Fan Info - INDYCAR 101 - Glossary

Glossary Of Racing Terms


Accelerometer: Device in a driver’s earpiece that measures the forces a driver’s head experiences in an impact.

Adhesion: The maintenance of contact between two touching objects. Adhesion refers to a static condition, whereas traction (also known as “grip”) refers to a moving condition.

Aerodynamics: As applied to racing, the study of the interaction between air and the resistance and pressures created by the passage of a moving car through the air.

Apex: The area of a turn near its center.

Apron: The paved (and usually flat) portion of a racetrack that separates the racing surface from the infield. Generally, a concrete wall or steel guardrail separates the apron from the infield.

Blister: Bubbles on the surface of a tire created by overheating of the tread compound.

Boost: Manifold intake pressure above ambient atmospheric pressure.

Buckeye: External opening to fuel cell. Fuel hose connects securely to buckeye during refueling.

Camber: Degree to which right-side tires lean in toward the car (from the top of the tire) and the left-side tires lean out. A useful tool to gain grip in corners by maximizing the amount of tire-to-track contact.

Camshaft: A rotating shaft in the engine that opens and closes the engine’s intake and exhaust valves. 

Chassis: The central body of the car, including the driver’s compartment. Also referred to as the “tub.”

Contact patch: The portion of the tire that makes contact with the racing surface. Various chassis and tire adjustments can be made to maximize the contact patch.

Crankshaft: The rotating shaft within the engine that is turned by the up-and-down motion of the pistons. The crankshaft transfers power to the flywheel, and in turn to the transmission. The crankshaft is housed within the crankcase, which is part of the engine block.

Diaper: A blanket made from ballistic and absorbent material that surrounds part of the engine and serves as a containment device during accidents and engine malfunctions.

Disc: In brakes, the rotor, the part which revolves and against which brake linings are pressed during braking.

Displacement: In an engine, the total volume of air-fuel mixture an engine theoretically is capable of drawing into all cylinders during one operating cycle.

Downforce: Creation of force through aerodynamics, which keeps the car stuck to the track. High-speed movement of air underneath the car creates a vacuum, while the wings on the car force it to stay on the ground, acting in a manner opposite to the wings on a jet airplane.

Drafting: See “Tow.”

Dyno: Short for “dynamometer,” a static machine used to measure an engine’s horsepower output.

Engine block: An aluminum casting from the manufacturer that contains the crankshaft, connecting rods and pistons.

Ethanol: Alcohol derived primarily from grain. As a clean burning and renewable fuel that is non-toxic and 100 percent biodegradable, it reduces harmful air pollution and improves racing’s environmental footprint. Its high octane rating delivers strong engine performance by helping engines resist detonation so they can run higher compression ratios. IndyCar Series cars use a blend of 85 percent ethanol and 15 percent gasoline (E85).

“European-style” qualifying: Timed session in which all cars run on the track simultaneously to post the fastest lap. Typically used in road/street racing events.

Fuel injection: A system replacing conventional carburetion that delivers fuel under pressure into the combustion chamber of the engine (direct injection) or air flow before entering the chamber (multi-point fuel injection).

Grip: How well the tires maintain traction through contact with the racing surface.

Groove/line: Term for the fastest or most efficient way around the racetrack. Often most drivers will use the same groove around the racetrack, and that portion of the track will consequently appear darker in color than the rest of the track due to the buildup of tire rubber.

Handling: A race car’s on-track performance, determined by factors such as tire and suspension setup, and other aerodynamic issues.

Frontal head restraint: A yoke-collar safety device designed to reduce extreme head motions and neck loads during high-speed impacts.

Loose: The rear of the car is unstable due to a lack of rear-tire grip caused by too much front downforce or not enough rear downforce. Also known as “oversteer.”

Marbles: Excess rubber build-up above the groove on the track, the result of normal tire wear throughout the race.

Neutral: Term used to describe the handling of the car when it is neither loose nor pushing (tight).

Nomex: Trade name of DuPont, a fire-resistant fabric used in the manufacturing of protective clothing.

Paddle Shift System: A pneumatic gearshift system that allows the driver to keep both hands on the steering wheel during shifting by using paddles located on the back of the steering wheel to shift up and down. The paddle shift system has its own control unit that is in sync with the engine, so it knows what gear the driver is in, engine RPMs and the speed of the car.

Podium: The top-three finished in an event stand on a podium (or stage) to be recognized after the race. The winner is usually in the middle on a higher pedestal, flanked by the second and third place finishers.

Probe: Nozzle which is attached to fuel hose and connects securely to buckeye during refueling.

Pushing: The car does not want to turn in the corners due to a lack of tire grip. This can be caused by a lack of downforce on the front of the car or too much downforce on the rear of the car. Also known as “understeer” and “tight.”

Rev limiter: Electronic/computer device in the engine controls which causes a controlled engine misfire if engine revolutions per minute (rpm) exceed the limit set by INDYCAR rules. The legal rpm (or “rev”) limit is 12,000 rpm. The rev limiter is used primarily to control speeds, thereby increasing safety and controlling costs.

Ride height: The distance from the bottom of the chassis to the ground when a car is at speed. INDYCAR rules stipulate that the ride height of the sides of a car should be 2 inches off the ground for all tracks.

Short track: Racetracks that are 1 mile or less in length.

Side-pod: Bodywork on the side of the car covering the radiators and engine exhaust. Aids in engine cooling, car aerodynamics and driver protection in the event of a side impact.

Single-point fueling: Refueling system which utilizes one hose for fuel distribution and venting.

Slicks: A treadless tire, used only on dry surfaces. Slicks provide maximum contact with the track surface, thereby enhancing grip. In wet conditions, treaded tires are used to dissipate the water build-up between the track and the tire surfaces in order to increase grip.

Stagger: Right-front and/or right-rear tire is larger in diameter than left-side tires in order to improve turning ability on ovals.

Sticker tires: Slang term for new tires, derived from the manufacturer stickers placed on each brand-new tire.

Superspeedway: A racetrack of more than 2 miles in length.

Suspension & Wheel Energy Management System (SWEMS): Wheel-restraint system using multiple restraints attached at multiple points to a car’s chassis and suspension designed to minimize the possibilities of wheel assemblies becoming detached during high-speed accidents. The restraints are made of FIA-approved Zylon. This material, with its high-tensile properties and its wound construction (opposed to woven), has a breaking strength of 5 tons. INDYCAR introduced SWEMS in May 1999.

Telemetry: A radio device that relays information such as engine, tire, steering and throttle performance to team engineers in the pits. The team can monitor both car and driver activity to ensure the car is performing properly. Also enhances driver safety by allowing the team to notice any developing mechanical problem the driver cannot foresee.

Tight: Also known as “understeer.” A handling condition characterized by a lack of grip in the front tires. As the driver steers through a turn, the front wheels want to continue straight ahead.

Tire compound: A formula based on rubber polymers, oils, carbon blacks and curatives used to create a tire. The varying lengths and banking of Indy car tracks require different compounds.

Toe: Refers to the alignment of the front and rear tires. If tires point inward, the condition is called “toe-in.” If tires point outward, the condition is called “toe-out.” Correct toe settings are essential in order to maximize grip.

Tow/drafting: As a car moves around the track at 220 mph, it literally splits the air, some of which goes over the car, and some of which goes beneath. This lack of air behind the car creates a vacuum, which a trailing car may use to be pulled, or “towed,” by the lead car.

Turbocharger: A turbocharger routes engine exhaust gases to turn a turbine at speeds approaching 100,000 rpm. The turbine powers a compressor that forces a greater volume of air into the engine's intake system, thus increasing horsepower and fuel efficiency. All IndyCar Series cars utilize a twin-turbocharged engine.

Variable Ratio Steering Rack: The primary steering mechanism of a car, the steering rack consists of a metal bar with a series of evenly spaced teeth that links to the front wheels of the car. A pinion controlled by the driver turning the steering wheel catches on the teeth of the steering rack, causing the wheels to turn. On a variable ratio steering rack, the teeth on the steering rack are pitched and spaced closer together at each end of the rack. A different shaped pinion is also used. Together, these changes diminish the effort required by the driver to turn the car.

Weight jacker: A hydraulic cylinder the driver controls to adjust car handling. The cylinder is mounted on top of a rear shock spring and compresses or extends, which transfers the car’s weight distribution from one side of the car to the other, thereby adjusting the car’s handling to the driver’s liking.

Wicker bill: A long, narrow, removable spoiler made of steel, aluminum or carbon fiber on the trailing edge of the front and rear wings which varies in height, creating downforce. Teams will use different sized wicker bills to create more or less downforce. The larger (higher) the wicker bill, the greater the downforce, and vice versa for smaller wicker bills.