I don't think you can feel or hear a tire that is out of balance at speeds below 25-30.... What you are more likely to feel or hear is a slightly bent wheel or a tire that is out of round, either of which will also cause it to be out of balance... Your tires can be perfectly round, and wheels perfectly straight, but still out of balance and you won't hear or feel anything until you are up to about 40-45... Out of balance is happens with inertia, and there isn't much inertia until you are moving faster than 25... I have one slightly bent wheel, and I can hear it in my new tires while going at any speed,,,, but with proper balancing, I can't feel it at all... It did take a couple of tries to get the balance to compensate correctly, but it did work.... So again, I can hear mine sound out of balance even at 10-15,,, but I don't feel them at any speed.... If you can hear or feel what seems like an out of balance tire at speeds below 30, then I would bet you have a slightly bent wheel,, which is actually very common.... I can't remember the last time I had any of my vehicles in the tire shop and they didn't find a slight bend in one of the wheels.
