Air Pressure

Air pressure in motorsport refers to the amount of compressed air inside a race car's tires, measured in pounds per square inch (PSI) or bar, which directly affects how the car handles, grips the track, and performs during a race.

Think of a tire as a balloon filled with air. The amount of air you put inside determines how firm or soft it feels. In racing, this firmness is critical because it changes how the tire makes contact with the track surface. Too much air pressure makes the tire hard and bouncy, while too little makes it soft and floppy. Race teams spend considerable time finding the perfect air pressure for their specific conditions.

Tire pressure affects almost everything about how a race car drives. When a tire has the right air pressure, it provides maximum grip for accelerating out of corners, braking hard before turns, and maintaining speed through curves. The contact patch—the small area where the tire actually touches the road—changes size and shape based on air pressure. Getting this right means the difference between winning and losing.

Race engineers typically adjust tire pressures in very small increments. A change as tiny as 1.5 PSI can noticeably alter how the car feels to the driver. For example, GT3 race cars usually run tire pressures between 25 and 29 PSI, which is actually higher than what you'd use in a regular street car. These precise settings help the team balance the car's handling between the front and rear axles.

Temperature plays a huge role in tire air pressure. As tires heat up during racing—from friction with the track and flexing at high speeds—the air inside expands and the pressure increases. Teams must calculate "cold pressures" before the race, knowing they'll rise to a target "hot pressure" once the car is running at full speed. This relationship between temperature and pressure is something engineers carefully monitor throughout a race weekend.

Weather conditions also dictate air pressure choices. In wet conditions, teams often increase tire pressures slightly to help prevent aquaplaning, where the tire rides on top of water instead of cutting through it to reach the track surface. In extremely hot weather, teams might start with lower cold pressures, anticipating greater expansion as the tires heat up.

Safety is another critical reason why air pressure matters. Under-inflated tires generate excessive heat from flexing too much, which can lead to dangerous blowouts at high speeds. Over-inflated tires reduce the contact patch so much that the car loses stability and becomes unpredictable to drive. Both scenarios can cause accidents, making proper tire pressure essential for driver safety.

Beyond tires, air pressure also refers to aerodynamic forces in racing. The air flowing over, under, and around a race car creates areas of high and low pressure that generate downforce—the invisible force pushing the car onto the track for better grip. However, when most racing professionals talk about air pressure, they're almost always referring to what's inside the tires, as this is something teams adjust constantly throughout a race weekend to optimize performance.