Dr. Diandra: Next Gen tech vs. Martinsville


Martinsville Speedway is the platonic ideal of short-track racing.

We expect — we look forward to — banging, bumping and short tempers. Add in high-profile drivers yet to win a race and the result is likely to be accidents and spins.

Will the Next Gen car’s composites, brakes and suspension stand up to the task?

Last year’s two Martinsville races tied for the most cautions (15). The spring Martinsville race featured seven spins and five accidents, while the fall race had only one spin, but 11 accidents. The track’s closest competitors (Nashville, fall Darlington and fall Texas) each had 11 cautions.

Thirty-one cars spun or were involved in accidents at 2021 Martinsville races.

Cautions by race and type for the 2021 NASCAR Cup Series

Saturday night’s race will be 400 laps instead of the traditional 500. We’ll have to scale down our expectations — and the numbers of cautions, but we still have three stages. Last spring, nine of the 13 spins/accidents came in the third stage.

Next Gen car at Martinsville

Two Next Gen design changes could enhance the propensity for bumping and banging: Brakes and body.

Enlarging the wheels from 15 inches to 18 inches means more room for brakes. A driver can brake later going into a corner and thus go deeper into the corner. With more ability to dissipate heat, wearing out the brakes won’t be as much of a problem as in past Martinsville races.

“We have more braking power than we have grip,” Alex Bowman said.

“Before,” Dale Jarrett said on the NASCAR on NBC podcast, “if you took it in a little too deep, not only did you drive it further into the corner, you started wheel hopping.”

Driving the car further into the corner increases the the potential for contact.

“Not that I’m looking for wrecks,” Jarrett said. “Contact is what we look for and that’s why we love those short tracks.”

The second change – composite car bodies – first appeared in 2017 in the Xfinity Series, where they proved more resilient than steel.

Composite bodies rebound from scrapes with the wall, but their real advantage is standing up to cut tires. A tire coming apart acts like the string in a weed whacker: It can cut right through metal.

That whipsaw action can transform the minor problem of a blown tire into the major problem of a shredded quarter panel.

“The car from a door-banging side of things, rubbing, not cutting tires down, we haven’t really seen that happen yet,” Joey Logano told Dustin Long.

And that’s thanks to composites.

What is a composite?

Composite is short for composition material. Two dissimilar materials combine to make a material with properties better than either material individually.

Remember that Reese’s ad starring Kevin Harvick and IndyCar driver Tony Kanaan? They’re selling a taste composite. Peanut butter cups are good. Caramel is good. When you put them together, it tastes better – and different – than either one separately.

Structural composites, like those in the Next Gen car body, are strong but lightweight. These materials originally developed in the aerospace industry, where every pound increases the fuel bill, or even the ability to get off the ground in the first place.

Composites follow a simple formula. A matrix – a fiber or particle – combines with a binder like an epoxy or a cement.

You are more familiar with composites than you might think. Wood is a composite. Cellulose is a strong, fibrous material. Soft, gluey lignin holds the cellulose fibers together.

Your bones are also composites. Hydroxyapetite — a strong-but-brittle mineral — embeds in collagen, which is soft and cushiony.

Paper mache, concrete, asphalt, adobe, mother of pearl and plywood are all composites. Although composites are new to bodies, NASCAR already uses them in seats, dashboards and even NACA ducts.

Five Star Race Car Bodies in Twin Lakes, Wisconsin makes the Next Gen body. Although the specific materials in the Next Gen body are proprietary, the matrix includes carbon fiber and Kevlar.

The fibers are woven into fabric. Sheets of fabric are stacked, with the fiber direction varied so that the composite is equally strong in all directions.

A drawing showing a fiber for a composite, the fiber woven into cloth and the process of stacking the cloth prior to molding

There’s one more component to the composite body. It takes a lot to break carbon fiber composites, but they can break. Because they are brittle, they fracture and leave shards of material everywhere – about the last thing you want on a racetrack.

So there’s one more element to counteract the brittleness: Layers of a proprietary material sandwich the carbon fiber and help hold it together in case of accidents.

A graphic showing how fiberglass bookends the carbon fiber-Kevlar composite fabric

After loading the fabric layers into a mold, they are saturated with an epoxy-type resin. Suction pulls the fabric tightly against the mold while the composite cures.

Once cured, any holes or tabs necessary for fitting the body onto the chassis and other body pieces are drilled. Even the nuts used in flange fitting the body together are glued into place.

And there’s only one way the parts fit together, so unlike my experiences with flat-pack furniture, it’s pretty much impossible to do it wrong.

Why carbon-fiber composites instead of steel?

Carbon fiber composite is five times stronger than steel by weight. Neither chemicals nor heat damage it.

“The superior flame resistance is one of the things we’re really proud of achieving,” said Corey Schultz, vice president of sales and marketing at Five Star Race Car Bodies.

It’s also twice as stiff as steel, which means that carbon-fiber composite parts don’t deflect when a car is going 200 mph. NASCAR had to add rules for the Gen-6 car to prevent teams from making hoods and decklids that changed shape at speed and provided an aerodynamic advantage.

Another feature of the Next Gen composite is that it is repairable – but not by teams. Pieces in need of attention must be returned to Five Star for repairs.

So more bumping and banging at Martinsville?

Given bigger brakes and stronger bodies, you might expect drivers to turn the aggression knob all the way up to eleven at Martinsville.

But maybe not.

Suspension issues arose at the Clash at the L.A. Coliseum, which is the track most similar to Martinsville that’s hosted the Next Gen car. Those failures may have been due to the lack of run-off space, or just unfamiliarity with the new car. But drivers took note.

“Before, we didn’t want to hit the wall because of aero,” Chase Elliott said at Richmond last week. “Now, it’s the suspension.”

In particular, the rear toe link appears to be the weakest part of the Next Gen suspension. Toe is the angle the wheels make with the car’s centerline.A graphic explaining toe as it refers to wheelsThe toe link is the part that moves one side of the wheel in or out. It’s really nothing more than a rod with connectors at either end.

“It’s crazy,” Logano said. “You look at these cars that get out of the race because something broke on their car after a wreck and the body looks fine. … Even Daytona, we saw cars crash really hard and it’s kind of like the body pops back and it doesn’t look bad, but everything behind it is crushed.”

NASCAR implements safety changes after Talladega crash


NASCAR is implementing changes to Cup cars that strengthen the right side door area and soften the frontal area after reviewing the crash between Kyle Larson and Ryan Preece at Talladega Superspeedway in April.

The changes are to be in place for the July 9 race weekend at Atlanta Motor Speedway.

Larson and Preece were uninjured in the vicious crash late in the race at Talladega. Larson’s car was turned and slid down the track to the apron before coming back up in traffic. Preece’s car slammed into the right side door area of Larson’s car.

Dr. John Patalak, NASCAR vice president of safety engineering, said the difference in velocity of the two cars at the time of impact was 59 mph.

“It’s pretty hard to find that on the racetrack normally,” Patalak told reporters Thursday during a briefing.

The severe impact moved a right side door bar on Larson’s car. NASCAR announced last month that it was allowing teams to add six right side door bar gussets to prevent the door bars from buckling in such an impact.

Thursday, NASCAR announced additional changes to the cars. The changes come after computer simulations and crash testing.

NASCAR is mandating:

  • Steel plate welded to the right side door bars
  • Front clips will be softened
  • Front bumper strut softening
  • Front ballast softening
  • Modified cross brace

Patalak said that NASCAR had been working on changes to the car since last year and did crash testing in January at the Transportation Research Center in East Liberty, Ohio. NASCAR did more work after that crash test.

As for the changes to the front of the car, Patalak said: “From an engineering standpoint we’re reducing the buckling strength of those individual parts and pieces. The simplified version is we are increasing the amount of crush that the front clip will be capable of. That’s all an effort to reduce the accelerations that the center section and driver will be exposed to during these frontal crashes.”

Adding the steel plate to the door bars is meant to strengthen that area to prevent any type of intrusion or buckling of the door bars in a similar type of crash.

Patalak also said that NASCAR inspected the car of Blaine Perkins that barrel rolled during the Xfinity race at Talladega in April. Patalak said that NASCAR consulted with Dr. James Raddin, Jr., who was one of the four authors of the Earnhardt investigation report in 2001 for the sanctioning body, in that incident.

Dr. Diandra: Brad Keselowski driving RFK Racing revival


Brad Keselowski surprised many when he didn’t re-sign with Team Penske in 2021. Penske was his home since 2010, and the team who helped him to a Cup Series championship in 2012. But Jack Roush offered Keselowski something Roger Penske couldn’t — ownership stake in the team.

Keselowski knew an RFK Racing revival would be an challenge, but also that he was prepared for it.

“I’ve been studying my whole life for this moment, and I’m ready for the test,” Keselowski said during the announcement of the new partnership.

A historic team with historic ups and downs

Roush Racing entered Cup competition in 1988. It didn’t win that first year, but the company collected at least one checkered flag every year from 1989-2014 — except for 1996.

Roush was one of the first owners (along with Rick Hendrick) to appreciate the advantages of multi-car teams. By 2003, Roush Racing fielded five full-time teams. In 2005, all five Roush cars made the playoffs, accumulating 15 wins between them. Their dominance prompted NASCAR to limit teams to four cars. That limit remains today.

Roush sold half the team to Fenway Sports Group in 2007. The renamed Roush Fenway Racing team, however, never reached the highs of 2005 as the graph below shows.

A vertical bar chart showing the challenges Brad Keselowski has in driving RFK's revival

The 2015 season was Jack Roush’s first winless season since 1996. By the time Ricky Stenhouse Jr. won two races in 2017, RFR was down to two cars. The company had four consecutive winless seasons before Keselowski came on board.

Keselowski is a perfect choice to drive the RFK revival. After all, how many other NASCAR drivers run a 3D-printing business? Or worry about having enough properly educated workers for 21st century manufacturing jobs?

“I feel like I’m buying into a stock that is about to go up,” Keselowski said.

Keselowski’s record

The new RFK Racing team started off strong at Daytona, with Keselowski and teammate Chris Buescher each winning their Duels. During that week, NASCAR confiscated wheels from both drivers’ cars. Despite concerns about the team’s modifications, NASCAR ultimately levied no penalty. But after the fifth race of the year at Atlanta, NASCAR docked Keselowski 100 points for modifying single-source parts. Keselowski needed to win to make the playoffs.

It wasn’t Keselowski, but Buescher who won the first race under the new name. Unfortunately, Buescher’s Bristol win came too late to make the playoffs.

Keselowski finished 2022 ranked 24th, the worst finish since his first full-time season in 2010 when he finished 25th.

In the table below, I compare Keselowski’s finishes for his last two years at Team Penske to his finishes with RFK Racing in 2022 and the first 15 races of 2023.

Comparing Brad Keselowski's finishes for his last two years with Penske and his first two years (so far) with RFK RacingKeselowski’s lack of wins since switching teams is the most obvious difference; however, the falloff in top-five and top-10 finishes is even more significant. Keselowski was not only not winning races, he often wasn’t even in contention. In 2020, Keselowski finished 91.7% of all races on the lead lap. In his first year with RFK, that metric dropped to 61.1%.

On the positive side, his numbers this year look far better than his 2022 statistics. Keselowski finishes on the lead lap 86.7% of the time and already has as many top-10 finishes in 15 races as he had in all 36 races last year.

Keselowski’s top-five finish rate improved from 2.8% in 2022 to 20.0% this year. That’s still off his 2021 top-five-finish rate of 36.1%, but it’s a step forward.

I summarize the last four years of some of Keselowski’s loop data metrics in the table below.

A table comparing Brad Keselowski's attempt to drive RKF's revival with his last two years of loop data at Penske

In 2022, Keselowski was down between six to seven-and-a-half points in starting, finishing and average running positions relative to 2021. This year, he’s improved so that the difference is only in the 2.6 to 3.6-position range.

Two keys for continued improvement

Ford is playing catch-up this year, having won only two of 15 points-paying races. Ryan Blaney, who won one of those two races, has the highest average finishing position (11.3) among drivers with at least eight starts. Keselowski is 14th overall with a 15.7 average finishing position, and fourth best among Ford drivers. Buescher is finishing an average of 1.2 positions better than his teammate.

Kevin Harvick is the top-ranked Ford driver in average running position, coming in sixth overall. Keselowski is 13th overall in average running position and the fourth-best among the Ford drivers.

Average green-flag speed rank is the average of a driver’s rank in green-flag speed over all the races for which he was ranked. Harvick is the fastest Ford as measured by this metric, ranking eighth among all drivers who have completed at least eight races. Keselowski is the fifth-fastest Ford, but the 20th-ranked driver in average green-flag speed rank.

The other issue, however, is particular to Keselowski: He is involved in a lot of accidents. That’s not new with Keselowski’s move to RFK Racing. Since 2016, Keselowski has been involved in at least eight caution-causing incidents every year.

What may be new is that he has a harder time recovering from non-race-ending incidents now than he did at Penske.

In 2021, Keselowski was involved in 12 caution-causing accidents. Last year, it was 10 (nine accidents and a spin). He’s already been involved in 12 incidents this year, the most of any full-time driver.

Keselowski isn’t too concerned about accidents. He views them as a consequence of pushing a car to its limits. His competitors, however, have called him out for for his aggressive driving style.

Neither accidents nor Keselowski’s attitude toward them changed with his transition from Team Penske to RFK Racing.

Except now he’s the one paying for those wrecked cars.

NASCAR weekend schedule at Sonoma Raceway


The NASCAR Cup and Xfinity Series head to Sonoma Raceway this weekend. This marks the first time the Xfinity Series has competed at the 1.99-mile road course.

The Cup and Xfinity Series will take the following weekend off before the season resumes at Nashville Superspeedway. NBC and USA will broadcast each series the rest of the year, beginning at Nashville.

Sonoma Raceway

Weekend weather

Friday: Mostly cloudy with a high of 69 degrees.

Saturday: Mostly cloudy with a high of 73 degrees. Forecast is for a high of 70 degrees and no chance of rain at the start of the Xfinity race.

Sunday: Mostly cloudy with a high of 67 degrees and a 1% chance of rain at the start of the Cup race.

Friday, June 9

(All times Eastern)

Garage open

  • 11 a.m. — ARCA Menards Series West
  • 1 – 10 p.m. — Xfinity Series

Track activity

  • 2 – 3 p.m. — ARCA West practice
  • 3:10 – 3:30 p.m. — ARCA West qualifying
  • 4:05 – 4:55 p.m. — Xfinity practice (FS1)
  • 6:30 p.m. — ARCA West race (64 laps, 127.36 miles; live on FloRacing, will air on CNBC at 11:30 a.m. ET on June 18)

Saturday, June 10

Garage open

  • 12 p.m. – 8 p.m.  — Cup Series
  • 1 p.m. — Xfinity Series

Track activity

  • 3 – 4 p.m. — Xfinity qualifying (FS1)
  • 5 – 6 p.m. — Cup practice  (FS2)
  • 6 – 7 p.m. — Cup qualifying  (FS2)
  • 8 p.m. — Xfinity race (79 laps, 156.95 miles; FS1, Performance Racing Network, SiriusXM NASCAR Radio)

Sunday, June 11

Garage open

  • 12:30 p.m. — Cup Series

Track activity

  • 3:30 p.m. — Cup race (110 laps, 218.9 miles; Fox, PRN, SiriusXM NASCAR Radio)


NASCAR penalizes Erik Jones, Legacy MC for L1 violation


NASCAR has docked Erik Jones and Legacy Motor Club 60 points and five playoff points each, suspended crew chief Dave Elenz two races and fined him $75,000 for the L1 violation discovered this week at the R&D Center. The team was found to have modified the greenhouse.

The penalty drops Jones from 26th to 30th in the standings heading into Sunday’s race at Sonoma Raceway.

MORE: NASCAR’s $1 million question is can the culture change?

“We have been diligently working with NASCAR regarding the penalty and are working internally to determine the course of action in response,” said Joey Cohen, vice president, race operations for Legacy MC, in a statement. “We will announce that decision within the timeframe determined by the NASCAR Rule Book.”

Cohen will serve as interim crew chief during Elenz’s suspension.

Jones’ car was among those brought to NASCAR’s R&D Center in Concord, North Carolina, after last weekend’s race at WWT Raceway.

NASCAR cited the team for violating:

Section 14.1.C: Vehicles must comply with Section 14 Vehicle and Driver Safety Specifications of the NASCAR Rule Book at all times during an Event. Failure to comply will be subject to Penalty pursuant to Section 10 Violations and Disciplinary Action.

Section 14.1.D: Except in cases explicitly permitted in the NASCAR Rules, installation of additional components, repairs, deletions, and/or modifications to Next Gen Single Source Vendor-supplied parts and/or assemblies will not be permitted.

Section 14.1.2.B: All parts and assemblies must comply with the NASCAR Engineering Change Log.

NASCAR also announced penalties Wednesday in the Craftsman Truck Series.

Crew chief Andrew Abbott has been fined $5,000, Young’s Motorsports has been penalized 25 points and Chris Hacker has been docked 25 points for a violation with the team’s window net.

Crew chief Charles Denike has been fined $2,500 for a lug nut not properly installed on Christian Eckes‘ truck for TRICON Garage.