question: How do drag racers get grip at the beginning of a race by spinning tires?
comment: They burn out to heat up their tires and soften the rubber to make it more sticky. When they race they carefully control the throttle and clutch so that they are right at the edge of breaking their tires loose into a burnout but not quite. If they accidentally do burn out during a race they will lose unless their competitor makes a worse mistake
passages: Modern races are started electronically by a system known as a "Christmas tree", which consists of a column of lights for each driver/lane, and two light beam sensors per lane on the track at the starting line. Current NHRA trees, for example, feature one blue light (split into halves), then three amber, one green, and one red. When the first light beam is broken by a vehicle's front tire(s), the vehicle is "pre-staged" (approximately from the starting line), and the pre-stage indicator on the tree is lit. When the second light beam is broken, the vehicle is "staged", and the stage indicator on the tree is lit. Vehicles may then leave the pre-stage beam, but must remain in the stage beam until the race starts.
   Before each race (commonly known as a pass), each driver is allowed to perform a burnout, which heats the driving tires and lays rubber down at the beginning of the track, improving traction. The cars run through a "water box" (formerly a "bleach box", before bleach was replaced by flammable traction compound, which produced spectacular, and dangerous, flame burnouts; the hazard led NHRA to mandate use of water in the 1970s).
   Modern drag races are started electronically by a system known as a Christmas tree. A common Christmas tree consists of a column of seven lights for each driver or lane, as well as a set of light beams across the track itself. Each side of the column of lights is the same; from the top down, there is one blue LED light set arranged in a circle with a white line through the center, then three amber bulbs, then a green bulb and a red bulb. The light beams are arranged with one set on the starting line, and another set 7 inches behind it.
   In 1982, in a drag racing first, two women squared off in the Top Fuel final. Lucille Lee prevailed, and Shirley Muldowney was second best. This result prevented Muldowney from repeating as March Meet Top Fuel champion, as she had won the event the year before.
   When drivers are preparing to race, they first cross the beams 7 inches behind the starting line. Crossing this beam activates the top half of the circle. Once pre-staged, drivers roll up 7 inches and cross the second beam on the starting line, bottom half of the circle, including the crossing line. Once both drivers have crossed the staged sensor, an official starter or automatic starting system will activate the next lighting sequence.
   The first drag racing slick was developed by M&H Tires (Marvin & Harry Tires) in the early 1950s. It was the only company in the world that produced and sold original drag racing tyres.
   Push starts to get engines running were necessary until the National Hot Rod Association (NHRA) mandated self-starters in 1976. After burnouts, cars would be pushed back by crews; this persisted until NHRA required reversing systems in 1980. Don Garlits was the first to do burnouts across the starting line, which is now standard practise. Each driver then backs up to and stages at the starting line.
  
  Section::::Basics of drag racing.:Prerace preparations.
   Starting in 2016 for selected bracket races, CompuLink debuted the TruStart system for staggered start races. Prior to that, if the first driver left before the green, the light turned red automatically and the other driver was shown a green light, regardless of the infraction.
  
  Section::::Timing system manufacturers.
   In 2006, when the 12th lap is valid, the pilots will receive a checkered flag in green and yellow, which scores the first five places. At this point, the trail enters the Pace Truck, which neutralizes the race for cleaning and removal of vehicles on the track, staying three to five laps. After restart, trucks complete the preset number and make the podium in accordance with the classification in the race, plus the times of the penalties, if applicable.
   The Martelli Brothers featured a brand new event this year called the Method Race Wheels Pit Crew Challenge! Sixteen pit crews from the top unlimited truck teams competed in a head-to-head battle to decide who had the best crew. Each of the three-man teams were given one jack, one impact gun, and one spare tire. The team who completed two tire changes the fastest, advanced to the next round. Over 10,000 spectators on Fremont Street, showed up to cheer on the teams. After several close and heated rounds the General Tire/THR team – which included drivers Mikey Childress, Rick Johnson, and crewmember James Walker – out pitted the field to win the inaugural Method Race Wheels Pit Crew Challenge.
   "Wrinklewall" slicks are now specifically designed for the special requirements of drag racing, being constructed in such a way as to allow the sidewall to be twisted by the torque applied at launch, softening the initial start and thus reducing the chances of breaking traction. As speed builds, the centrifugal force generated by the tyre's rotation "unwraps" the sidewall, returning the energy to the car's acceleration. Additionally, it causes the tyres to expand radially, increasing their diameter and effectively creating a taller gear ratio, allowing a higher top speed with the same transmission gearing.
  
  Section::::Drag racing slicks.:Cheater slicks.
   Every year from spring until fall, the speedway hosts "Friday Night Drags" where participants drag race down the pit road. The racing is conducted on an 1/8-mile stretch and begins at the drop of a hand. No lights or timing tools are used.
   Based on a true story about two sisters who came out on top of a man's sport, the story is based on Courtney and Erica Enders, two sisters who get into junior drag racing and make it all the way to the top. The two sisters fight a battle of fellow racers who are against having girls race with them therefore it pushes them harder to compete against their competition. Erica becomes stressed when her racing life becomes mixed with her social life and academic goals, and decided to quit racing, until she realizes racing is what she truly wants to do. Finally towards the end of their teen years the Enders sisters come out on top to win the NHRA Junior Dragster national title. They continue to race throughout high school and college, and still do so today.
   BULLET::::- Rotary Club: Players from each team roll down an obstacle course while curled up inside of a giant tractor tire. If a tire stops short of the finish line with a player inside of it, one player designated as a tracker must push that tire across the finish line, and once that player has crossed the finish line, he/she has to push the tire uphill to a white line near the end zone, where teammates can help push the tire back to the beginning of the course. The process continues until each player has ridden inside of the tire down to the end zone and advanced the tire back to the beginning of the course, where the team that completes the challenge first wins.
   While real life NASCAR tracks are mainly ovals, "NASCAR Racers" is anything but. The racers compete on a wide variety of courses, including road course, off-road, mountain, and Motorsphere. The Motorsphere track starts with a typical race track leading into a sphere, then tracks are wrapped around the inner surface of the sphere, which look like the AcceleDrome track from "AcceleRacers".
   In April 1970, Mark Williams' car, built for Mike Dollins and Dan Widner (at a cost of only US$2,111.16), first appeared; its wheelbase was significantly longer than the usual for fuellers at the time. The car ran well, but required new driving techniques; Dollins and Widner lacked the money to continue racing it, and it was sold to a Colorado team, which switched to a hemi (rather than the usual .
   Since 1984, the NHRA officially uses CompuLink timing systems at venues on their professional drag racing circuit (includes the Christmas Tree, control units, timing sensors, cables, program software and time slip printer). Many divisional tracks for both the NHRA and IHRA also use CompuLink, but current timing system manufacturers of similar operations including Accutime, TSI, PortaTree and RaceAmerica among others can be seen at various drag strips throughout the world so long as these timing systems comply to rules and regulations set forth by the respective drag racing organizations for which they are members. There are still a few drag strips which continue to use the much older Chrondek timing system, although the company was sold to Daktronics in the 1980s and parts for that system are no longer made. Most drag racing time scoreboards currently seen at the tracks are provided by Daktronics, RaceAmerica or Accutime.
   BULLET::::- Episode 5: Team Trans Am thinks they have lost their transmission after running over a bump. The bump causes a fluid line to be torn loose. This is quickly repaired, and they are able to return to the road.
  
  BULLET::::- Episode 6: Team F-150 competes against Team Lotus in the Challenge, which is a drag race with a concrete wall at the end if the cars don't stop in time. Team F-150 chooses to crash through this wall, resulting in damage to their headlights and grille. They are able to repair the damage and continue.
   To get the "go", jump, break, hit, kick, or move is to start the race without the flagger. This is another system of handicapping that requires one car to wait until they see the other car start to move before they are allowed to leave their starting line. In legitimate drag strips that run street racing style events, a jump is used for a red light foul if the Christmas Tree is used.
   Based in Phoenix, Arizona, West ran the Chevrolet-powered "Wild Wild West" AA/FA; his brother, Johnny, ran a similar car in the middle 1970s.
  
  Leon Fitzgerald and Jack Eskelson collaborated on a '48 Topolino altered, powered by an injected Chevrolet; they would later add a supercharger, leading to a best time of 9.55 at .
   The UEM also has a different structure of professional categories with Top Fuel Bike, Super Twin Top Fuel Bike, and Pro Stock Bike contested, leaving the entire European series with a total of 8 professional categories.
  
  To allow different cars to compete against each other, some competitions are raced on a handicap basis, with faster cars delayed on the starting line enough to theoretically even things up with the slower car. This may be based on rule differences between the cars in stock, super stock, and modified classes, or on a competitor's chosen "dial-in" in bracket racing.
   Section::::Basics of drag racing.:Measurements.
  
  Several measurements are taken for each race: reaction time, elapsed time, and speed. Reaction time is the period from the green light illuminating to the vehicle leaving the staging beams or breaking the guard beam. Elapsed time is the period from the vehicle leaving the starting line to crossing the finish line. Speed is measured through a speed trap covering the final to the finish line, indicating average speed of the vehicle in that distance.
   BULLET::::- Top Sportsman (NHRA, IHRA, ANDRA) Competitors in these full-bodied entries may choose their own dial-in for eliminations, generally from 6.00 to 7.99 seconds. Full Tree starts are used, and the breakout rule is enforced. Cars can run in the sixes at more than .
   There was crossover between classes. For instance, Dan Parker turned a Logghe ex-Funny Car chassis, with a fiberglass reproduction Bantam body, into a B/Econo Altered for racing in Competition Eliminator.
  
  In an effort to tame notoriously bad handling, with cars frequently wheelstanding or sideways, engine-mounted wings were state of the art in the 1960s, appearing on, among others, "Yellow Submarine", run by Hunter-Lewis-Perry; driven by Tim Perry, it turned in a best pass of 7.19 at .
   Most race events use a traditional bracket system, where the losing car and driver are eliminated from the event while the winner advances to the next round, until a champion is crowned. Events can range from 16 to over 100 car brackets. Drivers are typically seeded by elapsed times in qualifying. In bracket racing without a breakout (such as NHRA Competition Eliminator), pairings are based on times compared to their index (faster than index for class is better). In bracket racing with a breakout (Stock, Super Stock, but also the NHRA's Super classes), the closest to the index is favourable.
  