TwistedPhil
+1y
With an on-top-of-the-axle setup, you can get away with a monoleaf, because the bag is balanced on top of the axle tube. With behind-the-axle brackets, the bag puts leverage on the back of the axle, which will make the axle twist when the bag lifts. The link setup will hold the axle solid to prevent this from happening, so you DEFINITELY want to run a link.
Of course, I'd highly recommend a link with either bracket setup, because it will ride better, feel more controlled, and generally make your life better!
-Phil at FBI