Each minute exterior detail on top-tier consumer performance cars like a McLaren 620R and professional race cars like an IndyCar or Formula 1 car is designed to make mechanical physics work to the driver’s advantage. Every millimeter of bodywork makes a difference in how the vehicle drives and performs, and the car’s relationship to the air it’s cutting through is paramount. A crucial part of this relationship is downforce, which can be harnessed and applied by aerodynamic parts throughout the car’s shape. The science of downforce can get fairly deep, but we’re here to give an overview of what it means and a breakdown of why it’s important to driving execution.
To define downforce with just a couple of words, it is vertical load created by a vehicle’s aerodynamic parts as it’s in motion. To boil it down even further, a car’s exterior components split, route, and direct airflow in a way that pushes the vehicle down and increases traction and stability. Front splitters, canards (also known as dive planes), rear spoilers, front spoilers, those massive adjustable air foils that Chaparral affixed to their badass Can Am race cars back in the day, and other aerodynamic bits all create downforce. Downforce keeps cars planted on the road at speed and ensures the tires are pressed firmly onto the road for maximum grip.
What’s cool about downforce is it can be used at both high and low speeds relative to the capabilities of the vehicle. Downforce is often associated with high-speed driving, especially cornering, such as an IndyCar that needs every teeny bit of grip it can muster as it courses through the Long Beach Grand Prix circuit. The Dallara-designed chassis is a prime example because of its heavy use of aerowork.
However, downforce plays into low-speed performance, too—this is why you’ll often see heavily modified autocross cars with massive wings. Despite autocross courses often featuring low-speed sections in their tight courses, cars with wings that have a lot of surface area can still use that air to help stay planted and shave thousandths of a second off of their run times.
Image: Peter Nelson
