prints. I don't remember all the details, but the idea is to see clear well defined bars clear across the tire width. Too much tire pressure and the ends of the bars fade out. Too little and the centres fade. The idea may work for tread patterns other than ag.

The reason for checking tire prints is that a particular tire profile on the ground gives the best traction. Too much pressure or too little and the tires lose traction. So I guess the idea is that there is too much weight if the tire pressures are at max rating and the tread print isn't good.

I mention the traction thing, because I think traction is maybe more important than stability, especially for going straight up and down slopes. I usually think of ballast as being added to increase traction or as a counter-weight. I guess adding weight below the CG does increase stability, but I'm wondering about the effectiveness of using wheel-weight ballast for stability.

My impression is that wheel weights are still a fairly small percentage of the total tractor weight. I'm not sure where a typical CG on a tractor is located, but I suspect wheel weights are carried not much below the CG anyway. I'd keep in mind that with wheel weights, half the weight is carried above the axles. I guess I'm sitting here wondering if any amount of weight that's feasible to hang on a tractor would actually turn an unsafe slope into a reasonably safe one.

[wen]

TomG,

I have 1400 pounds of ballast in the tires with a total weight of about 7500#. Allow 1000# for my boxblade and 2000# for load in the bucket and it still sets at a lighweight 10,500#. The footprint is more apt to be a function of the sq inches of contact area of your tires rather than dependent on the weight of the tractor. Steel is used for weights because it costs less and is not a hazardous item for manufacturers to fool with and dispose of. Wheel weights add weight below the CG and ballast in tires is lower than the CG. Both are very good. Traction is the name of the game and you can't have too much. There is a reason why it takes an 18 wheeler to haul the tracked vehicles.

Tire pressure is set in the front by the load and is probably about maximum to accomidate a loader. Rear tires will always carry much more weight than the tractor because the large footprint is desired for traction. They should be run at the minimum pressure to carry the load. Ag tires are always going to sink fully into tilled or plowed soft ground to get their traction.

[MChalkley]

Wen - "Traction is the name of the game and you can't have too much." Well said, but don't you remember the guys who challenged me when I said that? [img]/w3tcompact/icons/laugh.gif[/img]

Nevertheless, I remain firmly entrenched in my (and your) original position: You can't have too much traction.

Mark "What are the symptoms of too much traction? [img]/w3tcompact/icons/wink.gif[/img]" C

[DONOTDELETE]

I thought we covered this! [img]/w3tcompact/icons/wink.gif[/img]

The main symptom of too much traction is the days becoming longer or shorter due to spinning the earth faster (or slower).

[TomG]

Don't know. I guess my attitude is that you need enough traction to get a job done and done safely. Carrying more weight than necessary adds to wear and tear and soil compaction etc.. Wear and tear may be accepted because it's hard to tell how much ballast is needed for safety, or because it isn't convenient to keep changing ballast all the time. However, it's hard for me to ignore that it's there. Carrying a lot of weight seems like it's harder on a tractor than not carrying so much.

The guy's point in the tread print comment I passed along is that load distorts tire profiles, and that affects traction. It's probably a small point in practical terms, but may be interesting never the less. The point made is that there is a correct pressure for a given load. There's probably a load/pressure table in everybody's owner's manual. From another comment, I guess I should conclude that tires don't have weight ratings, and weight can just be piled on without any consideration at all.

I wish my main point had been addressed. I'm looking at a slope I think is marginally unsafe (noting that soil condition has a lot to do with safety). I really don't know how much more confidence I should have in the slope if I put a bunch of extra weight on the tractor. That's worth thinking about I think. If I accepted the ballast idea without qualification, I might think that any problem could be mastered just by adding more weight. I'm not sure that's a good idea for a novice, like myself, to take away from all this.

[PaulB]

I am a complete novice as anybody who frequents this board well knows, but I do believe that ballast WILL allow just about anything. Case in point is the highway guys I see mowing the sides of the road. These guys must have special tractors, because they go sideways on slopes I wouldn't even consider going up or down. Only thing I can figure is they have real heavy mowers mounted real low, so the CG must ride a half an inch off the ground. I think Rick at R&B actually did this for a living, so maybe he can comment?

[DVerbarg]

Mark C,

One symptom of "too much traction" is the engine dying while under load. Consider an example of using a loader, if we have too much traction while pushing into a pile instead of the wheels starting to spin when nearing the capacity of the tractor the engine will stall. This same issue can occur when pulling implements (or trees, rocks, etc).

This has come from my personal experience having used a couple different tractors. Having said that, some tractors need additional weight due to soil differences, tire lug differences, or tractor engineering differences.

DavidV

[wen]

TomG,

Most ballast on tractors is in the tires. It does not affect the bearings, axles or any other parts of the tractor. It does help both traction and stability. 4WD with all the ballast you can get on a tractor is the second best thing to a tracked vehicle, which is the best thing - and I wish I could afford one when I need it (like right now).

Yes, tractor tires have load limits, but the rear tires are usually only used at a fraction of these limits due to their large size, that is why the tire pressures can be run so low.

Traction and Stability are both required at all times. One is kinda meaningless without the other.

There is no downside to too much traction. If you can kill the engine, you don't have enough engine.

I would expect to fill the bucket completely or push through the pile. Nearly all Ag tractors have draft controls to limit the load while pulling earth engaging 3 point loads to the point the tires won't slip.

If you want good examples, look at the Kubota M9200 Orchard tractors. They drop the wheel diameter from 30 to 24 inch and use solid steel inserts in the wheels to lower the cg. Yes, wheel weights are considerably below the cg on most tractors. Ballast in the tires is below wheel weights due to most of the water being in the bottom half of the tire.

As far as ballast as a function of tractor weight, A M6800 is 4500#, 1500# loader, 1400# ballast in tires plus driver and fuel drives out at nearly 8000#.

[gerard]

wen,
If you load the tires do you have to use tubes?? Plugging a tire is pretty simple if you pick up a nail. I couldn't do this if I had a tubed tire. If I use antifreeze and no tube does this have a corrosive effect on the steel rim or does the antifreeze component take care of this? I'm going back and forth on loading vs making up some wheel weights.