SRAM Dual Drive 3X9 cable box installation and adjustment.
How do I install my SRAM Dual Drive 3X9 cable box?
The 3X9 hub is shifted by a thin rod that that is pulled by a cable operated lever inside a gray cable box. The shift rod screws into the right end of the hub axle. The cable box installs onto the end of the axle where the rod projects. The round black button on the top of the box must be pushed down flush with the top surface of the box before installing the box on the end of the axle and projecting shift rod. This is done when the hub’s shifter, and the lever it controls via the cable, is in the low gear setting. After the box is in position, the button is pushed up from the bottom side to lock the box in place. If the button is not already pushed down, the lever inside the box may need to be rotated slightly to align the bolt head on the lever, with the hole in the bottom of the box. This is the position where the button can be pushed down. The lever can be most easily seen when the black housing cover is snapped off of the end of the box. This cover is removable so the cable can be replaced if needed. Once the box is in position, the button is pushed up and the shifter should operate normally.
It is important to check the cable adjustment by shifting the hub to the direct drive second gear position. When in second gear the display window on the box should show two small yellow rectangles in alignment; one on the window, and one on the lever beneath the window. Use the black cable housing adjustment ferrule at the front of the box to align the yellow rectangles if needed. In low gear the cable is relaxed, in second gear the yellow rectangles align, in high gear the cable pulls the shift rod out fully and maintains a slight tension on the cable. When using a shifter that has fine shift trimming capabilities, it is important to learn the shifter indexing pattern that achieves the second gear alignment and still fully engages high gear with slight tension remaining on the cable. A periodic check of this cable adjustment should ensure reliable shifting.