[Joey Milia]

Your placement of the chain sprockets on the outside of the frame should allow you to simplify your axle set up in ways that most WCDs can't do. By bolting the sprocket directly to the wheel there is no longer any need for the axle to be live. This means that you can have the bearings only in the wheels and eliminate the bearings in the frame. It also means that you can replace the hex shaft with a round shaft possibly simplifying machining and allowing you to use cheaper bearings. You should still have the blocks to move the axles, allowing the chain to be tensioned.

These simplifications would only apply to the outside wheels, the center wheels should still be driven by the hex shaft from the gearbox.