Centra Balance work on the basic principles of physics. Vibrational Resonance is the up and down vibration pattern created by a rotating tire and wheel that is out of balance, forcing the liquid weight fluid which is free-moving within the ring to positions along the ring, which exactly offset any light and heavy spots, thereby eliminating the vibration and creating equilibrium within the rotating mass. Once properly positioned, Centrifugal Force holds the mercury fluid in that position unless a different vibrational resonance pattern develops from tire wear or from stones, mud or ice sticking to the tire or wheel, which instantly forces the fluid to its new equilibrium positions.