mattds

bump? does that vibration that i can actually feel point to tires or bearings or something else? maybe poorly balanced tires?

jcat_350

Sitting in the back puts strain on the rear suspension. As the suspension gets load put on it, the tires tend to camber a bit. If your rear wheel bearings are on the way out, this could result in a little extra lateral play causing a slight vibration.

Definitely follow oldgrump's recommendations in jacking the car up and looking for play in the hub. Do so with one hand at 9 o clock, one hand at 3 o clock and alternate to check for horizontal play, then do the same at 12 and 6 to check for vertical play. It's a good time to check out suspension bits while the car is up in the air. Unless you see an obvious flaw (bubble etc.) in the tires, I'm inclined to think it's likely the rear wheel bearings.