I know about putting liquid in the rear tires. Do people put liquid in the front ones? Or would that be too much weight on the front axle?
Weight in tires is un-sprung weight in direct contact with the ground and does not put weight on an axle. It is weight that has to be pulled up hills similar to pulling a trailer with the same amount of weight in the trailer.
As far as adding things, I would get it with cast wheel centers and a couple weight sets. That is about all I could think to add.
Wheel weights have a higher center of gravity than liquid ballast, but otherwise operates similar to liquid ballast.
Weight sets that mount on carriers are generally easy to remove, but do add weight to the axles. How much weight you add and under what conditions will determine how much the tractor life is shortened by as you would cause the tractor to work harder. If you need the weight to do a job safely you need the weight, that's just the way it goes.
I asked my dealer about a Torx Locker on the front axle. He was not sure how that might affect warranty if something went wrong.
On my Kubota tractor there is a foot leaver to lock the rear axle. Doing so adds strain to the tractor dependent mainly on if you're trying to turn or not, and how firm the ground is. If my BX
rear is locked while on a lawn the tractor wants to go straight and will rip up the grass while trying to turn, and the strain on the tractor is apparent, however it prevents sliding down wet hills and crashing into something, so I use it as experience has dictated the need.
Realize if a front locking differential was generally needed, it would be a factory option and the tractor would be designed to handle the related forces. From seeing all-around-lockers put on other vehicles I would guess doing this on a tractor would severely negatively affect reliability. If you think about how often off-road 4x4 vehicles with all-around-lockers break on the trails, even though those drivers have decades of vehicle experience, that likely foreshadows a similar outcome on a tractor.