My rear wheel allignment is off a bit by the designated marks. I went to adjust (as per manual) and can't seem to find a tool that will fit the right rear axle nut. The left side (chain) axle nut takes an 8 perfectly (see pic) and the right won't take a 12 and the 11 wobbles around in it. Am I missing something here? Do I just loosen up the left side axle nut and adjust the right allignment after both clamp bolts are loosened? Do both retaining rings have to come off when making an adjustment on either side? When adjusting the chain slack the manual doesn't even mention loosening the axle nut or taking off the retaining ring? see pics