Over the life of a tire, the tread wears, resulting in a surface that is heavier in some areas and lighter in others. Equal FLEXX shifts to the lighter tread areas to compensate for the uneven weight as the tire spins. Unlike wheel weights, FLEXX perpetually adapts to balance a wheel assembly and tire. Trucks are more fuel efficient this way since tires stay on the road longer, which saves the end user money. Tires are at their peak fuel efficiency in the last 20% of wear, so longer wear helps your fleet take advantage of these savings.