TAKE THE THUNDER OUT OF THE BIG RIGS.

Noise from an exhaust system is composed primarily of three sources: out-the-stack emissions, radiated noise from the muffler surfaces, and unshielded pipe noise. Fans and radiators run a close second to exhaust systems as the chief noise source on trucks. Engine noise sources are considered to fall into those that can be treated by modifying diesel engine combustion characteristics and those that can be enclosed or shielded. Perhaps the least treatable noise source on heavy trucks is the tires. A radial tire with the same tread pattern as a bias ply tire produces the same amount of noise, but radials can use a relatively quiet tread design and still provide adequate service life.