Aerodynamics And You: Coast Down Testing

For the last two weeks we have been keeping you informed of the most popular methods of aerodynamic testing. Keep in mind that at high speeds, aerodynamic drag is to blame for approximately 25% of your truck’s fuel losses! Coast Down testing is another aerodynamic testing method used to measure aerodynamic drag. Read below to learn more!

Coast down testing is used to calculate the resistance caused by drag that a vehicle in motion encounters. Drag pushes the vehicle in the opposite direction of its motion, thus creating resistance. In order to combat such resistance, the vehicle’s engine must work harder. So, by reducing drag, a truck’s engine requires less power to push forward, which in turn requires less fuel. The test is conducted on a flat stretch of road while the vehicle is decelerating. Many factors must be taken into account before starting a coast down test. These include the mileage of the vehicle, ambient temperatures, wind, barometric pressure, and much more. Once the vehicle reaches a speed of almost 75mph, it is put to neutral and is allowed to coast until it stops.