I've felt a "lug"/"drag" feeling while riding my X. It's during the rotation of the rear wheel, somewhere. I thought it might have been rear wheel bearings. I have two rear rims, so I swapped out the rear wheel and I thought It was good until I started to cinch tight the adjusters & axle nut. With the chain off the wheel spins easily. When I have the chain on it has a drag, during the rotation. It does not stop in the same spot. If you pull the front wheel down, (when it's in the air) it spins freely. The rear wheel will spin and then noticeably "cease". I took the chain off, put a socket&ratchet on the counter shaft gear bolt (front gear) and turned the transmission gearing over (neutral) and the "lug/drag" feeling wasn't there. I put the chain back on, adjusted the chain and fasteners to spec., turned the rear wheel by hand and it gets that drag back. The chain-sprocket alignment doesn't appear out of line. The second rim that I installed does not have the rear brake disk on, so I can eliminate that. Any ideas?