Yet they were cheap enough to be built in large numbers. Typical Main Battle Tanks were as well armed as any other vehicle on the battlefield, highly mobile, and well armored. The Main Battle Tank thus took on the role the British had once called the 'Universal tank', filling almost all battlefield roles. Even reconnaissance vehicles had shown a trend towards heavier weight and greater firepower during World War II speed was not a substitute for armor and firepower. Likewise, World War II had shown that lightly-armed, lightly-armored tanks were of little value in most roles. The World War II concept of heavy tanks, armed with the most powerful guns and heaviest armor, became obsolete since they were just as vulnerable as other vehicles to the new medium tanks. This transition happened gradually in the 1950s, as it was realized that medium tanks could carry guns (such as the US 90 mm, Soviet 100 mm, and especially the British L7 105 mm) that could penetrate any practical level of armor at long range. Just don't call it a light tank.Medium tanks gradually evolved into the new concept of the MBT. The 'light tank' of the future could be dropped out of airplanes, ringed with radars and other sensors, run on six or more wheels, and hurl tank-shattering missiles up to five miles away. The common conception of a light tank is a small, pudgy vehicle with a pipsqueak of a gun and a cramped, miserable with a short battlefield lifespan. Wheeled armored vehicles are better at navigating bad terrain than ever, with the added advantage of creating a lighter vehicle with better mobility on roads. Now that the Army has purchased the Stryker interim armored vehicle in large numbers, it's much less resistant to wheeled designs than it has been in the past. Tracks are better able to shrug off battlefield damage than wheels, and they are better in some types of ground-particularly crossing ditches or muddy, rough terrain.

Army resisted wheeled armored vehicles, preferring tracks over wheels. For larger projectiles, an active protection system would keep the tank crew safe.

light tank could dispense with much of its armor-perhaps keeping just enough to stop 12.7-millimeter heavy machine gun bullets. Active protection systems such as the Israeli Trophy and Russian Arena, which use radar antennas to track enemy rockets and missiles and shoot them down with shotgun-like blasts, can protect a small tank just as well as a large one. Protection: Here's where the light tank will benefit the most from technological innovation.

Medium modern tank