Answer. First, rear driven cross trainers have the flywheel in the back. As a result, your feet move in an elliptical manner mimicking natural running or walking. Also, rear driven cross trainers generate smoother motion.   On the other hand, front driven cross trainers have the flywheel in the front. As a result, your feet move in a circular motion. Also, the stride feels like you are climbing steps. Furthermore, these cross trainers often take up less space than rear driven cross trainers.