AERO PUSH -- When following another vehicle closely, the airflow off the lead vehicle does not travel across the following one(s) in a normal manner. Therefore, downforce on the front of the trailing vehicle(s) is decreased and it does not turn in the corners as well, resulting in an "aero push." This condition is more apparent on the exit of the turns.

AERODYNAMIC DRAG -- A number that is a coefficient of several factors that indicates how well a race vehicle will travel through the air and how much resistance it offers. Crewmen work to get the best "drag horsepower" rating they can, determining how much horsepower it will take to move a vehicle through the air at a certain mile-per-hour rate. At faster speedways teams strive to get the lowest drag number possible for higher straightaway speeds.

AERODYNAMICS -- This crucial aspect of racecar design and tuning defines how the car moves through the air and how areas of high and low pressure can be generated and manipulated to maximize down force while minimizing drag.  In Formula cars, this includes the airflow underneath the car, generally referred to as "ground effects." 

AIR DAM -- A strip that hangs under the front grill, very close to the ground. It helps provide downforce at the front of the car.

AIR PRESSURE -- With the advent of radial tires with stiffer sidewalls, changing air pressure in the tires is used as another setup tool that is akin to adjusting spring rates in the vehicle's suspension. An increase in air pressure raises the "spring rate" in the tire itself and changes the vehicle's handling characteristics. If his race vehicle was "tight" coming off a corner, a driver might request a slight air pressure increase in the right rear tire to "loosen it up."

ANTI-ROLL BAR -- This is a mechanical linkage, set up for both the front and rear suspension, that helps keep the car from "rolling over" in the corners.  This complex linkage helps keep all four tires gripping the track, and is adjustable by the driver using levers within the cockpit.  Also called a sway bar. 

APEX -- The geometric center of a corner. In racing, a driver will often use a "late apex," turning into the corner a little later than normal in order to straighten out the last part of the corner.  This allows the driver to accelerate earlier and harder, gaining maximum speed down the subsequent straightaway.

BACK MARKER -- A car running off the pace near the back of the field. 

BALACLAVA -- The fireproof hood that most drivers wear under their helmets to avoid burns to their face and neck.

BALANCE -- When a car doesn't tend to oversteer or understeer, but goes around the racetrack as if it's on rails, the car is said to be in balance.

BANKING -- On oval tracks, the corners are often tilted inwards to provide higher speeds. On some road courses, certain turns may actually be banked outward, a very difficult type of corner known as "off-camber." The sloping of a racetrack, particularly at a curve or a corner, from the apron to the outside wall. Degree of banking refers to the height of a racetrack's slope at the outside edge. 

BLACK FLAG -- This flag is used by the starter to signal a driver that he must immediately report to the pits for consultation related to a dangerous mechanical condition or a driving infraction.  Failure to heed the flag can result in exclusion from the final results of the event.  This flag may be displayed in a "furled" (rolled up) manner as a warning.  Corner workers may also display a black flag if the session has been halted by the display of a red flag by the starter. 

BLUE FLAG -- This flag is used by corner workers around the track to signal a driver that a faster car is either approaching (steady flag) or actually attempting a pass (waved flag).  The driver being flagged has no obligation to do anything other than be alert, maintain the racing line and avoid intentionally obstructing the faster car. 

BODYWORK -- The exterior of the car.  The bodywork is generally made from lightweight carbon fiber and is made to come apart in sections, providing access to certain mechanical components.  Bodywork is carefully sculpted to maximize aerodynamic efficiency.

BRAKE BIAS -- In most cars, including street cars, pressing on the brake pedal applies a little more force to the front brakes than the rear.  This is designed to take advantage of the fact that under braking, weight transfers to the front of the car.  With lots of weight on the front tires, the brakes can be applied very hard without completely stopping the wheels from rotating.  At the same time, the rear of the car tends to get lighter so the rear brakes must be engaged less strongly than the fronts to avoid locking the wheels and possibly losing control.  In a racecar, brake bias is adjustable by the driver to compensate for changing conditions. 

BRAKE FADE -- When the fluid in the brake system exceeds its boiling point due to hard use, bubbles can form in the brake lines and calipers. Since these bubbles can be squeezed smaller by pressure from the brake pedal, the pedal tends to "go soft" and may even go to the floorboard without the brakes working properly. 

BUMP -- In shock absorbers, a bump adjustment is a change to the dampening of the shock on the compression stroke.  As a car passes over a bump on the track, each wheel assembly rises up to pass over it.  Without compression dampening, the inertia of the wheel assembly would cause it to continue to rise after the bump until the spring finally overcomes the inertia and pushes the wheel back down.  Since a tire can't do any work while in the air, bump dampening stops the upward inertia and allows the tire to stay in constant contact with the pavement.  Bump adjustments can also affect how the weight of the car shifts around during braking, acceleration and cornering. 

CAMBER -- An element of chassis tuning.  Camber addresses the angle at which a tire makes contact with the track surface. Each tire can be tilted inwards or outwards depending on the track.  The usual idea is to tilt the top of the tire inwards (negative camber) so that under cornering loads, the entire surface of the tread is being used to the maximum.  On oval tracks, since the car only turns left the left-side tires may actually be tilted outwards (positive camber).  Teams adjust the camber setting based on reading tire temperatures across the surface of the tread, with the goal of having equal temperatures on the inside, middle and outside edges.  This temperature equilibrium indicates the tire is being used to its maximum capacity. 

CAMSHAFT -- A rotating shaft within the engine that opens and closes the intake and exhaust valves in the engine.

CART -- Championship Auto Racing Teams. 

CASTER -- Another element of chassis tuning related to the front wheels.  The front wheels are attached to the suspension at the top and bottom of the wheel assembly.  The top attachment is typically set a little farther back than the lower attachment, creating caster.  The more caster used, the more the wheel resists turning forces, providing stability.  Too much caster makes it very difficult to steer and causes the tire camber to change excessively as the wheel is turned. 

CATCH FENCE -- At most oval tracks, or in any place where the crowd is close to the track, catch fences are used to stop cars and car parts from flying into the crowd in the event of a crash.  One of the most dangerous flying parts in a crash are the wheel assemblies, which can bounce very high. 

CAUTION PERIOD -- When an accident happens, or for other reasons such as debris on the track or a sudden downpour, the officials may put the track under caution by waving yellow flags at the starter stand and around the track.  This brings out the pace car to gather the field and lead them around at reduced speed until the time for a restart. 

CHAMP CAR -- In the early days of open-wheel racing, this term was used to differentiate the cars actually participating in the National Championship from other types of open wheel racing.  This popular terminology has been re-adopted for the CART FedEx Championship in 1998 and beyond. 

CHASSIS -- The basic structure of a car, including the driver tub, gearbox, and suspension.  Engines are provided separately. 

CHASSIS ROLL -- The up-and-down movement caused when a car travels around corners at high speeds. The said of the car facing the turn becomes lighter while the extra wight goes toward the outside of the turn.

CHECKERED FLAG -- This black-and-white checked flag is the most famous in racing, signifying the end of the session or race. At the end of a race, the first car to receive the checkered flag at the finish line is the winner. 

CHICANE -- A quick succession of opposite-direction turns, usually intended to reduce excessively-high straightaway speeds. 

COMPOUND -- Compound refers to the chemical composition of the rubber tread, which requires a balance between the conflicting goals of traction and long wear. 

CORNER WEIGHTS -- This refers to the distribution of a car's weight among the four wheels.  Management of these corner weights is very important to handling.  This weight is usually adjusted through raising and lowering each corner by rotating a threaded spring perch on each shock absorber. 

CORNER WORKERS -- The quiet heroes of racing.  These volunteer workers will travel across the country at their own expense, eating peanut butter sandwiches and sleeping in tents to provide flagging and marshalling duties around the track.  Their expertise is one of the keys to the tremendous safety record of Formula racing, and the drivers waving to the corner workers at the end of an event it is a reflection of their acknowledgement of the contribution these great people make.  If you are interested in getting involved in this sport, volunteering for training at club racing events around the country is a great way to get immersed in the action.  

CONTACT PATCH -- The part of the tire that actually touches the track.

DATA ACQUISITION -- Racing teams use sophisticated sensors and software to provide information on what the car is doing.  Everything from engine stress to steering wheel position can be monitored. This information is analyzed to provide a basis for improvements to handling, performance and even driver technique. This data acquisition can be accomplished by connecting a computer to the car or by use of wireless telemetry.

DIFFUSER -- This piece of bodywork is underneath the rear of the car and is intended to manage airflow as it exits.  A good diffuser design can generate significant down force.

DIRTY AIR -- At high speeds, down force on the front wings can be disrupted by following closely behind another car.  The rear wing of the car in front tends to push the air higher, creating a very turbulent low-pressure area directly behind the car.  A car following closely often will suffer understeer as a result of being in this "dirty air." 

DOWN FORCE -- The wings on a Formula car are set up opposite from an airplane.  Instead of providing lift, they are used to press the car harder onto the track providing increased traction for braking, acceleration and cornering.  Down force is also provided by the ground-effects tunnels on each side of the car.  A modern Formula car provides so much down force that it could actually stick to the ceiling at just over 120 miles per hour.  Increased down force also results in increased drag, so a tradeoff is required. In a Stock car,  the air pressure traveling over the surfaces of a race vehicle creates "downforce" or weight on that area. In order to increase corner speeds teams strive to create downforce that increases tire grip. The tradeoff for increased corner speeds derived from greater downforce is increased drag that slows straightaway speeds.

DRAFTING -- A fast-moving car creates a low pressure area behind it, causing the air to try and move with the car.  A car following behind can take advantage of this low pressure as it actually sucks the car along faster, known as "being in the slipstream."  A savvy driver can either use the draft to pass or to lift off the gas slightly and conserve fuel. 

DRAG -- The resistance a car experiences when passing through air at high speeds. A resisting force exerted on a car parallel to its air stream and opposite in direction to is motion.

DYNO -- A condensation of "Dynamometer," a device used to test an engine in the shop by simulating the loads and environment a racing engine encounters.

ENGINE BLOCK -- An iron casting from the manufacturer that envelopes the crankshaft, connecting rods, and pistons. 

FABRICATOR -- A person who specializes in creating the sheet metal body of a stock car. Most temas employ two or more.

FIREWALL -- A solid metal plate that separates the engine compartment from the driver's compartment of a racecar.

FLAGS -- Flags are used to signal drivers of events or conditions.  Flags used in racing include green, white, white and red, black, checkered, blue, yellow, red and red/yellow.  See each individual color for an explanation of what each flag means. 

FLAT SPOT -- If a driver locks a tire (brakes so hard that the wheel stops turning entirely), a flat spot will be created on the surface of the tire. This can create a vibration so bad that the car is almost undriveable. 

FORMULA CAR -- Formula car is a term to define open-wheeled racecars that must fit within a specific set of design rules or "formula."  The formula for open-wheel cars is quite complex, but basic issues include minimum weight, engine displacement, vehicle dimensions, wing sizes and placement, ground-effects tunnel size and configuration, tire and wheel size and safety considerations.

FRONT CLIP -- The front-most part of the racecar, starting with the firewall. 

FUEL CELL -- A holding tank for a racecar's supply of gasoline. Consists of a metal box that contains a flexible, tear-resistant bladder and foam baffling. A product of aerospace technology, it's designed to eliminate or minimize fuel spillage.

GEARBOX -- Refers to the transmission attached to the rear of the engine.  The new Swift chassis integrates a "sequential" shift pattern, which is more like a motorcycle gear change than the traditional "H" pattern we all use on our street cars. 

GREEN FLAG -- The green flag is used by the starter to signal drivers that the race is underway, either at the start of the event or at the conclusion of a full-course yellow flag condition. 

GRID -- The starting order of cars, as determined by qualifying position. 

GROOVE -- Slang term for the best route around a racetrack; the most efficient or quickest way around the track for a particular driver. The "high groove" takes a car closer to the ouside wall for most of a lap, while the "low groove" takes a car closer to the apron than the ouside wall. Road racers use the term "line." Drivers search for a fast groove, which has been known to change depending on track and weather conditions.

GROUND EFFECT -- This describes the nature of airflow near the ground.  In airplanes, this refers to a cushion of air that builds up as a plane nears the ground.  In racecars, this refers to artificially-generated low-pressure areas underneath the car which help it adhere to the ground.  This is done by use of three-sided ground-effect 'tunnels' on each side of the bottom of the car, which start off small near the front and gradually get bigger towards the rear, creating a vacuum as the car moves forward using the ground as the fourth side of the tunnel.  This is carefully managed by teams, using rules which specify the dimensions of the tunnels and how high the outside edge of each tunnel must be from the ground. The greater the gap between the tunnel side and the ground, the more vacuum escapes and the less down force is generated. 

GURNEY FLAP -- On the front and rear wings of a Formula car, there are often small vertical strips set at 90 along the trailing edges of the wings, set at 90 degrees to the plane of the wing.  These flaps provide significant down force with a minimal amount of drag by greatly reducing turbulent air behind the wing.  On the rear wing it can be easily exchanged for a flap of different size during a pit stop.  CART team owner Dan Gurney is generally attributed with creating this device, which is also known as a "wickerbill." 

HAIRPIN -- A sharp, 180 degree turn.

HANDLING -- Generally, a racecar's performance while racing, qualifying, or practicing. How a car "handles" is determined by its tires, suspension geometry, aerodynamics, and other factors.

HAPPY HOUR -- Slang term for the last official practice session held before an event. usually takes place the day before the race and after all qualifying and support races have been staged. 

HEAT CYCLE -- A tire that has been heated up through use and then cooled down has experienced one heat cycle.  This often results in a slight hardening of the tire compound, which can make the tire perform at a high level for a longer period of time.  See Scrubbed Tires. 

HORSEPOWER -- A measure of an engine's maximum output in terms of torque over a period of time.  A typical medium-sized family sedan produces around 150 horsepower to move 3,000 pounds. 

INFIELD -- The portion of a racing facility that lies inside the boundary of the track. 

INTERVAL -- The time-distance between two cars. Referred to roughly in car lengths, or precisely in seconds.

KEVLAR -- A brand name for a certain type of carbon fiber, used in everything from driver's helmets to bodywork to the bullet-proof vests used by police.  A very strong and lightweight material. 

KITTY LITTER -- This term describes two things: the absorbent powder used to soak up fluid spills on the track (often actual kitty litter) and the gravel runoff areas on the outside of certain road course turns used to slow cars that go off the track. 

LAPPED TRAFFIC -- Cars that have completed at least one full lap less than the race leader.

LINE -- This is the quickest way around a race circuit, taking advantage of braking, cornering and acceleration techniques.  For example, the line for a typical right-handed corner would involve lining up on the left side of the approaching straight, braking hard, turning in all the way across the track to the inside curb, and then unwinding the steering wheel on the exit to release the friction of the turn, which takes the car back across the track to the outside again.  The idea is to use the maximum amount of arc possible to maintain the greatest speed through the corner.  The line is often visible due to the rubber laid down by cars, and interestingly is not the shortest way around the track, just the fastest. 

LOOSE -- (Also referred to as "free" or "oversteer.") Typically describes a cornering condition where the rear tires lose adhesion before the front tires, resulting in a car that feels like it wants to spin easily.  This is one of the most unpleasant sensations for a driver at high speed.  Solutions include adjustments to tire pressure, increasing the angle of the rear wing to press the tires harder to the ground, softening the rear anti-roll bar setting or spring rates in order to provide more grip, or by making changes to reduce grip at the front such as reducing the front wing angle or stiffening the front anti-roll bar setting or spring rates.  Here is an easy way to remember whether a car is loose (oversteer) or tight (understeer), as originally described by Bobby Unser, "If the front end hits the wall, it's understeer.  If the rear end hits the wall, it's oversteer." 

MARBLES -- Bits of rubber are scrubbed off of racing slicks while cornering.  These small balls collect on the outside of the turn, and if a car goes wide (into the marbles, or into "the gray," referring to the lighter appearance of an area covered with marbles) then much adhesion is lost.  This often can cause a car to understeer straight into the wall or off the track.  With the tire competition between Goodyear and Firestone leading to softer and softer tire compounds, marbles are more of a problem.  Organizers use street sweepers to clean these marbles off the track whenever possible. 

NASCAR -- National Association Stock Car Auto Racing.

NOMEX -- A fire and heat-resistant material used to make driving suits, gloves, shoes, helmet liners, balaclavas and underwear.  Most drivers wear four or five layers of Nomex, which can provide as much as a minute of complete fire protection.  When combined with fuel bladders that are resistant to breaking open in a crash, the risk of fire has been greatly reduced over the last 20 years.  Much of this technology was developed by the military. 

NEUTRAL -- A term drivers use when referring to how their car is handling. When a car is neither loose nor pushing (tight).

OPEN WHEEL -- Refers to any type of race car that does not have enclosed wheels. CART, Formula Atlantic, and Indy Lights are open wheel cars, as are the sprint cars, midgets, and modifieds that run at local Saturday night tracks all over North America.  Stock cars and sports cars are typically based more closely on production cars with the wheels enclosed within fenders. 

OVAL TRACK -- Used to describe tracks with a layout that incorporates some version of a circle, usually with a rectangular, triangular or oblong shape, and incorporating either banked or flat turns. 

OVERSTEER -- Same as Loose.  Typically describes a cornering condition where the rear tires lose adhesion before the front tires, resulting in a car that feels like it wants to spin easily.  This is one of the most unpleasant sensations for a driver at high speed.  Solutions include adjustments to tire pressure, increasing the angle of the rear wing to press the tires harder to the ground, softening the rear anti-roll bar setting or spring rates in order to provide more grip, or by making changes to reduce grip at the front such as reducing the front wing angle or stiffening the front anti-roll bar setting or spring rates.  Here is an easy way to remember whether a car is loose (oversteer) or tight (understeer), as originally described by Bobby Unser, "If the front end hits the wall, it's understeer.  If the rear end hits the wall, it's oversteer." 

OFF-CAMBER -- Some turns on road and street courses are actually banked outwards, which can make them very tricky to negotiate.  This is known as an off-camber turn. 

PADDOCK -- The area where the team transporters are located, and where the teams work on the cars between on-track sessions.  This area is usually accessible to the general public. 

PIT ROAD -- The area where cars come in for fuel, tires, adjustments, and repairs during on-track sessions.  The name originated from early race tracks, where the mechanics actually stood in a shallow pit where they could duck if an out-of-control car came their way.  Today, mechanics are protected by concrete walls and the lane is segregated from the actual racing surface. 

POLE POSITION -- This historic term refers to the driver who starts at the front of the field on the inside of the front row by virtue of the fastest qualifying time.  The term originated at horse tracks, where many of the original Champ Car races were held on dirt.  The finish and distance markers of a horse track are marked by poles set on the inside edge of the track.

PUSH -- Same as Understeer or Tight.  Typically describes a cornering condition where the front tires lose adhesion before the rear tires, resulting in a car that feels like it wants to go straight.  Solutions include adjustments to tire pressure, increasing the angle of the front wings to press the tires harder to the ground, softening the front anti-roll bar setting or spring rates in order to provide more grip, or by making changes to reduce grip at the rear such as reducing the rear wing angle or stiffening the rear anti-roll bar setting or spring rates.  Here is an easy way to remember whether a car is loose (oversteer) or tight (understeer), as originally described by Bobby Unser.  "If the front end hits the wall, it's understeer.  If the rear end hits the wall, it's oversteer."  

QUALIFYING -- Qualifying determines starting positions, and usually consists of the combined results from two on-track sessions.  Each car is timed, and the starting grid is determined by the order of fastest cars.  For road and street courses, all the cars are on the track at the same time which requires careful management of track position in order to avoid being blocked by a slower car.  For oval events qualifying is one car at a time, usually for two timed laps.  

QUARTER PANEL -- The sheet metal on both sides of the car from the C-post to the rear bumper below the deck lid and above the wheel well.

RAIN TIRES -- Treaded tires used on a wet track.  Also referred to as "Wets."

RAKE -- Most race cars are slightly lower at the front than at the rear.  This provides for a natural "ground effects" tunnel under the car, and can also be adjusted to change the weight distribution between the front and rear wings. 

REAR CLIP -- The section of a racecar that begins at the base of the rear windshield and extends to the rear bumper. Contains the car's fuel cell and rear suspension components.

REBOUND -- In shock absorbers, a rebound adjustment is a change to the dampening of the shock on the expansion stroke.  Without rebound dampening, the car would tend to bounce as it passes over bumps on the track.  Rebound adjustments can also affect how the weight of the car shifts around during braking, acceleration and cornering. 

RED FLAG -- This flag, when displayed at the start/finish line, signifies an immediate halt of the session due to a major problem such as heavy rain or an accident that is blocking the track.  Corner workers around the track will display black flags when this happens, and all cars are required to stop racing and slowly return to the pits. The lap in progress is discarded, and the field results to the order of the previous lap when racing resumes. I f the race has run more that 50% of the laps, the chief steward has the option to declare a complete race if track conditions are not expected to improve.  If a race has run less that 50%, it will be concluded on another date. 

RED AND YELLOW FLAG -- This striped flag is displayed by corner workers to signify debris on the track, which can be oil, sand, water, or some other substance. 

RESTRICTOR PLATE -- An aluminum plate that is placed between the base of the carburetor and the engine's intake manifold with four holes drilled in it. The plate is designed to reduce the flow of air and fuel into the engine's combustion chamber, thereby decreasing horsepower and speed.

RIDE HEIGHT -- This refers to the height of the chassis above the ground.  Because of the relationship between the height of the ground effect tunnels and their performance, maintaining optimum ride height is an important feature of car setup and design.  However, it is hard to manage since the faster a car goes, the more the aerodynamic effects press it to the ground.  Many very complex methods are used to maintain a consistent ride height. 

ROOF FLAPS -- These flaps are sections at the rear of a race vehicle's roof that are designed to activate, or flip up, if the air pressure flowing across them decreases. In the case of a vehicle turning backwards, the tendency for an uninterrupted flow of air is to create lift. The roof flaps are designed to disrupt that airflow in attempt to keep the vehicle on the ground.

ROUND -- Slang term for a way of making chassis adjustments utilizing the stock-car's springs. A wrench is inserted in a jack bolt attached to the springs, and is used to tighten or loosen the amount of play in the spring. This in turn can loosen or tighten the handling of a racecar.

SCRUBBED TIRES -- Also known as Scuffed Tires.  Tires that have a few laps on them to remove the outer sheen and provide more consistent traction.  See Heat Cycles. 

SETUP -- There are a huge number of variable adjustments which can be made to racecar to improve the handling and performance.  The driver with the best setup is in a good position to win.  A driver with a less than perfect setup can sometimes "hustle the car" and compensate for the deficiency, but most drivers perform at their utmost only when the car is comfortable.

SHORT TRACK -- Racetracks that are less than one mile in length. 

SHUNT -- British term for crash or accident.

SILLY SEASON -- Slang for the period that begins during the latter part of the current season, wherein some teams announce driver, crew, and/or sponsor changes. 

SLICKS -- A racing tire with no tread.  There is a misconception that the tread pattern of a tire provides traction.  This is true in dirt, snow or on wet pavement, but on dry pavement the maximum amount of "contact patch" is desirable. 

SLIPSTREAM -- See Drafting. 

SPOILER -- (Also referred to as a "blade.") The spoiler is a strip of aluminum that stretches across the width of a race vehicle's rear decklid. It is designed to create downforce on the rear of the vehicle, thereby increasing traction. However, the tradeoff, again, is that more downforce equals more aerodynamic drag, so teams attempt, particularly on qualifying runs, to lay the spoiler at as low an angle as possible to "free up" their vehicles for more straightaway speed.

SPOTTERS -- Teams on an oval track will usually have a crew members on top of the grandstand, where they can see the entire track and warn drivers of an accident or advise them where to go in traffic. 

STAGGER -- Stagger is a concept that has largely been eliminated with the use of radial tires. It refers to the difference in tire circumference between the left- and right-side tires on the vehicle. Typically, the left-side tires would be a smaller circumference than the right-side tires to "help" the vehicle make left-hand turns.

STICK -- Slang term used for tire traction.

STICKERS -- A brand new tire, with the manufacturer's sticker still on the tread. 

STOP 'N' GO -- (black-flagged) A penalty, usually assessed for speeding on pit road at the appropriate speed and stopped for one full second in the team's pit stall before returning to the track.

SUPERSPEEDWAY -- A racetrack of one mile or more in distance. Road courses are included. Racers refer to three types of oval tracks. Short tracks are under one mile, intermediate tracks are at least a mile but under two miles, and superspeedways are two miles and longer.

SWAY BAR -- Sometimes called an "antiroll bar." Bar used to resist or counteract the rolling force of the car body through the turns.

TAKE A LOOK -- A driver following closely behind another car may dart momentarily to the inside of the entry to a corner, pretending to attempt a pass in order to disrupt the concentration of the driver in front and hopefully causing a small mistake. 

TELEMETRY -- The portion of data acquisition that is transmitted wirelessly while the car is on the track. 

TEMPLATE -- A device used to check the body shape and size to ensure compliance with the rules. The template closely resembles the shape of the factory version of the car.

TIGHT -- Same as Push or Understeer.  Typically describes a cornering condition where the front tires lose adhesion before the rear tires, resulting in a car that feels like it wants to go straight.  Solutions include more front wing to press the tires harder to the ground, softening the front anti-roll bar setting or spring rates in order to provide more grip, or by making changes to reduce grip at the rear such as reducing the rear wing angle or stiffening the rear anti-roll bar setting or spring rates.  Here is an easy way to remember whether a car is loose (oversteer) or tight (understeer), as originally described by Bobby Unser. "If the front end hits the wall, it's understeer.  If the rear end hits the wall, it's oversteer." 

TOE -- In order to provide stable tracking, all four tires are usually pointed slightly inwards if viewed from overhead.  More toe-in provides more stability but increased tire drag.  On high-speed oval tracks, these toe settings are even more crucial.  Toe-out may be used in certain types of cars and situations, but toe-in is more common.  Teams usually adjust toe with the most unsophisticated methodology seen in racing, using a string around the outside of the car and a caliper to measure the difference in the distance from the string between the front outside of the tire and the rear outside of the tire. 

TORQUE -- A measure of engine power, described in foot/pounds of force.  10 foot/pounds of torque would raise ten pounds of weight one foot in the air.  Horsepower is a measurement of torque over a period of time.

TRACK BAR -- (Also referred to as a "Panhard bar.") This bar locates the stock car's rear end housing from left-to-right under it. In calibrating the vehicle's "suspension geometry," raising or lowering the track bar changes the rear roll center and determines how well it will travel through the corners. During races, this adjustment is done through the rear window using an extended ratchet. Typically, lowering the track bar will "tighten" the vehicle and raising the track bar will "loosen" it.

TRAILING ARM -- A rear suspension piece holding the rear axle firmly fore and aft yet allowing it to travel up and down.

TRI-OVAL -- A racetrack that has a "hump" or "fifth turn" in addition to the standard four corners. Not to be confused with a triangle-shaped speedway, which only has three distinct corners.

TUNNELS -- Ground effect-generating areas underneath the sides of an Formula car. 

TURN IN -- As a car reaches a corner, this is the moment at which a driver actually begins to turn the wheel.  The timing of this action and the car's response to it are crucial for setting fast lap times. 

TURBULANCE -- Air that trails behind a racecar and disrupts the flow of air to the cars behind it.

UNDERSTEER -- Same as Push or Tight.  Typically describes a cornering condition where the front tires lose adhesion before the rear tires, resulting in a car that feels like it wants to go straight.  Solutions include more front wing to press the tires harder to the ground, softening the front anti-roll bar setting or spring rates in order to provide more grip, or by making changes to reduce grip at the rear such as reducing the rear wing angle or stiffening the rear anti-roll bar setting or spring rates.  Here is an easy way to remember whether a car is loose (oversteer) or tight (understeer), as originally described by Bobby Unser.  "If the front end hits the wall, it's understeer. If the rear end hits the wall, it's oversteer." 

VALANCE -- (Also referred to as "front air dam.") This is the panel that extends below the stock car's front bumper. The relation of the bottom of the valance, or its ground clearance, affects the amount of front downforce the vehicle creates. Lowering the valance creates more front downforce.

VICTORY LANE -- Sometimes called the "winner's circle." The spot on each racetrack's infield where the race winner parks for the celebration.

VORTEX -- An area of revolving compressed air.  The most obvious examples are the vortices that are visible coming off the rear wing of a racecar in humid conditions. 

WEDGE -- Refers to the relationship from corner-to-corner of the weight of the race vehicle. Increasing the weight on any corner of the vehicle affects the weight of the other three corners in direct proportion. Weight adjustments are made by turning "weight jacking screws" mounted on each corner with a ratchet. A typical adjustment for a "loose" car would be to increase the weight of the left rear corner of the vehicle, which decreases the weight of the left front and right rear corners and increases the weight of the right front. A typical adjustment for a "tight" vehicle would be to increase the weight of the right rear corner, which decreases the weight of the right front and left rear and increases the weight of the left front.

WEIGHT JACKING -- The practice of shifting a car's weight to favor certain wheels.

WHITE FLAG -- When used by the starter, this signifies the last lap of the race.  When used by a corner worker, it signifies that a slow-moving vehicle is on the track. 

WHITE AND RED FLAG -- Used by the starter, this white flag with a diagonal red stripe indicates to the field that an emergency or service vehicle is on the track, and extreme caution should be used.

WICKERBILL -- Same as Gurney Flap.  On the front and rear wings of an Formula car, there are often small vertical strips set at 90 along the trailing edges of the wings, set at 90 degrees to the plane of the wing.  These flaps provide significant downforce with a minimal amount of drag by greatly reducing turbulent air behind the wing.  On the rear wing it can be easily exchanged for a flap of different size during a pit stop.  CART team owner Dan Gurney is generally attributed with creating this device.  

WIND TUNNEL -- A structure used by race teams to determine the aerodynamic efficiency of their vehicles, consisting of a platform on which the vehicle is fixed and a giant fan to create wind currents. Telemetry devices determine the airflow over the vehicle and its coefficient of drag and downforce.

YELLOW FLAG -- If displayed by a corner worker, this means the subsequent section of the track has a problem that requires that drivers slow down and not make any passes.  Usually this arises because a car has crashed and is in a dangerous position. If the starter displays two yellow flags, it signifies a full-course caution which prompts the pace car to enter the track and lead the cars around at reduced speed.