Sorry I forgot to mention that I once owned a static bubble balancer.AfterI would level it up and center the bubble,arrange the weights after placing the wheel on the centering cone until the bubble was again centered,and hammering the weights on, that if I simply moved the tire onto a different position the bubble would then show an imbalance.We could speculate on possible reasons for this-but the bottom line is I quit balancing wheels,and have never looked back.