My rear wheel is making a rubbing/whirling noise at some point of its rotation. The strange thing is it does not always happen as I ride. I put the bike on its side and gave the wheel a wiggle to see if perhaps the wheel was loose on the hub. It does wiggle a tiny bit, is this normal? When I rotate by hand I can stop the noise if I pull the wheel up slightly as I rotate. Any ideas what to look for?
Cheers.