For me it's a non issue. I tried it both ways. My box blade weighs almost 1000lbs. That is not huge, but is considerably more then both tires (R4's) ballasted when you consider the moment increase you get with a box hanging 4 or 5 feet off the back. Frankly, I noticed no stability increase when the tires were loaded when using it on my hills other then it did want to slide down easier on the wetter grass with loaded tires. I surely noted the extra effort required by my engine when going uphill when mowing using loaded tires. My loader, a LA 723 cannot lift the rear end off the ground even with the toothbar on and the additional heaping it allows when loading the bucket using my box scraper as ballast. This is true even on a downhill slope although I am sure things are getting light back there. Bob's right though, I drove my neighbors (identical to my tractor except R1's on his) several days ago as a favor to unload 2500' of pipe fencing off a semi trailer. Even though his R1's are loaded, the loader easily tipped the rear wheels. He has no box scraper so I had to put one on in order to continue unloading the truck. The problem was he has forks over the bucket and the load was out to the end of the forks. Even though the bundles were only about 700lbs, the loader and the tractors size could just barely do it. The problem was two fold. Not enough ballast and defintely a setup with the forks that it was not designed for. I would advocate quick attach forks instead of the over the bucket anytime unless your dealing with very light loads. You will need ballast of some sort with all but the lightest of loader work. If you have a nice heavy box, I would opt not to load, otherwise I would load. It works well for me and my combination of mowing, loader/boxscraper and powered landscape rake uses.
