Configurations are provided for vehicular robots or other vehicles to provide shifting of their centers of gravity for enhanced obstacle navigation. A robot chassis with pivotable driven flippers has a pivotable neck and sensor head mounted toward the front of the chassis. The neck is pivoted forward to shift the vehicle combined center of gravity (combined CG) forward for various climbing and navigation tasks. The flippers may also be selectively moved to reposition the center of gravity. Various weight distributions allow different CG shifting capabilities.