I have seen every front wheel drive car I own have eventual vibration problems at the rear when tires get out of round. They will still have PLENTY of tread, just jack up the rear on one side and spin the tire, you'll see it, as much as 3/4" sometimes. Tire brand cheap/expensive will move that quality around, you'll lose MORE cash on the expensive tires because they have more rubber/tread than cheaper and thusly will get more out of round. Vibration will get bad enough that you will change the tires before they are nearly worn out. I think it's because there is no weight on rears anymore like when had full rearends back there. The assembly then is able to move up and down in harmonics while at speed where old time rear weight loaded tires/wheels enough to damp most of that out. As a result, I don't buy tires in 4s anymore, only in pairs. New ones go on front and fronts go on back. All the back wheels do anymore anyway is force the front of car to track straight. You need all the control on fronts now, and the fronts don't start that pattern mentioned above until they go on the back, because of engine/tranny weight. Since doing that, I am now able to wear out backs all the way to cord/steel if wanted, by then the vibration will have started but now the tire is worn out, change it. I buy tires more common now because only 2 but individually I get much more wear out of them. The tire bill gets spread out more too, easier to pay it.
