New Army studies indicate that wheeled vehicles may not be significantly cheaper to operate than tracked vehicles, depending primarily on the terrain over which the vehicles will operate. This contradicts moves by General Shinseki to switch from tracked to wheeled vehicles, a move partly inspired by the well-known savings to be found in wheeled vehicles. Wheeled vehicles are "known" to be more reliable, to be more easily repaired, and to use less fuel. The Army study could not find these savings, and analysts are pouring over the details trying to better understand the cost figures. Supporters of the "medium" Army insist that the study is rigged to favor tracks by overweighing the need for cross-country combat performance, as opposed to the more common peacekeeping and stability missions. Medium advocates also insist that weight (as in how much one had to carry halfway around the world) was the reason for wheeled vehicles, not cost, therefore even if there were no savings the wheeled alternative should still be pursued. Even so, the new studies have shown that wheeled vehicles put to hard use in difficult terrain cost as much to maintain as tracked vehicles. Tracked vehicles, on a per-ton basis, generally have more internal volume because more of their suspension and drive systems are "outside" of the armored envelope. Analysts noted that the Army wants a vehicle that will have to weigh about 25 tons to do all of the jobs assigned and provide adequate volume and protection. Once wheeled vehicles get over 20 tons in weight, their cost and mobility advantages start to disappear quite rapidly. In that Army's preferred weight zone, tracked and wheeled vehicles are about equal in most regards. --Stephen V Cole