I also have ran M/T tires for a very long time (around 1988 to present). Used to mount tires w/tubes and no balancing was needed. The last 8 or so years, I've had to balance every one of them, with some needing a lot of weight. Also sent one pair back to the dealer because in addition to needing a lot of weight to balance it, it hopped like a bunny rabbit just driving it in the pits. Car is a lot smoother on track and in the burn out after the tires are balanced.

Brian