Great link. Very interesting. It looks like it is more applicable to large tractors that do a lot of one type of activity. Those of us with compact/utitlity tractors do so many different activities that it would be quite hard to ballast and inflate to maximize traction and minimize compaction in all of those circumstances. The use of a FEL requires so much ballast on the rear of the tractor, probably more than is necessary than for pulling a disk or plow. But, there are certainly lessons to be learned there. Thanks for the link.