The Car of Tomorrow was not a Failure

Many NASCAR fans see the NextGen racecar as wiping away the last vestiges of the much-reviled Car of Tomorrow. But the CoT was far from a failure. You can bet your life — or your favorite drivers’s life — on that.

B. C.(oT)

In the early 2000’s, NASCAR was facing the same Big Three problems that face all of motorsports.

The Big Three problems any motorsport faces: balancing safety, cost and competition

While they still face these challenges today, the situation was much more dire back then.

  • They’d lost four drivers (Adam Petty, Kenny Irwin, Jr., Tony Roper and Dale Earnhardt) within a space of a year.
  • A number of marquee drivers had retired
  • They had a new broadcasting partner
  • The series changed from lots of one- and two-car teams to fewer teams, each with four (or more) cars.
  • Rules (e.g. a common roof line, a penalty for changing engines) were implements to keep teams from spending themselves out of existence.
  • The series lost their sponsor of 33 years.
  • Teams spent thousands of dollars in aerodynamics wars. They made make tiny tweaks to a car body to get a tiny edge.

Remember the Twisted Sister? The car that prompted some to say it looked like it had been in an accident before it’d even gotten on the track?

The 'twisted sister' NASCAR racecar looked like it had already been in an accident before it even got out on track.

The Car of Tomorrow, Yesterday

NASCAR wanted the Car of Tomorrow to satisfy all three issues: cost, safety and competition. Like most experiments, some results were better than expected, some were as expected and some were disappointing.

NASCAR fans’ dislike of change is legendary. When the CoT arrived on March 25th, 2007, people were predisposed to dislike it.

The Car of Tomorrow featured a wing and a splitter instead of a spoiler and an airdam

The most visible changes were a wing instead of a spoiler and a splitter instead of an air dam. The body shape was standardized, with minor modifications in the noses. The only way a casual fan could tell which manufacturer’s car was which was to read the decal.

Kyle Busch won the first CoT race, but he wasn’t big on it, either.

I’m still not a big fan of these things. I can’t stand to drive them, they suck.”

Kyle Busch, after winning the first COT race.

Aerodynamics and Handling

The CoT was designed to help drivers maneuver better in traffic and to enable cars to pass each other — a problem NASCAR is still dealing with in the NextGen car).

The Body

With limited skew allowed in the body, the CoT looked more like a production car than the twisted sister did; however, it didn’t look like one of the sexier, sportier cars that has always been the model for racing. Manufacturers, unhappy with the lack of differentiation between makes, convinced NASCAR to specialize the Gen 6 car.

Tony Stewart called it ‘The Flying Brick’ because it was big and boxy.

Ideally, a team wouldn’t need different cars for different tracks. However, teams quickly found areas they could exploit for different tracks, so they didn’t end up making many fewer cars.

The CoT was the first move toward having all teams adhere to a universal standard. The grey area decreased, but all teams understood the expectations.

The Center of Gravity

The CoT’s center of gravity was much higher. That means more load transfer, poorer handling and more force on the right-side tires.

The Wing

There were concerns about the wing giving cars the propensity to go airborne at high speeds and high yaw angles. After trying different side-plate sizes and positions, NASCAR went back to a spoiler.

The Splitter

The splitter is a versatile, easily adjustable aerodynamic piece that provides front downforce. This piece enables NASCAR to do things like quickly develop a new short-track package.

The initial design had braces that required a pit crew member to stick their hand between when cleaning the grille. A badly-timed pit exit could rip off someone’s hand. I was glad when they changed the design.


When NASCAR decided to use a splitter for the Car of Tomorrow, they had to decide what to make it out of. They needed something strong, durable, not super-expensive, and that wouldn’t make a mess on track in an accident.

They started with wood (not strong enough), looked at carbon fiber (too splintery and way too expensive), and ended up testing hundreds of materials.

The winner was Tegris, a lightweight, stiff, durable polymer composite from Milliken & Company. They weave a polymer fiber into sheets (like carbon fiber) and then heat it under pressure to form a composite. The photo on the left, below, shows the material before and after consolidation. The finished composite has a woven pattern because it starts out as fabric.

You can buy Tegris with plain, twill or herringbone weaves now. It’s paintable, and you can get it in four colors: silver, coyote, tan and natural.

Tegris is a stiff, lightweight, durable material that is used for NASCAR splitters

Tegris is almost as strong as carbon fiber, but at a significantly reduced price. The splitter has evolved over the years, but it is still made of Tegris.


It’s sometimes hard to appreciate how innovative and successful the CoT was. Much like with social distancing, when something works perfectly, nothing happens. That there have been no deaths in NASCAR’s top three series since 2001 is a direct result of the CoT. It’s also a testament to the ingenuity and dedication of the people in the NASCAR R&D Center.

The Chassis

The CoT marked the first time NASCAR sent an AutoCad file to every team and said ‘this is how you will build your chassis’. The design incorporated everything NASCAR had learned about safety from how welds should be made to where the driver sits.

The Car of Tomorrow's chassis

Some of the under-appreciated elements of the CoT:

  • The driver’s seat moved away from the door, toward the center of the car.
  • The drive shaft (a long, heavy piece of metal) was enclosed in a protective sleeve. This keeps it from becoming a projectile in an accident
  • The greenhouse (the top area of the cockpit) became larger. The drivers had more room and easier egress in case of emergency.
  • A reinforced greenhouse protected the driver in case of a rollover.
  • Five bars on the driver’s side door provided extra protection against T-bone hits.

NASCAR’s engineers made some modifications in response to specific accidents, like Kyle Busch breaking his leg at Daytona and Brad Keselowski fracturing his ankle during testing at Watkins Glen. But the CoT chassis remains remarkably robust, which is why it is the basis of the Gen-6 and the NextGen racecar.

Impaxx Foam

The CoT added even more protection against driver-door impacts by adding a foam made by Dow called IMPAXX. That’s the blue stuff you see when a crash peels sheet metal off the door.

IMPAXX is a safety foam that is used in NASCAR, as well as increasingly in passenger cars

While IMPAXX is a foam, it’s not squishy like, say, a foam pillow. It’s rigid, like Styrofoam, but it’s much stronger, while remaining lightweight. Styrofoam has to stand up to your USPS, UPS and FedEx delivery people. IMPAXX has to stand up to a 190-mph race car.

Impaxx squishes when impacted. That squishing (which is really just the breaking of atomic-bonds) requires energy — lots of energy. The basis of safety is that energy dissipated in the car doesn’t reach the driver.

A picture showing how much different types of foam crush under impact: The more crushing, the more energy absorbed

IMPAXX comes in different densities for different applications. It’s now also used as roll-bar padding. In passenger vehicles, it’s found in the headliner and also protects against side and lower-leg impacts. It’s easy to shape and can be fabricated in panels that, like the door application, fit right into place on the chassis.

Tegris (Again)

The word ‘Tegris’ comes from the Latin ‘You are Protected’. While Tegris came into NASCAR as the ideal splitter material, this material has many uses. Milliken promotes Tegris for any application requiring impact resistance, stiffness and light weight, which includes bullet-resistant materials, kayaks and suitcases.

NASCAR put a slab of Tegris in the driver’s side door to prevent cockpit intrusions. So in addition to giving the driver front downforce, this super material also gives him peace of mind.

A Completely Successful Experiment is a Bad Experiment

People like to compare anything new to ‘putting a man on the moon’, but there’s a difference: We knew how to put men on the moon. The steps were hard, but we knew what they were.

No motorsports sanctioning body has solved the passing problem or achieved the perfect balance of safety, competition and cost. The CoT was a bold step forward. Not everything worked, but you can’t make incremental changes when you only design a new car every five or ten years.

Part of drivers’ hostility toward the car may have reflected how NASCAR operated, rather than the car itself. NASCAR is now more of a partner with teams, rather than a dictatorial body that demands everyone toe the line (or be fined).

Very few things in the world are all good or all bad. I’m not sure why people feel they must take sides: You love something (or someone) or you absolutely despise it. That’s not realistic, nor is it healthy.

It’ll be the same when we finally see the NextGen car on track. It would be great if it was perfect, but it probably won’t be. Some elements will work better than expected, and some elements will disappoint.

But it will be a step ahead, and that’s all you can ask.

I don’t care how ugly someone might say a race car is. They all look pretty standing in Victory Lane.

David Reutimann, via Ryan McGee

2 Trackbacks / Pingbacks

  1. Is Stockcar Racing the Safest Form of Motorsports? : Building Speed
  2. The NextGen Chassis : Building Speed

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