Cup championship crew chiefs worried about tire allotment in Miami

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A 2015 Cup championship trophy sits in crew chief Adam Stevens’ office so he can see it every day.

“I kind of like to be reminded every time I come to work what we’re racing for and what the hard work we put in day in and day out and night in and night out and through all the grind of the season what it’s all for,’’ Stevens said.

He seeks another championship trophy with his driver, Kyle Busch, among the four racing for a title in Sunday’s season finale in Miami (3 p.m. ET, NBC).

The challenge for Busch and Stevens will be more than Martin Truex Jr., Kevin Harvick and Brad Keselowski for the championship. Stevens and other crew chiefs are concerned about the tire limits this weekend.

Cup teams will be allowed nine sets for the race plus the set they use in qualifying. Last year, teams had 12 sets available plus they could also use a set from practice.

Fewer sets of tires could mean more difficult decisions for crew chiefs, especially if there are a number of cautions.

“I think it changes a lot,’’ said Rodney Childers, crew chief for Kevin Harvick.

Kevin Harvick and crew chief Rodney Childers (Photo by Jonathan Moore/Getty Images)

Childers noted that in 2014 when he and Harvick won the title, they used 11 sets of tires in the 400-mile race.

“I don’t feel like there’s enough tires,’’ Childers said of the allotment for Sunday’s race. “The last thing you want to do is run out of tires with 40 laps to go and not be able to do anything or race for a championship at the end. I’ve been trying to push a little bit, see if we can’t get an extra set for the race.’’

Teams were allowed fewer tires in half of the playoff races this season compared to last year. NASCAR cut allotments for some races after examining tire usage by teams with Goodyear. NASCAR sought to have the number of sets available closer to what had been used in previous races.

The concern among crew chiefs is that tires could be critical because how much they wear at Homestead-Miami  Speedway. Greg Stucker, Goodyear director of racing, notes that the track has become one of the highest wear tracks on the circuit.

That’s just one of many concerns crew chiefs have entering the weekend. Paul Wolfe, crew chief for Brad Keselowski, has additional worries. His team has struggled to find speed in the playoffs. Keselowski has finished ahead of Truex twice in the first nine playoff races but neither were at 1.5-mile speedways, the length of Homestead-Miami Speedway.

Keselowski has been slower than Truex and Harvick in green flag speed and on restarts in all four of the playoff races on 1.5-mile tracks this season.

“We’ve just got to go down there and make speed,’’ Wolfe said. “That’s kind of as simple as it is. I feel good about what we’re bringing down there. I don’t know if it’ll be enough, but I’m proud of the effort that we’ve put in.’’

Truex and crew chief Cole Pearn arrive as what some will view as the favorite with seven victories this season, including six on 1.5-mile speedways. Pearn is fine with that role. It’s much better than in 2015, when the team entered the season finale as an underdog.

“I think at that point we were just thrilled to have made it, and I think we didn’t really know what to do,’’ he said. “It was like a dog chasing the car, we finally caught the car and we didn’t know what to do with it. 

“This past year and the year before we really tried to take more time and get ourselves prepared for Homestead itself. So I think, obviously, we won’t see that until this weekend, but it’s been in our mind for a long time, and really trying to get ourselves prepared for this race and probably have put more emphasis on it than we would have if we hadn’t have gone through what we did in 2015.’’

Drivers for Drive for Diversity combine revealed

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The 13 drivers who will participate in the Advance Auto Part Drive for Diversity Combine were revealed Thursday and range in age from 13-19.

The NASCAR Drive for Diversity Development Program was created in 2004 to develop and train ethnically diverse and female drivers both on and off the track. Cup drivers Bubba Wallace, Daniel Suarez and Kyle Larson came through the program.

The 2020 and 2021 combines were canceled due to the impact of COVID-19.

“We are thrilled that we are in a position to return to an in-person evaluation for this year’s Advance Auto Parts Drive for Diversity Combine,” Rev Racing CEO Max Seigel said in a statement. “We are energized by the high-level of participating athletes and look forward to building the best driver class for 2023. As an organization, we have never been more positioned for success and future growth.”

The youngest drivers are Quinn Davis and Nathan Lyons, who are both 13 years old.

The group includes 17-year-old Andrés Pérez de Lara, who finished seventh in his ARCA Menards Series debut in the Sept. 15 race at Bristol Motor Speedway.

Also among those invited to the combine is 15-year old Katie Hettinger, who will make her ARCA Menards Series West debut Oct.. 14 at the Las Vegas Bullring. She’s also scheduled to compete in the ARCA West season finale Nov. 4 at Phoenix Raceway.

 

 

Name

Age Hometown
Justin Campbell 17 Griffin, Georgia
Quinn Davis 13 Sparta, Tennessee
Eloy Sebastián

López Falcón

17 Mexico City, Mexico
Katie Hettinger 15 Dryden, MI
Caleb Johnson 15 Denver, CO
Nathan Lyons 13 Concord, NC
Andrés Pérez de Lara 17 Mexico City, Mexico
Jaiden Reyna 16 Cornelius, NC
Jordon Riddick 17 Sellersburg, IN
Paige Rogers 19 New Haven, IN
Lavar Scott 19 Carney’s Point, NJ
Regina Sirvent 19 Mexico City, Mexico
Lucas Vera 15 Charlotte, NC

 

Dr. Diandra: Crashes: Causes and complications

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Two drivers have missed races this year after hard rear-end crashes. Kurt Busch has been out since an incident in qualifying at Pocono in July. Alex Bowman backed hard into a wall at Texas and will miss Sunday’s race at the Charlotte Roval (2 p.m. ET, NBC).

Other drivers have noted that the hits they’ve taken in the Next Gen car are among the hardest they’ve felt in a Cup car.

“When I crashed it (at Auto Club Speedway in practice), I thought the car was destroyed, and it barely backed the bumper off. It just felt like somebody hit you with a hammer,” Kevin Harvick told NBC Sports.

The three most crucial parameters in determining the severity of a crash are:

  • How much kinetic energy the car carries
  • How long the collision takes
  • The angle at which the car hits

Angle

The last of these factors requires trigonometry to explain properly. You can probably intuit, however, that a shallower hit is preferable to a head-on — or rear-on — hit.

A graphic show shallower (low-angle) hits and deeper (high-angle) hits
Click for a larger view

When the angle between the car and the wall is small, most of the driver’s momentum starts and remains in the direction parallel to the wall. The car experiences a small change in velocity.

The larger the angle, the larger the change in perpendicular speed and the more force experienced. NASCAR has noted that more crashes this season have had greater angles than in the past.

Busch and Bowman both had pretty large-angle hits, so we’ll skip the trig.

Energy — in pounds of TNT

A car’s kinetic energy depends on how much it weighs and how fast it’s going. But the relationship between kinetic energy and speed is not linear: It’s quadratic. That means going twice as fast gives you four times more kinetic energy.

The graph shows the kinetic energies of different kinds of race cars at different speeds. To give you an idea of how much energy we’re talking about, I expressed the kinetic energy in terms of equivalent pounds of TNT.

A vertical bar graph showing kinetic energies for different types of racecars and their energies

  • A Next Gen car going 180 mph has the same kinetic energy as is stored in almost three pounds of TNT.
  • Because IndyCars are about half the weight of NASCAR’s Next Gen car, an IndyCar has about half the kinetic energy of a Next Gen car when both travel at the same speed.
  • At 330 mph, Top Fuel drag racers carry the equivalent of six pounds of TNT in kinetic energy.

All of a car’s kinetic energy must be transformed to other types of energy when the car slows or stops. NASCAR states that more crashes are occurring at higher closing speeds, which means more kinetic energy.

Longer collisions > shorter collisions

That seems counterintuitive, doesn’t it? Who wants to be in a crash any longer than necessary?

But the longer a collision takes, the more time there is to transform kinetic energy.

A pitting car starts slowing down well below it reaches its pit box. The car’s kinetic energy is transformed into heat energy (brakes and rotors warming), light energy (glowing rotors), and even sound energy (tires squealing).

The same amount of kinetic energy must be transformed in a collision — but much faster. In addition to heat, light and sound, energy is transformed via the car spinning and parts deforming or breaking. (This video about Michael McDowell’s 2008 Texas qualifying crash goes into more detail.)

The force a collision produces depends on how long the car takes to stop. Compare the force from your seat belt when you slow down at a stop sign to what you feel if you have to suddenly slam on the brakes.

To give you an idea of how fast collisions can be, the initial wall impact in the crash that killed Dale Earnhardt Sr. lasted only eight-hundredths (0.08) of a second.

SAFER barriers use a car’s kinetic energy to move a heavy steel wall and crush pieces of energy-absorbing foam. That extracts energy from the car, plus the barrier extends the collision time.

The disadvantage is that a car with lower kinetic energy won’t move the barrier. Then it’s just like running into a solid wall.

That’s the same problem the Next Gen car seems to have.

Chassis stiffness: A Goldilocks problem

The Next Gen chassis is a five-piece, bolt-together car skeleton, as shown below.

A graphic showing the five parts of the Next Gen chassis.
Graphic courtesy of NASCAR. Click to enlarge.
The foam surrounding the outside of the rear bumper
The purple is energy-absorbing foam. Graphic courtesy of NASCAR. Click for a larger view.

That graphic doesn’t show another important safety feature: the energy absorbing foam that covers the outside of the bumpers. It’s purple in the next diagram.

All cars are designed so that the strongest part of the car surrounds the occupants. Race cars are no different.

The center section of the Next Gen chassis is made from stout steel tubing and sheet metal. Components become progressively weaker as you move away from the cockpit. The bumper, for example, is made of aluminum alloy rather than steel. The goal is transforming all the kinetic energy before it reaches the driver.

Because the Next Gen car issues are with rear impacts, I’ve expanded and highlighted the last two pieces of the chassis.

The rear clip and bumper, with the fuel cell and struts shaded

The bumper and the rear clip don’t break easily enough. The rear ends of Gen-6 cars were much more damaged than the Next Gen car after similar impacts.

If your initial thought is “Just weaken the struts,” you’ve got good instincts. However, there are two challenges.

I highlighted the first one in red: the fuel cell. About the only thing worse than a hard collision is a hard collision and a fire.

The other challenge is that a chassis is a holistic structure: It’s not like each piece does one thing independent of all the other pieces. Changing one element to help soften rear collisions might make other types of collisions harder.

Chassis are so complex that engineers must use finite-element-analysis computer programs to predict their behavior. These programs are analogous to (and just as complicated as) the computational fluid dynamics programs aerodynamicists use.

Progress takes time

An under-discussed complication was noted by John Patalak, managing director of safety engineering for NASCAR. He told NBC Sports’ Dustin Long in July that he was surprised by the rear-end crash stiffness.

The Next Gen car’s crash data looked similar to that from the Gen-6 car, but the data didn’t match the drivers’ experiences. Before addressing the car, his team had to understand the disparity in the two sets of data.

They performed a real-world crash test on a new configuration Wednesday. These tests are complex and expensive: You don’t do them until you’re pretty confident what you’ve changed will make a significant difference.

But even if the test goes exactly as predicted, they aren’t done.

Safety is a moving target.

And always will be.

NASCAR weekend schedule for Charlotte Motor Speedway Roval

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NASCAR Cup Series drivers race on the road for the final time this season Sunday, as the Charlotte Motor Speedway Roval course ends the playoffs’ Round of 12.

The 17-turn, 2.28-mile course incorporating the CMS oval and infield will determine the eight drivers who will advance to the next round of the playoffs. Chase Elliott won last Sunday at Talladega Superspeedway and is the only driver who has qualified for a spot in the Round of 8.

Entering Sunday’s race, Austin Cindric, William Byron, Christopher Bell and Alex Bowman are below the playoff cutline. Bowman will not qualify for the next round because he is sidelined by concussion-like symptoms.

The race (2 p.m ET) will be broadcast by NBC.

Charlotte Motor Speedway Roval (Cup and Xfinity)

Weekend weather

Friday: Sunny. High of 81 with a 6% chance of rain.

Saturday: Mixed clouds and sun. High of 67 with a 3% chance of rain.

Sunday: Sunny. High of 68 with a 3% chance of rain.

Friday, Oct. 7

(All times Eastern)

Garage open

  • 12 – 5 p.m. — Xfinity Series

Saturday, Oct. 8

Garage open

  • 7 a.m. – 2:30 p.m. — Cup Series
  • 8:30 a.m. — Xfinity Series

Track activity

  • 10 – 10:30 a.m. — Xfinity practice (NBC Sports App)
  • 10:30 – 11:30 a.m. — Xfinity qualifying (NBC Sports App)
  • 12 – 1 p.m. — Cup practice (NBC Sports App, USA Network coverage begins at 12:30 p.m.)
  • 1 – 2 p.m. — Cup qualifying (USA Network, NBC Sports App)
  • 3 p.m. — Xfinity race (67 laps, 155.44 miles; NBC, Peacock, Performance Racing Network, SiriusXM NASCAR Radio)

Sunday, Oct. 9

Garage open

  • 11 a.m. — Cup Series

Track activity

  • 2 p.m. — Cup race (109 laps, 252.88 miles; NBC, Performance Racing Network, SiriusXM NASCAR Radio)

 

Rodney Childers fined $100,000, suspended for four races

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NASCAR has suspended Rodney Childers, Kevin Harvick‘s crew chief, for four races and fined him $100,000 for what the sanctioning body called modification of a part supplied by a vendor.

The team was penalized for a modification to the deck lid.

Harvick, who is out of the Cup Series playoffs, and the Stewart-Haas Racing No. 4 team were docked 100 points.

Harvick’s car and that of Martin Truex Jr. were taken to NASCAR’s Research and Development Center in Concord, N.C. after last Sunday’s race at Talladega Superspeedway. There were no penalties assessed to the Truex team.

Harvick has been particularly critical of the Next Gen car in recent months, once referring to the “crappy-ass parts” provided by suppliers.

Harvick’s car erupted in flames during the Southern 500 Sept. 4 at Darlington Raceway. After he climbed from the smoking car, Harvick blamed the fire on “just crappy parts on the race car like we’ve seen so many times. They haven’t fixed anything. It’s kind of like the safety stuff. We just let it keep going and keep going.

“The car started burning and as it burned the flames started coming through the dash. I ran a couple laps and then as the flame got bigger it started burning stuff up and I think right there you see all the brake fluid that was probably coming out the brakes and part of the brake line, but the fire was coming through the dash.

“What a disaster for no reason. We didn’t touch the wall. We didn’t touch a car, and here we are in the pits with a burned-up car, and we can’t finish the race during the playoffs because of crappy-ass parts.”

MORE: AJ Allmendinger to return to Cup Series in 2023

Unless the team appeals, Childers would miss races at Charlotte, Las Vegas, Homestead and Martinsville and would return for the season finale at Phoenix.

NASCAR president Steve Phelps told the Associated Press that officials have not targeted Harvick. “I would say that’s ridiculous,” he said. “No one has a vendetta against Kevin Harvick or Rodney or anyone at Stewart-Haas Racing.”

On Wednesday afternoon, Harvick tweeted, “Seems strange…” A Childers tweet called the penalty “Shocker…..”.

NASCAR also announced Wednesday it has suspended Young’s Motorsports crew chief Andrew Abbott indefinitely for a behavioral violation during pre-race inspection. He must undergo anger-management training to be reinstated. The team races in the Camping World Truck Series.