From what I kinow German sprockets were in the front as it gives a tank a greater climbing factor for two reasons
easier to pull something especially when it is the loosest portion of the track. Sprockets at the back not only strain the track pulling all that weight but it stretches the track while the weight is on it, in effect doubling the strain on links.
Having the extra weight at the front for the gearing also helps the tank climb over obstacles.
like I said from what I know which sometimes fits in a teaspoon.