This isn't a serious problem, but I've noticed a "rubbing" sound coming from my front wheel. It's only hear it when I'm standing on my pedals leaning towards the front of the bike. At first I thought it was always there and I could only hear it when I'm standing, but now I'm convinced it only happens when I've got my weight leaning forward.
The brakes are not rubbing at all and I can't find anything else getting in the way. It sounds exactly like a rubbing brake pad though.
Is there anything I should be looking for?