[Al Skierkiewicz]

R,
Be sure that your speed controllers are calibrated as well. This method causes the controllers to interpret the joystick for full throttle forward and reverse. A good indication that you need this is that the motors creep when the robot is lifted off the floor. Another quick check while you have the robot up is to command it to full throttle forward and check the indicators on your speed controllers. They should all reach full and all at approximately the same joystick position. Repeat for full throttle reverse.