A tank that can't traverse broken or muddy terrain isn't going to be much use to anyone, and thus significant thought was given to the makeup of the suspension of German and Soviet tanks. While the Germans pursued ever more complex and versatile suspension, the Soviet engineers became famous for incorporating ruggedness and mechanical reliability into their more simple suspension systems.

The basic elements of a tank's suspension are its drive wheels, its roadwheels, its idler wheels, and its return rollers . The configuration of the roadwheels could produce a variety of different suspension systems, while the position of the drive wheels/idler wheels would produce different degrees of torque (how much engine horsepower would be converted into actual movement).

The most basic idea of a tank's drive system and suspension is as follows. The various wheels of a tank's suspension form a "frame" around which the tank's treads are laid. As the drive wheel turns, its gear teeth grip the treads and make them run around the other wheels in the tank's suspension much the same way a conveyor belt's belt moves over the rollers. The tread has a much greater grip on the ground than normal wheels would, and thus the tank can traverse a much greater variety of terrain than a normal wheeled vehicle.

The roadwheels are the core of a tank's suspension system. Just as the suspension in one's car ensures a more or less smooth ride on bumpy roads, a tank's suspensioin system ensures that the tank remains stable as it traverses the obstacles that more often than not litter the battlefield.

As a tank moves over a tree trunk, for example, one would expect the whole tank to have to mount the height of the log. Instead, it is the roadwheels, on their independent springs, that are forced up by the obstacle - even as the tank remains stable.

Germany and the Soviet Union had different standard qualities that were built into their tanks, and this is reflected in some of their roadwheel designs. The Soviet tanks incorporated the most basic of roadwheel designs, offering good overall cross country performance in exchange for mechanical robustness and ease of maintenance. The German attachment to more complex and finely engineered tank innovations led to a remarkable array of new designs for tank suspension. The most successful was the idea of interleaving the roadwheels (see bottom right) as opposed to the standard form of suspension (see top right). Interleaved roadwheels gave incredible cross country performance; at the cost of mechanical complexity and fragility.

HOW TO LOCATE A TANK'S ROADWHEELS

A tank's roadwheels are the row of wheels that border the bottom edge of the tanks treads. For examples of interleaved and independently sprung roadwheels, see the pictures to the bottom right and top right respectively.