Why do tractor tires sometimes fill with water?
It is not uncommon to see tractor tires filled with 75% water, beet juice or calcium chloride (not frozen). This is referred to as ballasting. These substances are added to increase the weight of the tires so that they do not slip. This increases the tractor's drawbar traction and saves fuel. Unlike adding metal weights to a tire, ballasting places additional weight at the lowest point of the tire.