Im currently creating models for a video game and came across a neat tutorial online for creating tank treads.  If you have not created them before, you'll be suprised how easy it is.  After you get through this tutorial you should be able to create treads for tanks or robots with no problem! Above is my result done in Autodesk Maya.

Tutorial Link: http://www-viz.tamu.edu/courses/tutorials/hunter/presentation1.htm