Car spoilers: truths and myths

Spoilers are a popular accessory for many car enthusiasts. On top of being stylish, many people believe they can improve a car’s speed and aerodynamics. Here’s what the science says.

How spoilers work
The spoiler’s effect comes from the same physical laws that drive aviation, but it works in the opposite direction. While an airplane wing lifts the aircraft as it accelerates, the spoiler on a car exerts a downward force, pressing the vehicle downward and improving traction. It also decreases the drag arising from air turbulence at the vehicle’s rear.

Spoiler effects
The spoiler’s aerodynamic effect is indisputable. But its effectiveness is proportional to speed. For example, a Formula 1 racing car benefits most from a spoiler because it’s lightweight and frequently exceeds 185 miles per hour.

Cars intended for consumer use are much heavier and subject to legal speed limits. For these types of vehicles, the downward thrust effect of a spoiler is negligible. However, spoilers reduce drag, which helps reduce fuel consumption. This effect is especially true if the manufacturer installed the spoiler and tested it in a wind tunnel, which is often the case for high-end cars.