TT deceleration motor will do speed calibration before leaving the factory to ensure that the left and right differential speed of the two motors is within 3 revolutions. TT motor to maintain a long-distance linear movement, is the need to install more sophisticated, about the same weight! If there is a clear forward execution into a turn, it may be caused by the inversion of the motor wire. If the forward direction is inclined, it may be because the RJ25 wire or motor wire is pressed on the tire, resulting in increased friction and slower speed. I suggest you accept the wiring.