Yes, I just took my chain off and tested it, it spins very smoothly. However, I noticed that there was way too much play, as if the floating cup wasn't screwed in far enough. So I screwed it in farther, screwed the lock ring on, reattached the crank arm, and gave it a test ride. The grinding/rumbling problem seemed to have become less noticeable, however, after about 15 minutes of riding, there was way too much play again, and I had to screw the floating cup in farther. This also isn't the first time this has happened, I've had to do this every time I've gone out on a ride. The floating cup seems to somehow loosen itself, even though the lock ring is on TIGHT.