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.
What causes whole body vibration. Vibration transmitted through the seat or feet (known as whole-body vibration or WBV) Drivers of some mobile machines, including certain tractors, fork lift trucks and quarrying or earth-moving machinery, may be exposed to WBV and shocks, which are associated with back pain.