Rolling the bike in to the garage after a 150 mile ride yesterday I heard a creak from the rear wheel. On the rear stand, the sound occurs at a single spot, I'd say across about 30 degrees of rotation. Not the chain, not the disc, sounds like it's inside the rear wheel. Could a bad wheel bearing do this? I suppose I'll pull the wheel and regrease the axle and spacers today but it's something I've never heard.