Tanks (vehicle)

• To improve traction and hence mobilty. Tracks also allow Tanks to cross gaps such as ditches.

• A tank weighs between 40 and 70 tons, depending on what model it is. If you built a tank with wheels, it would concentrate all that weight on a few small points, and the vehicle would sink into the ground. Tracks spread that weight out.

Following on from as said above, the key reasons why Military Tanks don't have wheels is because:

• Tracks on Tanks helps improve Traction and Mobility on all kinds of surface
• Reduce Chances of getting Stuck
• get rid of possibility of tyres can be blown (tyres can't be made bullet proof unless made of full bulletproof material.
• Tracks displace to weight of a tank on all parts of the track instead off on a single wheel.

The rule that "tanks have tracks, armored cars have wheels" is a very arbitrary one, and one which is increasingly wrong. In the current 4th generation of armored vehicles, the distinction between a "true" tank with tracks and an uprated wheeled fighting vehicle is very little, particularly in concept. In particular, current mobile armored warfare doctrine has three major roles for armored vehicles (not including things like artillery, vehicle recovery, etc.):

1. High mobility, Heavy Firepower vehicles able to quickly blast holes through enemy lines and then rush into the rear to wreck havoc with logistical and other support functions. Today, this is the task for the MBT (Main Battle Tank)
2. High mobility, Scouting and Screening vehicles are intended to search out the position of the enemy, and gather intelligence about strength, condition, and other tactical information. A wide variety of vehicles are used in this role by different armies.
3. Infantry Support vehicles are the infantry's best friend. Some of them are simply battle taxis, while others provide significant fire support and protection all on their own. APCs, IFVs, and a host of other vehicles now fill this role.

In the first category, mobility across a huge variety of terrain tends to be at a premium, as the ability to go anywhere quickly is key to mobile armored warfare. Tracks provide the best mobility across the widest terrain features of any vehicle propulsion system, due to both a huge traction advantage, and an extremely low ground pressure (a 70-ton Abrams M1A2 has less ground pressure per area than a soldier standing still). Thus, tracked vehicles are virtually the entire category.

In the scouting role, however, tracked vehicles are hardly the only option, and make up a slim majority of all such vehicles. The high mobility requirements are a large advantage over their wheeled counterpart, but there are significant disabilities that often result in wheeled tanks. Wheels are far faster over smooth, hard surfaces. They are also significantly quieter, and stealth is a major consideration for scouts. Additionally, wheeled vehicles have a higher reliability than tracked ones, and scouting missions often require long periods of time outside the logistical supply chain. Thus, this category is fairly evenly split between tracked and wheeled tanks, which otherwise have very similar characteristics. This is where you typically see something classified as a "light" tank. In fact, many armies have both a wheeled and tracked light tank available for use; they use the one most appropriate to the situation.

In the last category, most "tanks" actually carry infantry (though this is not exclusively true). The APC and IFV are the classic category vehicles, but newer ones such as the US's Armored Gun System also fit here. The prime design requirements for this category are moderate mobility (enough to keep up with the MBTs on many, but not all, terrain) and enough firepower to defeat common opponents of the infantry. Once again, wheeled and tracked vehicles are mixed here, and they are often use together.

Overall, tracks have the following advantages:

• Very low ground pressure, making movement over soft terrain easy. Ironically, modern tanks have so little ground pressure that they will not set off anti-tank mines.
• Extremely high traction, enabling them to climb very steep inclines and traverse extremely uneven terrain
• Long drive path, enabling the crossing of wide barriers and trenches.
• Relative immunity to small arms fire
• Very high maneuverability, able to turn in extremely tight spaces

They have the following disadvantages:

• High cost
• High complexity, and resulting higher maintenance (and lower reliability)
• Vulnerability to mid-range weaponry (autocannons and light AT rockets), which can quickly result in a "mobility kill"
• Loud sound signature
• High abuse of the surfaces they traverse, radically degrading it for further use.

Wheels on the other hand, have these advantages:

• Very high speed on hard surfaces, and correspondingly high fuel efficiency
• Relative simplicity of suspension, and relative ease of both maintenance and repair
• Multi-axle designs provide significant cross-country and extreme terrain performance, though not through very soft terrain.
• Advanced designs are mostly resistant to small arms fire, and, while easier to damage than tracks, are more able to operate when damaged.
• Significantly cheaper overall than tracked designs
• Quiet

Wheeled designs have these disadvantages:

• Poor performance over soft terrain
• High ground pressure, and vulnerable to mines
• Requires significant space for multi-axel designs
• Less maneuverable than tracks

Nowdays, tank designers take all of the above into consideration, and balance them again the design criteria to chose which to use. Thus, a "tank" (as defined as: "an armored vehicle armed with a large caliber main gun and significant armor protection") doesn't have to, and often doesn't, have tracks.

Naturally, it depends on what is mean by "types" of tanks.

If the question is referring to different models of tanks (similar to different models of cars, e.g. a Chevy Impala, Toyota Corolla, Toyota Camry, etc.), then, excluding specialty modifications (such as the amphibious modifications to certain M4 Shermans):

1. The British fielded about 24 different tank models, excluding those made by the USA. However, the vast bulk of the British tank force consisted of about 4 models.
2. The USA fielded about 7 different tank models, plus another 5 different tank destroyer models, which, from a design standpoint, should really be classified as tanks (unlike other countries' tank destroyers, which really were self-propelled artillery or assault guns). Once again, only about 4 models made up the bulk of production, with the M4 Sherman making up over 75% of all tanks produced.
3. The USSR fielded about 18 different tank models, with the T-34 making up the majority of their tank production.
4. The French had 10 different tank models, but saw virtually no action after the Fall of France in 1940.
5. The Italians fielded about 8 models, but none in large quantities.
6. The Japanese fielded about 15 tank models, plus another 4 different types of custom-design amphibious tanks. None were fielded in significant quantities.
7. Germany fielded 7 different models of tanks, plus over 20 models of tank destroyers, assault guns, and self-propelled artillery, though all of the latter lacked a turrent and should not really be classified as tanks in any way.

Most countries in WW2 began the war with a large variety of tank models designed in the 20s and 30s, virtually all of which were obsolete. In practically all cases, no more than 5 or 6 new models (from each country) were designed during the war, and the vast majority of tank production for the entire war centered around no more than 6 different models across all countries.

If the question is asking about the category of tank design (i.e. purpose/mission that the tank was designed to fulfill), then WW2 produced a myriad of different tank missions:

For the Allied powers, pre-war tank doctrine dictated three major categories of tanks:

1. Infantry-support: these were slower tanks, with heavy armor and powerful guns, intended to work in close-contact with infantry formations. In the British and French doctrine, these tanks (working in conjunction with special anti-armor artillery pieces) were intended to be the main anti-tank weapons. That is, enemy tanks were to be engaged by the Infantry-Support tank (as counterintuitive as that sounds)
2. "Cruiser" tanks, which included most Light and Medium tanks, where speed was th primary factor, with light armor and medium-caliber guns. These tanks were intended to be the "breakout" tanks, which would charge through openings that the infantry and infantry tanks would punch in enemy lines. As such, they were NOT primarily intended to be used against other tanks.
3. The tank destroyer, which was a particularly American ideology. These were medium tanks, build for very high speed and armed with a powerful gun, but with very little armor protection. Under American doctrine, the tank destroyer was the weapon to be used against enemy tanks, usually in a defensive roll.

In addition, the Allied forces produced a wide variety of add-ons and special mission conversions, numbering into the several dozen, including things such as amphibious kits, flamethrowers, mine-clearing, bridge-building, bulldozer, crane, and even rocket-launcher modifications.

As the war progressed, the Soviets were the first to discard this pre-war division, and focus on a more balanced design, combining mobility, good armor protection, and a powerful anti-tank gun. The outstanding medium T-34 and the solid heavy IS tanks were the result. The British eventually came around to this philosophy at the end of the war, producing the medium Cromwell and Comet which were good all-round designs. The Americans never did, however, instead pressing the M4 Sherman (a medium cruiser tank) into the utility roll, one which it was generally ill-suited for. Due to being knocked out early in the war, French tank designs never evolved.

German tank doctrine was different, generally delegating the infantry-support roll to the assault gun design, and assuming that tanks would be both mobile, and powerful enough to fight other tanks. While starting out with the generally weak Panzer I, II, and III models, the good Panzer IV was followed by the Tiger heavy tank, then the stellar Panther, followed by several increasingly ludicrous super-heavy designs (of which only the Tiger II saw any real action). Partially due to a change in war fortunes, German tank designs focused on producing increasingly powerful designs, intended to be able to beat any opponent in a 1-on-1 fight.

For both German and Allied designs, the light tank effectively disappeared after about 1942, as it was found extremely deficient in terms of protection (being vulnerable to even infantry-carried weapons) and not presenting enough firepower to be useful.

Frankly, neither the Italian nor Japanese tank forces developed effective tank doctrines, and neither really made much effort to develop new tank designs (or, for that matter, even manufacture many tanks).

The first German Panzer Tank was the Panzer I, various modes was made but most of them were produced by either the German:

• Henschel
• MAN SE
• Krupper
• Daimler-Benz

Reason for this was because the Panzer I was Hitlers first attempt to rebuilding the German Tanks since the war defeat of World War 1 and it took a while to build a model which was basic cost effective with maximum delivery.

It was only a Light Tank but it eventually opened a gate way of beautiful German Engineering of Tanks throughout the course of World War 2 such as the Panther, Tiger, King Tiger and would of been the Maus and E-100 and beyond.

Currently it is the (Chinese) Type 99KM, with a 155mm cannon. In the time of World War II, it was the Tiger Tank I, with an 88mm gun.

Two tanks attacked the Germans at Flers in the Battle of the Somme on 15 September 1916.

A total of 49 Tanks were allocated in this assault, of which 31 were mechanically fit to take part in the attack.

No, Russia did not have any tanks during the first world war, but like most countries, they were still in the making and would be released soon after.

Russia designed and experimented with some tanks before and at the beginning of the War, including the Mendeleev, the Lebedenko, and the Vezdekhod, but only two prototypes were made and none entered production. After the War some British and French tanks fell into Soviet hands, and the Soviet Union then began her own tank-building programme.