What is IndyCar?
- therookiereporters
- Aug 22
- 8 min read
Have you ever heard of IndyCar? Whilst you’re more likely to have if you are from America, do you really know what the championship is all about?
IndyCar is the premier open-wheel racing series in North America. Indycar made its debut in 1909 but it wasn’t officially a series till 1996. It features high-speed races on different types tracks. These are short ovals, road courses, superspeedways and street circuits. What makes these tracks different from each other?
Short ovals:
Smaller oval tracks that offer close wheel-to-wheel action.
Road courses:
Tracks with a mix of turns and straights, similar to the traditional Formula One tracks like Silverstone.
Superspeedways:
High-speed oval tracks like the Indianapolis Motor Speedway, where racing can reach 230mph.
Street circuits:
Temporary circuits are set up on city streets .
Technical specifications
Indycar currently allows manufacturers to develop different engines; Honda and Chevrolet are the two engine producers for teams. However, every team is permitted the same chassis built by Dallara.
Chassis: 1996-2011
In the first season, the CART chassis was built by Lola and Reynard; however, Tony George deemed it inaccessible and specified new technical regulations for less expensive cars and production-based engines. This essentially outlawed the use of CART chassis and turbocharged engines.
In 2003, the rules were changed to require chassis manufacturers to be approved by the league before they could build a car. Before this, a party could build a car in the rules and sell it at the league-mandated price.
Dallara began producing chassis in 1997, and it was evenly matched to the G Force chassis in the first few seasons. Slowly, Dallara began to win more races, which caused an influx of customer teams. As of the time of writing, the Dallara chassis has won the Indy 500 26 times, its first victory being with Eddie Cheever in 1998.
The mentioned G Force chassis, also introduced in 1997, won the 1997 and 2000 Indy 500. In 2002, Elan Motorsport Technologies purchased and renamed G Force to Panoz G Force. It then got back-to-back victories at the Indy 500 in 2003 and 2004. The following year, it was a runner-up in the race. By 2008, there was only one Panoz driven by Phil Giebler; they then decided to pull out of the sport.
Riley & Scott were producers from 1997 to 2000. It was purchased by Renard, who produced the Mark VII that won in Phoenix 2000.
Chassis: 2012-2014
2 years earlier, IndyCar announced the adoption of a single-make chassis formula for 2012. That July, it was revealed that Dallara would be the manufacturer for IndyCar chassis, costing $349,000 per chassis.
Chassis: 2015-2017
Due to the teams now being restricted in the choice of chassis, they began to include aero kits from their engine manufacturers. While these kits increased speed and further differentiated each manufacturer, they also increased the costs. Chevrolet’s kits outperformed those of Honda and IndyCar decided to allow teams to shop for competitively priced non-safety-related parts like brakes while they all had the same aero kits in 2018, as a means to reduce costs.
Chassis: 2018-present
Beginning in 2018, all of the cars were equipped with the UAK18 bodywork. This ensured a decrease in the number of smaller aerodynamic components to become dislodged or broken, thus decreasing the potential debris ending up on the race tracks that can cause punctures the need for repairs. In 2020, we saw the introduction of the aeroscreen (a safety feature) and other minor changes to the car’s chassis.
Planned replacement
On March 5, 2024, plans for a successor to the Dallara DW12 chassis were publicly discussed, noting its age. On December 16, 2024, IndyCar announced wind tunnel testing of the new Dallara IR-27 chassis, expected to début in the 2027 season, based on Formula One car aerodynamics. On June 12, 2025, the planned chassis was delayed to 2028 and renamed Dallara IR-28.
Turbochargers
Turbochargers returned to IndyCar in 2012, with a mandated twin-turbo configuration in 2014. BorgWarner is the exclusive supplier of turbocharger kits, with all cars using the EFR7163 model since 2014 to save costs. IndyCar Series cars don't use an intercooler kit to avoid additional weight; ethanol fuel burns at lower temperatures, which helps keep the engine cool.
Transmission and clutch
Since 2008, IndyCar Series cars have used an electronically actuated 6-speed semi-automatic sequential gearbox with a paddle-shift system supplied by Xtrac Limited. From 1996 to 2007, they used a hand-shifted 6-speed sequential manual transmission, also supplied by Xtrac from 2000 to 2007. The clutches are carbon with steel housing, operated by foot-pedal from 1996–2011 and hand-paddle steering wheel from 2012–present, provided by AP Racing. Mechanical limited-slip differentials are permitted, and all IndyCar Series car drivetrains are rear mid-engine with rear-wheel drive.
Fuel
Initially, the Indy Racing League (IRL) used methanol for safety reasons, which made it visible with a blue haze during night races. To enhance visibility during the day, additives were included to give the flames color.
In 2005, Paul Dana's sponsorship from the Ethanol Promotion and Information Council (EPIC) aimed to correct misconceptions about ethanol's impact on engine performance in road cars. Although Dana died in 2006, the IRL had already started switching to ethanol, using a 90%/10% methanol-ethanol mix in 2006. By 2007, they advertised "100% Fuel Grade Ethanol" (actually 98% ethanol and 2% gasoline) to promote renewable fuel use. A full E100 mixture was used at the 2010 São Paulo Indy 300 in Brazil.
To offset the power loss from ethanol, engine displacement increased, and fuel tank capacity decreased due to better mileage. Ethanol is less harmful upon human contact and less polluting than methanol, with fumes often compared to apple cider.
Sunoco became the official fuel supplier in mid-2010, and in 2012, the ethanol blend was reduced to 85%. Speedway LLC took over in 2019, maintaining the E85 formula until 2022. In 2023, Shell USA began supplying 100% ethanol-sourced fuel.
Fuel cell
Currently, IndyCar Series cars use rubber fuel cells wrapped in Kevlar for impact protection. Since 2012, these cells hold 18.5 US gallons (70 litres), reduced from 22 gallons (83 litres) in 2007–2011, 30 gallons (114 litres) in 2004–2006, and 35 gallons (132 litres) in 1997–2003.
Brakes
From 1996 to 2011, IndyCar Series cars used slimmer carbon brake rotors with 4-pot calipers and carbon pads on all-oval races. In 2005, thicker steel brake rotors with 6-pot calipers and carbon pads were introduced for road and street course races. Since 2012, carbon brake rotors have been used on all tracks. PFC has supplied brake packages since 2017, while Brembo supplied them in 2012–2016 and Alcon in 2003–2011.
Wheels
Since 1996, BBS and O.Z. Racing has supplied forged aluminum alloy wheels for all IndyCar Series cars. The wheel sizes have been 10 in × 15 in (front) and 14 in × 15 in (rear) since 1996 and were used until at least the 2022 season. 18-inch wheels may be adopted if the Dallara DW12's successor is released for the 2023 season onward.
Tyres
Firestone has been the sole tire supplier for the IndyCar Series since 2000, after Goodyear supplied tires from 1996 to 1999. The series has used bespoke tire compounds since 1996, re-profiled in 2003. Front tire sizes are 305/45-R15, and rear tire sizes are 415/40-R15. Road/street events have primary and alternative dry tires and full-rain tires, while oval races use a single specification with a slight stagger in the rear tires to aid cornering.
Engines: First Generation 1996
In the initial 1996 IRL season and the first races of 1996–97, engines from the CART series were used, following the 1995 Indianapolis 500 rules. V-8 engines had a 45 inHg boost, while the Menard-Buick V6 engine had a 55 inHg boost at all races, unlike in the CART era. Ford-Cosworth supported teams using older engines, causing tension with CART. The Ilmor Mercedes V-8 engine was permitted but only used once at the 1996 Indy 500.
Engines: Second Generation 1997-2011
From 1997, IRL cars used 4.0-litre V8 methanol engines from General Motors (Oldsmobile) and Nissan (Infiniti), capped at 10,000 rpm and 280 lb, producing 600–700 hp. In 2000, displacement decreased to 3.5 litres, and the production-based requirement was dropped. Infiniti's engines were initially weaker, but improved by 2000. Oldsmobile was rebadged as Chevrolet in 2002, but faced competition from Toyota and Honda, which led to Chevrolet ending its program in 2005. Toyota also withdrew after 2005, leaving Honda as the sole engine supplier from 2006 to 2011. Honda focused on durability and cost reduction, with engines lasting 1,200 miles between rebuilds and producing around 650 hp, with a push-to-pass system increasing it to 690 hp.
Engines: Third Generation 2012-present
The third-generation IndyCar formula, introduced in 2012, brought back engine manufacturer competition. The fuel-efficient DOHC 2.2-liter twin-turbo V6 engines, supplied by Chevrolet and Honda, produce 550–750 hp. McLaren supplies the engine control unit. An electric push-to-pass overtake system, producing roughly 60 hp, was reintroduced in 2012. From the 2024 season, hybrid systems will be introduced.
Suspension
IndyCar Series cars all feature a multilink suspension system with double A-arms, pushrods, a third spring, and an anti-roll bar.
Spark plugs
Since 2012, Bosch (Chevrolet) and NGK (Honda) have been the spark plug providers for all IndyCar Series cars. NGK was the sole supplier from 2006–2011 when Honda was the standard engine supplier. Before that, Denso supplied spark plugs for Toyota-powered cars from 2003–2005.
Cockpit and safety features
IndyCar Series cars use carbon-fiber shell seats with 6-point safety restraints, and Cosworth steering wheels with buttons for in-race adjustments. Pi Research Sigma Wheels were used for data display until 2017, replaced by Cosworth's Configurable Display Unit 4.3. Cockpits are open but protected by Zylon, foot protection, and padding. Since 2020, a cockpit protection system, including a Halo and "aeroscreen" provided by Red Bull Advanced Technologies, has been implemented to reduce head injuries from debris.
Other features
IndyCar cars have carbon-fiber seats, Cosworth steering wheels, and cockpit protection including Zylon, padding, and, since 2020, a Halo/aeroscreen system to prevent head injuries.
IndyCar points system
1st: 50 points
2nd: 40 points
3rd: 35 points
4th-10th: 32-20 points (decrease by 2 points)
11th- 24th:19-6 points (decrease by 1 point)
25th-33rd: 5 points
IndyCar 2025 Championship Standings
Drivers:
1st - Alex Palou 626 points (this season’s champion)
2nd - Pato O’Ward 475 points
3rd - Scott Dixon 411 points
4th - Christian Lundgaard 398 points
5th - Kyle Kirkwood 387 points
6th - Will Power 342 points
7th - Felix Rosenqvist 337 points
8th - Colton Herta 333 points
9th - Marcus Armstrong 331 points
10th - David Malukas 287 points
11th - Scott McLaughlin 285 points
12th - Rinus Veekay 272 points
13th - Christian Rasmussen 257 points
14th - Santino Ferrucci 253 points
15th - Graham Rahal 246 points
16th - Alexander Rossi 244 points
17th - Kyffin Simpson 240 points
18th - Josef Newgarden 239 points
19th - Conor Daly 220 points
20th - Marcus Ericsson 208 points
21st - Nolan Siegel 195 points
22nd - Callum Illot 191 points
23rd - Louis Foster 189 points
24th - Robert Shwartzman 183 points
25th - Sting Ray Robb 160 points
26th - Devlin Defrancesco 145 points
27th - Jacob Abel 107 points
28th - Takuma Sato 36 points
29th - Helio Castroneves 20 points
30th - Ed Carpenter 16 points
31st - Jack Harvey 12 points
32nd - Ryan Hunter-Reay 10 points
33rd - Kyle Larson 6 points
34th - Marco Andretti 5 points
Manufacturers:
1st - Honda: 12 wins, 10 poles, 1389 points
2nd - Chevrolet: 3 wins, 7 poles, 1177 points
Summary
Now you’ve learnt the history, the engineering, the regulations and their changes, and the 2025 season standings: will you watch the final two races of the season?
This weekend, they are competing in Milwaukee, with the race starting at 7 pm BST on the 24th of August. The season finale on the 31st of August is being held in Tennessee, with that race also starting at 7 pm BST.
Article written by Alice Seager ©️ Alice Seager 2025
