Dr. Diandra: Turning at Talladega: 100 mph on ice


The secret — and the challenge — of winning NASCAR races is in the turns. While we normally focus on drafting and pack racing when NASCAR visits Talladega Superspeedway, Talladega was built for turning fast.

Even if you covered the turns in ice, a car could still take them at about 100 miles per hour.

To understand how that’s possible, we have to first understand how cars turn under normal circumstances.

How race cars turn

Talladega is just plain huge. The infield is 247 acres. That’s big enough to fit the Disneyland theme park (160 acres, which includes only the theme park and not the whole resort) and still have enough room left over to almost get the Mall of America in there too — which, come to think of it, is not a bad way to describe the tamer parts of the Talladega infield.

Large tracks like Talladega give drivers more time to build up speed down long straightaways. Wide, sweeping turns don’t force cars to slow down as much as tracks like Bristol or Martinsville.

At Bristol, about 60% of each lap is turning. At Talladega, it’s more like 10-15%. But even at only 10% of the race, drivers can’t win Talladega unless they can master its corners. The turns are where speed is gained or lost. How a car exits a corner determines its ultimate straightaway speed, and how the car enters a turn plays a large part in how it exits.

The force that makes a car turn is called the centripetal force. Even if you’re not familiar with the word, you already know all about centripetal force. You experience it every time you use a cloverleaf highway interchange or ride a merry-go-round or a loop-the-loop roller coaster.

The word ‘centripetal’ means center-seeking. Since cars turn left and right, you may wonder how the turning force always points toward the center of the turn.

Let’s do a thought experiment. Imagine tying a ball to a string. Now whirl it over your head in a horizontal circle.

The string forces the ball to travel in a circle. At every point on the path, the force on the ball points toward the center of the circle, as I’ve shown below.

A graphic showing a ball whirling around in a horizontal circle on a string, and the forces keeping it in a circle
The ball moves in a circle because the string forces it to do so via centripetal force. Centripetal comes from Greek and means ‘center-seeking’. The centripetal force always points toward the center of a turn.

The exact same physics apply to a race car — except the numbers are bigger.

The minimum weight of a Cup Series car (with driver) is about 3,675 pounds. Let’s turn the car in a circle with a radius of 1,100 feet, which is about the turn radius at Talladega. A driver taking the turn at 190 miles per hour requires a little more than 8,000 pounds of force.

That’s four tons.

If the force is any less than that, the car breaks traction and hits the wall. Then we’re talking about some very different physics.

Of course, race cars don’t have strings. Those four modest-sized patches of tire rubber in contact with the track must create those four tons of turning force.

A graphic showing how a race car turns and the directions of the forces making it turn.

In the video below (from the FS1 broadcast of the Martinsville Cup race earlier this month), I’ve shown how the centripetal force points toward the red-and-white curbing throughout the turn. You can also see how exiting the turn prepares the driver to take the best line down the straightaway.

But tracks like Talladega give the tires a little more help turning the car.

Taking it to the bank(ing)

Martinsville is a half-mile track with only 12 degrees of banking. Pole speeds tend to be in the mid-90 mph range. Compare that with Bristol, a similarly small track, but with pole speeds around 130 miles per hour. Banking makes all the difference.

In addition to being the longest track, Talladega has the highest banking of any track NASCAR runs this year: 33 degrees. For reference, most modern staircases have angles between 30 and 35 degrees.

Below, I’ve drawn the banking of a couple NASCAR tracks to scale.

Comparing the baking at Martinsville, Auto Club of California Speedway and Talladega

That banking is magic. To understand why, let’s look first at how a car turns on a flat track.

In the diagram below, the car is turning left and you’re looking at it from behind. The centripetal (a.k.a. turning) force points left at the moment we snapped these pictures.

The left track is flat. I’ve indicated the force the track exerts on the car with red arrows and labelled it ‘track force’. Gravity (which I didn’t show so as not to clutter the diagram) points straight down and exactly offsets the track force. That’s where friction originates.

But gravity and the track contribute nothing in the left or right directions that might help (or hinder) the car turning.

A graphic describing the forces acting on a car on a flat and on a banked track.

Now compare that with the same car turning on a banked track, which I show on the right side of the above picture.

Gravity still acts down. (Gravity always acts straight down.) The track force is still perpendicular to the track. But when the track is banked, some of the track force points in the direction of the centripetal (turning) force.

The banking actually helps the car turn.

Of course, there is a trade-off. A banked track provides slightly less frictional force. But the net effect is that a banked track allows a car to turn faster because the banking contributes turning force. The force from the banking adds to the force from the tires. The higher the banking, the more turning force help the track provides.

Talladega on ice

In fact, a banked track can provide so much help turning that it can compensate for a loss of friction.

Imagine a sudden, concentrated storm that covers Talladega’s Turn 4 with a sheet of solid ice. The tires don’t touch the track at all in that turn. There is no friction.

Because of the 33-degree banking, a car could still travel through turn four at Talladega at a maximum speed of just about 103 mph.

That’s not to say the car would be well behaved through the turn: It would be sliding instead of rolling and you wouldn’t be able steer – but you would make the corner.

At Martinsville, with only 12 degrees of banking and about a 200-foot turn radius, the maximum speed at zero friction would be only about 37 mph.

If a car travels too slowly around a high-banked track, gravity will pull the car down the banking. We will likely see that this week at Talladega, and next week at Dover, as well. Dover’s reputation as a ‘self-cleaning track’ originates from physics.

On a banked track, you have to move fast to beat your competitors – and to beat gravity, too.


Seven Cup drivers entered in Xfinity race at Sonoma


Kyle Larson is among seven Cup drivers entered in Saturday’s Xfinity Series race at Sonoma Raceway.

The race marks the first time the Xfinity Series has competed at the California road course. Teams will get 50 minutes of practice Friday because this is a new event on the schedule. That additional time will give those Cup drivers more laps on the 1.99-mile road course.

MORE: Sonoma Xfinity entry list

Here is a look at what Xfinity rides the Cup drivers will pilot this weekend:

The race is scheduled to start at 8 p.m. ET Saturday.


Winners and losers at WWT Raceway


Winners and losers from Sunday’s Cup race at WWT Raceway:


Kyle BuschWins the pole, leads the most laps and holds the field off over the last five restarts to win the race. He scored six playoff points, giving him 16 on the season, second only to William Byron’s 17. Busch left Joe Gibbs Racing after last season for Richard Childress Racing. Busch’s three wins this year equals what JGR has done so far.

Ryan BlaneyHis sixth-place finish moved him into the points lead. He last led the points after the spring 2022 Richmond race. Blaney also won a stage Sunday to collect another playoff point. He has seven this season.

Kyle LarsonFourth-place finish was a big turnaround after struggles earlier in the race. It has not been easy for this team the last few weeks. He has three top-five finishes and four finishes of 20th or worse in the last seven races.

Daniel SuarezHis seventh-place finish moved him up two spots to 16th in the standings, the final playoff transfer spot at this time.


Ross ChastainHe finished 22nd for his third consecutive result outside the top 20. He entered the weekend leading the points and fell to fifth afterward. He is 29 points behind new series leader Ryan Blaney with 11 races left in the regular season.

Tyler ReddickRebounded from an early spin to lead but had his race end after a brake rotor failed. He was one of four drivers eliminated by brake rotor failures. The others were Carson Hocevar, Bubba Wallace and Noah Gragson.

What drivers said at WWT Raceway


Here is what drivers had to say after Sunday’s Cup race at WWT Raceway:

Kyle Busch — Winner: “Just the restarts kind of went our way. We were able to get through on the outside on that one and push (Kyle) Larson out, then he took bottom of (Turns) 3 and 4, I was able to carry the momentum around the high side to take the lead. That was really important. I think that was kind of the key moment of us being able to win today. Being able to control the rest of the restarts for the rest of the race. Kyle is one of the best. It’s good to be able to sit up here and race hard with him, being a Team Chevy partner. He gave me great respect, I appreciate that. That will be given back down the road.”

Denny Hamlin — Finished 2nd: “Yeah, I thought we were super dialed if it was 95 degrees like it was supposed to be with those delays – it kind of took away from the advantage I thought that we had. I’m proud of this whole Sport Clips Toyota team – pit crew did a phenomenal job keeping us in it and doing really good on the money stop with about 60 to go. We are going to have to wait another to get that 50th (win).”

Joey Logano — Finished 3rd: “I’m proud of the fight. We were mediocre – just outside the top five all day long. There was a group of cars that were a tick better than us. Then we executed at the end and beat a few of them. We tried some new things from last year, and we learned some lessons. But overall: Good. We needed a solid run. We’ve been going through hell here lately. So, it’s nice to get a top five, third place, and some points there in each stage. Good day.”

Kyle Larson — Finished 4th: “Proud of the effort today. It’s been a couple tough races. We’ve been so good all year long and the last few have been pretty bad and we’ve had to work on it quite a bit. The team got us in a place where we could contend for the win, so you can’t ask for much more than that. …  I wish I would have done a better job. When I was the leader, I hadn’t been at the front all day, so I didn’t know what to expect. I didn’t know where people were running on restarts, and I didn’t know how hard they could go. I just got kind of caught off guard and lost the control.”

Martin Truex Jr. — Finished 5th: “Started off the race near the front and stayed there through Stage 1 and thought we could get a little bit better and maybe have a shot at the couple, three in front of us. We had a pit road penalty and had to go to the back, and it was just an uphill climb from there. Just really tough to get through the field. We got some damage from when someone’s brake rotor exploded, that slowed us down even more. Really with all we went through today, a top-five is a really good day for us. I’m proud of the effort.”

Ryan Blaney — Finished 6th: “We ran pretty good today. Won the second stage which was good, second in the first stage. Just kind of lost track position, lost the lead. Through a couple stops and restarts, we could just never really get it back. I thought that (Kyle Busch, Denny Hamlin) and I were similar. It was just a matter of who was out front. I just got a bad restart at the end and fell to sixth. But overall, it wasn’t a bad day. It was a good points day too, and we’ll keep going.”

Daniel Suarez — Finished 7th: “The entire weekend was very solid for us. We barely missed the second run in qualifying and really, we missed it because of me and not because of the car. The car was capable of advancing. In the race, the car was strong right away. It was fun today and we really needed this as a team. We needed a result that we deserved, and I felt like lately it’s been a little difficult on us when it comes to that. Today, I felt like we deserved a top-10 or top-five and we came home seventh, so we will take it.”

Michael McDowell — Finished 9th: “We kind of learned last year that track position is super important. Taking two tires was an option last year, so we knew it’d be one this year. We did it early on and got track position, but we got spun out. So, went all the way to the back and then we put four on, and then you’re just buried back there. So, we had to go for it again, put two on and just left two on. We never took four again. There were a lot of laps on the left-side tires, but track position was super important. We had a great FR8 Auctions Ford Mustang, so I knew we could kind of hold our ground. Those last few cautions kind of hurt us a bit, but still came away with a Top-10. So, it was a good day.”

Chris Buescher — Finished 12th: “That was a long day – long race. There were a lot of cautions and red flags. It really started yesterday. I was in a little bit of a hole after qualifying, and I just didn’t do a good job. I had to dig out of that today. We had pretty good speed in our Fastenal Ford Mustang. I was pretty happy with it, and at times, had to move around the track quite a bit. I figured out Gateway really quickly. Not being able to run here last year, I felt a little behind getting going. Definitely found something there at the end. Honestly wish it was a 600-mile race because I felt like we could have kept getting better.”

Austin Cindric — Finished 13th: “Definitely frustrating having a speeding penalty … I’m a little frustrated with myself with that. You think something at the end of Stage 1 isn’t going to affect your race, but it just put us behind. We tried a bunch of strategy calls to get our Freightliner Ford Mustang up there. Had some good restarts at the end and made the most of it, I feel like. Those restarts got really scrappy. Proud of the team effort, proud of the recovery. Definitely a lot to clean up on my end to maximize what I thought was a Top-10 race car.”

AJ Allmendinger — Finished 14th: “We had an up-and-down day today fighting the balance in our No. 16 Chevy. I felt like we had a top-15 car most of the day, but we had to play defense to stay there. I wasn’t able to roll speed through the corner like I needed to be more aggressive and keep moving forward. We made a strategy call to take two tires, which didn’t work in our favor. Then we got caught up on pit road and restarted pretty far back at the beginning of the third stage. We’ll take a 14th- place finish after everything we battled with our car today and move forward to Sonoma.”

Justin Haley — Finished 16th: It was an up-and-down day for this No. 31 LeafFilter Gutter Protection team. We fired off tight in traffic, and it was just hard to pass. My crew chief, Trent Owens, made some really good strategy calls and we had positive adjustments all day, despite a couple pit-road mishaps. We had another good Chevrolet hot rod, and we will take a 16th-place finish after a hard fought day.

Ryan Preece — Finished 17th: “That was a really long day. I fought a tight race car all day long and every time we came down pit road, my guys made really strong adjustments. It just wasn’t enough to get us to the front and stay there. There were so many cautions there at the end, I was just trying to save the car. Overall, it wasn’t a terrible day for us after qualifying 29th. The fans were out in full force today, too, that was awesome to see. We’ve just got to keep grinding for better finishes.”

Erik Jones — Finished 18th: “Just an up-and-down day for the No. 43 Bommarito.com Chevy team. Didn’t end up how we wanted it to go, but we’ll go to work and get the car a bit better. I thought we had good speed, just didn’t have things go our way. We’ll work on it and hopefully go to Sonoma (Raceway) and have a solid day.”

Aric Almirola — Finished 19th: “We battled handing issues all day and just couldn’t find it. We were loose to start the day and it felt like our car was tight on aero and loose mechanically. Our long-run speed was really all we had today and we could pass cars late in the run, but we had so many cautions in the final stage we didn’t have the chance to run those cars down. Drew (Blickensderfer, crew chief) put me on offense on the last 20 laps with fresh tires and I thought we could’ve driven up to 15th, but someone missed a shift on the last restart and stacked us up and put us behind. Just one of those days. We had to battle to get all we could get.”

Ricky Stenhouse Jr. — Finished 32nd: “We kept our track position just like we wanted to. We got stage points, and I felt like we had a top-eight or so car, which was a big difference from last year. Obviously we’re striving to be better everywhere. We had a really good streak going of really good runs. It looked like the No. 2 (Austin Cindric) just, for some reason, right-reared the No. 3 (Austin Dillon) and took both of us Chevy guys out, so that’s a bummer. We definitely had a top-10 car today.”

Tyler Reddick — Finished 34th: “Our day kind of went bad early on, but our McDonald’s Camry was able to get through traffic pretty well, but as the track stated to cool off, it just started going away from us. It was starting to get frustrating out there for sure, to have a car that good, and it felt like it was just going away. I had a bad feeling that was coming soon. I was just getting ready to have to back off with how soft the brakes got, but I obviously should have been thinking about that a lap or two sooner.”

Carson Hocevar — Finished 36th: “I thought it was great. I had a blast. Just so thankful for the opportunity. I don’t have a job for next year. I know Al Niece and Cody Efaw wants me to run for them and I will forever run a race or however many. But man, I’m just so thankful that they gave me the opportunity – the opportunity to drive a Xfinity car and now driving a Cup car. I was running 16th.. just so surreal for the first time ever. I thought we were going to have a good day and be in a good spot for Schluter Systems, Celsius, Spire Motorsports, Ryan Sparks and the No. 7 Chevy team. Hopefully that call for a Cup ride isn’t the only one I get in my life.”

Cup results at WWT Raceway, driver points


Kyle Busch scored his third Cup victory of the season, winning Sunday’s Cup race at WWT Raceway in overtime.

Busch is tied with William Byron for most victories this season. Busch and Byron have combined to win three of the last six Cup points races (two by Busch and one by Byron).

MORE: Cup race results at WWT Raceway

MORE: Cup driver standings after WWT Raceway

Denny Hamlin finished second. Joey Logano placed third. Kyle Larson overcame struggles early in the race to finish fourth. Martin Truex Jr. completed the top five.

Corey LaJoie finished 21st, driving the No. 9 for the suspended Chase Elliott.

Ryan Blaney placed sixth and took the points lead from Ross Chastain, who placed 22nd. Chastain fell to fifth in the standings.