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.
1 If a tire is damaged, deflate it and replace it with your spare. If you do not see any tire damage and cannot identify the source of the vibration, take the vehicle to a tire dealer for a thorough inspection.  If you see something youâre not sure about during your inspection, have it examined by your tire dealer.