[Kit Gerhart]

The difference in no-load rpm of the drill motors has been pretty well covered here, but it should be also be noted that there is also a significant difference in the horsepower the drill motors put out in the two directions. I roughly measured it with a dyno built by one of my team mates few years ago, and there was at least a 10% difference in power between forward and backward. Since we tend to drive our robots in both directions, it may not be worth chosing a motor direction for forward and backward on the robot, but as anyone will know who has driven a robot powered by drill motors only in a "symmetrical-looking" drive train, it IS worth the effort of trying to have both motors turn in the same direction for a given direction of robot travel. The non-symmetry of the Chias is much smaller than that of the drills, though.