Lift amount does NOT equal spacer thickness owing to the suspension geometry. Lift spacer is not equal to the actual spacer thickness. The lift amount and the spacer thickness will NOT be the same, in order to lift your vehicle the advertised height, it is necessary that the spacer is less than the lift amount. The suspension (lower control arm) compounds the amount of lift due to both its length and angle and that is the reason why the spacer needs to smaller than the lift amount. What is a leveling kit? .