I have enough weight on my rear tires that tipping is not a concern. That being said looking at the physics of it weight in the rear tires does nothing to alleviate load on the front axle, and could even make it worse. A ballast box or heavy 3pt implement behind the tractor would however reduce the load on the front axle. Curious how big of a deal this is. Normally I have something on the back of the tractor but many times it is light enough that it probably isn't doing much.