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, steel guardrail or SAFER Barrier 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 leftside 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 that 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 of an 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 nontoxic and 100 percent biodegradable, it reduces 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. NTT IndyCar Series cars use a blend of 85 percent ethanol and 15 percent gasoline (Speedway E85).

"European-style" qualifying: Timed session in which all cars run on the track simultaneously to post the quickest lap. Used in NTT IndyCar Series road/street qualifications.

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

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. 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 because of the build-up of tire rubber.

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

Loose: Terms used to describe that rear of the car is unstable because of 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 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 car is in, engine RPMs and the speed of the car.

Podium: The top three finishers 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 that is attached to fuel hose and connects securely to buckeye during refueling.

Pushing: Term used to describe that car does not want to turn in the corners because of 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.”

Rev limiter: Electronic/computer device in the engine control unit that causes a controlled engine misfire if RPM exceed the limit set by INDYCAR rules. The limit is 12,000 RPM. The rev limiter is used primarily to control speeds upon entry to pit lane.

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.

Sidepod: 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 that utilizes one hose for fuel distribution and venting.

Slicks: A treadless tire, used 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 buildup between the track and the tire surfaces in order to increase grip.

Stagger: Right rear tire is larger in diameter than left rear tire, causing the race car to naturally want to turn left, to improve turning ability on ovals.

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

Superspeedway: An oval racetrack of 1.5 miles or more 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 possibility of wheel assemblies or wings becoming detached during high-speed accidents. The restraints are made of FIA-approved Zylon.

Telemetry: A radio device that relays information such as engine, tire, steering and throttle performance from the car on track to engineers on pit lane. 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.

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.

Tire compound: A formula based on rubber polymers, oils, carbon blacks and curatives used to create a tire. The varying lengths and banking of racetracks 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 the race car moves around the track, it splits the air, some going over the car and some beneath. This lack of air behind the car creates a vacuum, which a trailing car may use to be pulled or “towed.”

Turbocharger:Routes engine exhaust gases to turn a turbine, which powers a compressor that forces a greater volume of air into the engine’s intake system, thus increasing horsepower and fuel efficiency.

Variable Ratio Steering Rack:: The primary steering mechanism of a car consisting 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 are pitched and spaced closer together at each end of the rack.

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 that varies in height, creating downforce. Teams will use different sized wicker bills to create more or less downforce.