Each has pro's and con's. In most compact tractors, the big advantage of fluid is that one can get more weight on the wheel. With JD tractors, the wheel weights are very expensive from the company and do not add all that much weight relative to the ballast that can be achieved with fluid. The drawback to fluid is that one is stuck with it all the time. My little 2320 has loaded rear tires and though great for loader work, snow removal, etc., the machine can compress delicate grass/lawn and the fluid cannot be taken on and off. In this case I would have probably been better choosing weights. Smaller tractors, like sub-compacts, have the opposite problem. The rim size, relative to the tire volume, generally means much more weight can be added to the wheel than to the tire. For example, on a JD 1026 with 26x12x12 tires (which are pretty small), the machine can hold about 50 pounds of ballast per tire but can be spec'd with up to 172 pounds of cast iron ballast as wheel weights per wheel (72 pound starter and two 50 pound add-on's). The opposite almost always holds true on larger tractors, except with R1 style tires. As for center of gravity (COG) there is little difference. Most places that ballast try to fill the tires as fully as they can to achieve maximum weight. This means that even with some air in the casing the tire is pretty full of fluid, usually passing the centerline of the axle easily. Wheel weight v fluid both add stress to the axle. Most companies consider this when designing their machines because they know most folks are going to need to ballast. Also, the axle stress from this is much less likely to be harmful than having excess slippage and the stresses associated with that. There also is the consideration that in most compact applications the amount of on-wheel ballast recommended by the manufacturers exceeds what can be specified with EITHER liquid or cast iron weight, so one could argue many of us need to be running both to meet factory recommendations. All this said, my general advice has been: for small sub-compacts or compacts less than 25 HP with smaller tires/wheels one can almost always add more ballast with cast iron than fluid. For all other compacts, the opposite is more likely true (but I realize not always). Unless one has a specific need to remove the weight (finish mowing a delicate lawn, large time periods of non load-bearing tasks on pavement or concrete), or in an instance where an attachment offers significant ballast (compact with a back hoe for example), I recommend liquid ballast. In those other unique applications, one would probably want to consider removable ballast unless it is cost prohibitive. I like Rimguard. From an environmental standpoint it makes sense, but from a practical standpoint it does as well as it is very heavy and has a high solute.
John M.
