I'm stuck in the middle ring on my road bike. When I try to shift up or down, the derailleur moves, but not far enough - the chain just rubs wickedly and doesn't actually shift. I noticed the problem afeter cleaning and relubing a couple of days ago, but it could have been that way a while as I've only been using the roadie for the commute to work recently and I barely ever change gear at all for that as it is a short, flat ride.

Any ideas?