1. (Units) a unit of heat in the fps system equal to the quantity of heat required to raise the temperature of 1 pound of water by 1Â°F. 1 British thermal unit is equivalent to 1055.06 joules or 251.997 calories.
Quick Answer. A major factor that usually causes tire noise is the air chamber inside the tire. The large void that is filled with air acts as a giant resonance chamber. Thus, the tires are something like donut-shaped drums that generate a low-frequency hum when tires are rolling.
A. This will be tough to diagnose without driving the car, but your accurate description of the symptoms provides a great start. My hunch is this is tire or wheel bearing noise. Let's start with a look at your tires. Under-inflated tires can make unusual noises, as can tires with cupped or irregular tread. Unusual tread wear can be caused by incorrect inflation, incorrect wheel alignment, unusual driving habits, or lack of routine tire rotation.