If I grab the outer edges of the large cassette, I get a little side to side wiggle with my rear hub. The cassette itself is not loose and is tight on the hub so I'm guessing the bearings need to be repacked and/or replaced. Is it possible to have this thing serviced or is it a sealed system? I've never broken down a hub before so I'm very cautious about tearing it apart. If it can be done, I'll likely take it to my LBS.