Smooth, uninterrupted airflow is what you're looking for in vehicle aerodynamics. By deflecting air that either, spills into the trailer gap, or that bypassed the tractor and approached the trailer from an angle, the Nose Cone can add 1/2 to 1 mile per gallon to your mileage.

Nose Cone treated trailers allow variances in tractor-trailer height and distance between the tractor and trailer with no consequence to fuel economy. Crosswinds (winds approaching the vehicle from an angle) increase drag from 20 to 100% depending on the degree and speed. Nose Cone alleviates these costly, yet common occurrences of windy weather and also improves trailer stability.

Side-Burns work much the same way as cab-extenders do, deflecting wind along the trailer sides. The advantages of Side-Burns are that they are applicable at any tractor-trailer spacing, and will never interfere with turning radius. In addition, even with today's tractors, trailers are often wider than the tractor; this added width side to side causes an interruption in airflow that is diverted with Side-Burns.