[Alan Anderson]

Arcade drive uses the X and Y axis from one joystick. Tank drive uses the Y axes from two joysticks. You definitely need to have two different Joystick Get vi blocks, one for the reference to each joystick, and each followed by an unbundle by name to get the Y axis. The two values go to the inputs of the Tank Drive vi.

Don't use the stock Joystick Read vi to get your Y values. It only looks at one joystick. You can ignore it, or you can open it up and modify it to read your two joysticks.