A British thermal unit (Btu) is a standard unit of energy that is used in the United States and sometimes in the U.K.
There is another defect in tires that can cause a vibration called loaded road force variance. The tires and pass a visual inspection, a radial and lateral runout test, be perfectly balanced, but still cause a vibration. This is due to the internal defects in the tire.
This type of vibration is mainly caused by the tires which are out of round, out of balance and have bulges or flat spots. In addition, the car can also vibrate at certain speed because of the damaged brakes or bent wheel. It can also be caused by the damaged drivetrain components or the suspension or steering parts.