[wt200999]

You have a couple ways on implementing it. I wouldn't suggest editing the WPILib, at least not yet as there will still be patches that may overwrite what you do. You could create your own class and inherit that. Or you could create your own Joystick class instead, inheriting the Joystick and adding the scaling to the GeyY() function (or if you assign a different axis for drive). There is also RobotDrive::TankDrive(float leftDrive, float rightDrive) that you could use when the trigger is pressed. The function is defined in RobotDrive.h