IndyCar Steering Wheel Explained: Every Button, Paddle and Dial
Welcome to the Happy Hour Racing IndyCar Tech Breakdown, where we take one confusing piece of an Indy car and make it make sense. No engineering degree required.
The Short Version
An IndyCar driver has no power steering, no traction control and no ABS, so nearly everything they can change during a race sits in their hands. The current Cosworth CCW Mk3 wheel carries a five-inch screen, 12 buttons on the face, four more on the back, four rotary dials and two thumbwheels. INDYCAR's rulebook spells out which switches every car must have, and it bans any electronics sitting between the driver's thumb and the car. Here is what each one actually does.
The Wheel Is the Car's Control Panel
Teams are allowed to design their own steering wheel electronics, but rule 14.19.1.2 says they have to build around the approved Cosworth display, and the required switches must report their real position straight through a Cosworth switch board with nothing in between. In practice there are two legal wheels in the paddock: the Cosworth CCW Mk2 and the newer CCW Mk3.
The Mk3 showed up at the 2025 season opener in St. Petersburg. Cosworth grew the rim from 280mm to 300mm across, which matters a lot in a car with no power steering, because a wider rim gives the driver more leverage on the front tires. Inside that rim sits a five-inch configurable screen, 12 front buttons, four rear buttons, four rotary switches and two thumbwheel encoders. RACER reported in December 2024 that eight of IndyCar's 11 full-time teams took the new wheel as an option for 2025.
The NTT IndyCar Series has approved the use of the Cosworth Mk 3 steering wheel for 2025. The optional new model has been chosen by eight of IndyCar's 11 full-time teams and presents drivers with a wider frame to generate more force and leverage.
— RACER (@RACERHQ) December 27, 2024
The Buttons That Actually Change the Race
Rule 14.19.1.2 names the inputs every car has to carry. Here they are in plain English.
- Overtake. The push to pass button. It turns up turbo boost for a short burst, and on road and street courses drivers get a fixed budget for the race, usually between 150 and 200 seconds with a cap on each individual push. Ovals do not get it.
- Pit lane speed limiter. One press hands throttle control to the engine computer so the car cannot break the pit lane speed limit. Speeding penalties still happen, because drivers hit it late.
- Neutral and reverse. Neutral is for pit stops. Reverse exists so a driver can back out of a runoff area or a tire barrier, and it is banned in pit lane during a race.
- Weight jacker. Buttons or a rotary that shift cross weight from one side of the car to the other while it is moving. It is how a driver fights a car that goes loose or tight as fuel burns off.
- Hybrid deploy and regeneration request. One input dumps stored energy in for about 60 extra horsepower, the other harvests it back. Most teams put these on the back of the wheel.
- Shift paddles and clutch paddles. There is no clutch pedal in the car. The driver pulls a hand paddle to launch and to find neutral.
- Engine performance map rotary. The fuel mixture dial. Turn it rich for power, lean to stretch a stint.
- Engine diagnostic rotary. A health check the driver can run from the seat when something feels wrong.
- Hybrid regeneration level rotary. Sets how hard the car claws energy back under braking, which changes how the rear of the car behaves on corner entry.
On top of those, teams add the quality-of-life stuff: a push to talk radio button, a fuel reset, a dash scroll to flip screens, and a drink button that runs a pump from a bottle in the car to a tube in the helmet.
A closer look at an @IndyCar steering wheel with @townsendbell and @hinchtown.
— INDYCAR on FOX (@IndyCarOnFOX) May 15, 2025
What the Driver Sees on the Screen
The screen is not decoration. INDYCAR requires three conditions to be shown clearly and uniquely on the race dash: the black flag, the full course yellow and the local yellow. Those lights are triggered by the series through the EM marshalling system, so a driver knows a corner has gone yellow before the flagstand comes into view. The dash also has to display fuel probe status so officials can check it at any time.
Everything else is the team's choice: lap time, the delta to the driver's own best lap, water and oil temperatures, gearbox temperature, fuel remaining, hybrid state of charge. Drivers use it very differently. Will Power checks the dash on the exit of every corner. Scott Dixon has said it does not make much difference to him. Felix Rosenqvist once had the lap time data taken off his wheel entirely because he was looking at it too much.
The Controls That Are Not on the Wheel
Three small levers live in the cockpit beside the driver's legs, and they are some of the most powerful tools in the car. One adjusts the front anti-roll bar, one adjusts the rear, and a bigger one sets brake bias front to rear. Stiffening a bar takes grip away from that end of the car, so a driver running a loose car can soften the rear bar on a straightaway and change the balance without pitting. Brake bias moves where the stopping power lands as fuel burns off and tires go away. The rulebook allows only the Dallara-supplied bias system, so every car does it the same way.
The Rules That Keep It a Driver's Job
This is the part that separates IndyCar from a lot of modern racing. A single driver input may not activate more than one function, so there is no magic button that fixes three things at once. No electronic data of any type may be sent wirelessly to the car or the driver, so an engineer cannot reach out from the pit box and change a setting. The weight jacker can only be moved by the driver, through direct steering wheel inputs, with no outside logic allowed. Computer logic is banned from the braking system entirely. If the car needs something, the person in the seat has to do it at 200 mph with one hand.
What You Will See on Track
Watch an onboard camera on a long straightaway and you will see the busiest two seconds in racing: a thumb on the overtake button, a hand dropping to a bar lever, a mixture dial getting a click, all while the car is still doing 180 mph. Watch a restart and you will see the hybrid get spent in one burst, drivers trying to steal half a car length before the first braking zone. And watch what happens when a car spins on a road course now. The driver can fire the engine back up with the hybrid system and drive away, which is not permitted on ovals, so an oval spin still means a tow.
The Bottom Line
IndyCar deliberately keeps the smart stuff out of the car and puts it in the driver's hands. The wheel is not a computer that drives for them. It is a control panel for a car that will not help them at all.
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