Tech Talk: Mike Wheeler on Bump Stop Material, Hard Landing & Pit Road Practice

A typical Talladega race ended with some people thrilled, some people angry and others just disappointed. For Mike Wheeler and the No. 11 team, it was a disappointing race thanks to self-imposed difficulties after back-to-back pit road speeding penalties with driver Denny Hamlin. Looking to rebound, the team is preparing to head to the first state and take on the one-mile, concrete racetrack at Dover International Speedway.

This week in Tech Talk, Wheeler talks about the unique challenges that Dover presents. From dropping into the corners and the strains that put on the bump stops to launching up and out of the corners having the car become “tall and light.” Wheeler also looks at practicing for one of the trickiest entrances to pit road and how that changes during race action. He also analyzes ride heights, getting too low and making things comfortable for the driver. All of that and more in anticipation of 400 laps on the high banked mile of Dover.

Mike Neff, Frontstretch: It was another restrictor plate race. In the end, how do you feel like it went for the No. 11 team this week?

Mike Wheeler: I think we had a top-five car most of the weekend. It drove ok, a little free, the first run or so. We worked on the balance quite a bit on the first stop and got it definitely competitive. It seemed like we didn’t have enough teammates up front to run with the Ford group and battle with them. We had moments of leading laps and running up front and battling for top five positions. Had a pit road penalty that got us really behind and we just didn’t have enough laps to recover from that.

Neff: You mentioned feeling a little free. It seems like that is coming into play a little bit at Talladega now that the asphalt is starting to age a little bit. We always hear that Daytona is more of a handling track than Talladega. Do you feel like handling is starting to become a factor again there?

Wheeler: I’m not sure how much that is the pavement aging or the new aero package we have with no ride heights. The cars were obviously a lot lower in the race this year than they were last year. Tire changes and all of that kind of stuff comes into play as well. I think a lot of it had to do with total aero balance and grip from what we had in the past.

We worked on it some but obviously, you never get the true sense of where you are at until you go racing for a couple of stints. Burn fuel off, get on hot, old tires, race around a bunch of guys. I think a lot of us had the same complaints. We got our notes in line from there and we’ll be a lot better come playoff time.

Neff: I saw a tweet this weekend that said: “Death, taxes and Denny Hamlin speeding on pit road.” It happens to him quite a bit, but is it something, especially at Talladega, that you’re willing to take that chance because generally, you can recover from it?

Wheeler: It is one of those things. It is never really worth speeding. I can say we’ve never actually tried to speed in the last year or so. We played some games back in 2016 trying to maximize what we could before we had all of the data that we have now. Ultimately Denny tried to race the No. 22 into pit lane for that last green flag stop, which was basically racing for the win. If you come off of pit road first there you are in the best position of anyone to win. Just got caught going a little too deep and rolling that first segment a little bit too fast.

It is one of those things, people are like “Why didn’t you just slow down more?” You already picked your braking point and you’re already charging entry. You can’t slow down any more than you already have. It is kind of like braking at Martinsville. If you pick your braking point and you charge into the corner and you miss that point by five feet, you end up sliding up the corner. For pit road entry you end up too fast on pit road and get the penalty. It was nothing small. We repeated it the second time, the next time by with another one but it was a similar deal.

Hot brakes at Talladega is something that we aren’t used to. That time he had hot brakes and wheel hopped it and had the same thing, so it was a double whammy. Lesson learned, we definitely had to take it on the chin. Something we haven’t had a problem with lately. We have a hindrance of having pit road speeding penalties but it is something we’re taking to heart and working on really hard.

Neff: Now we head off to Dover that some people call a short track because it is one mile long, others claim it isn’t. The track surface is concrete. Does the different surface than normal throw any challenges at you?

Wheeler: For sure. The concrete surface is different from most tracks. Obviously, the coarseness of it is something. It and Bristol definitely are a little different animal in how the rubber adheres to it. You can see it too, as it goes from white to black and the rubber packs up. Some of the joints between the concrete sections can be an issue. You feel them and as the rubber clumps up there it can be a little bit different as well. The good thing about it is, as the sun comes and goes, it doesn’t change as much as the asphalt track do.

Neff: The corner entries, you kind of drop into the corners. There is already a lot of load on the suspension to begin with, does that landing cause even more stress on the stops and suspension components as the race goes along?

Wheeler: Over the years we’ve had mechanical load issues and we see them a lot of times at Dover and that is where we find our weak spots. When we went to bump stops, we’d have our issues first at Dover and then find them at other racetracks. The landing loads you see at Dover is some of the highest you see. Dover is also good for having high right front loads and you can see loose wheels show up often as well. It is crazy that it is only a mile but the impulse load you get from landing is one of the top tracks out there.

Neff: In Tech Talk, we’ve talked about the different materials that are invoked in making bump stops. Because of the high loads is Dover one of the tracks that lends itself to the metallic bump stops?

Wheeler: It is one of those things that you can definitely play around with. We’ve found a lot of durability lately in using springs instead of using rubbers. A lot of the rubber materials end up changing with heat and load and can also have durability concerns. It is back and forth. You can find some good handling characteristics sometimes with rubbers but at the same point, you’re always questioning if they can actually make that many laps with those kind of loads at Dover.

Neff: As you get around the corner and you get ready to come onto the straights you get the moment where you launch out of the corner and the car tends to lighten up. Is that something where you have to make mechanical adjustments to keep the car as planted as you can?

Wheeler: Definitely, we call it over the rise on entry and on exit. The car gets pretty tall and pretty light. Most of our aero gains and CG (center of gravity) gains are from running the car lower. As you go through the transition you end up for sure in uncomfortable attitudes for the driver and the tires too. You’re always trying to fight that balance of making the car stay down on entry.

Obviously, you can’t just lower the car more because you end up loading the car up too much in the middle of the corner you can end up too low. As much as you want to stiffen the car, the place is rough enough that you fight the balance of being too rough and too stiff. It definitely is a track of its own. It has all of the different characteristics that you want to chase. It has ride heights and entries versus centers and balance and roughness that make a racetrack unique.

Neff: You talk about ending up too low. Is that a scenario where the splitter hits the ground and it releases the load on the front tires so you slide up the track?

Wheeler: A lot of times you end up going off on entry, especially on restarts, when you’re low on air, and you end up crashing the splitter or the back of the car and easily take load out of the tire, which disrupts your aero. It is touch and go with how much you can get away with and how hard you can do it. Some guys try and ease up entry and not crash the splitter too hard, but a lot of times you need to charge hard on the restart and you end up having to race as hard as you can to keep the position.

It is a balance there. You want to make sure you can go on the restart for the first five laps but you have to make sure you are good on the long run too because Dover is one of those tracks where you can get long green flag runs as well.

Neff: Restarts at Dover don’t seem to have as much of a preferred lane as other tracks. You don’t have to count positions leaving pit lane to try and end up in a specific lane do you?

Wheeler: Not necessarily. It seems like it is one of those tracks that widens out enough that you can make a couple different grooves work. A lot of these tracks you want to be on the outside for the launch or through Turns 1 and 2. Dover’s transitions, and the way it rubbers up through the corners, you can kind of maintain in both lanes as long as your balance is good for each of those. I am sure with different tires and different weathers things can change but, from my knowledge, it wasn’t one of those things that you want to chase. All you want to do is come out of pit road as high up as you can and make the first left as fast as you can.

Neff: We hear it at a lot of tracks throughout the year but there is no doubt the entrance to pit road at Dover is very tricky. Is that something that you work with Denny during practice leading up to the race just to get a little practice with it just to make sure you have it down before the race starts?

Wheeler: Obviously, with the Talladega speeding penalty last week we talked about it on Monday. Coach (Joe Gibbs) came in to ask us what we could do more just to avoid the penalties. The interesting thing is that Dover is one of the trickiest entries there is. It reminds me of Darlington. You think you can get down there to pit lane, but you’re going so fast and the entrance is so slick with different banking that you end up in trouble pretty quickly.

We’re going to try a couple different chances at it during practice. The interesting thing is that it isn’t the same as what you have in the race. Generally, during the race, you go longer on tires, you’re lower on fuel. Pressures have built up and the tires are hotter so when you go to do your pit road entry during the race there is just a whole lot less grip. You might do it 10 times during practice and feel really good about your marks. In the race, when you do a full green flag fuel stint, you’re definitely going to have to back up your entry in order to make pit road appropriately, otherwise you’ll end up missing pit road or speeding on entry.

Neff: You mentioned tire pressures. At some track, especially the flatter tracks, you can go super low on tire pressure to start the runs. As you talked about earlier, you’re landing really hard when you go into the corners at Dover. Do you have to start pressures a little higher because you land so hard in the corners?

Wheeler: Goodyear gives us recommendations where to be for minimum air pressures. Obviously, with the loads you have in the corner at Dover, even though it is a mile, you’re not anywhere close to as low as you are at Phoenix and Loudon. You’re definitely more inflated and have to keep the air in it. The amount you are deflecting the tire at low air is dangerous. It builds a lot of heat in the tire and you can damage the tire pretty quickly. You have to keep them inflated. As much as you want to keep them low for the long run you have to make sure you don’t damage the tire early in the run and make the full stint on the tires.

Neff: Similar to Bristol you have this high banking, which kind of catches the car as you come into the corner. That takes a little stress off of the brakes. Are they ever much of a concern at Dover?

Wheeler: You have just enough braking at Dover, with short enough straightaways, that you have to run just a little bit of brake duct opening to keep them cool. You don’t necessarily wear the brakes out per se, but temperatures between rotors and pads and calipers can get too hot and having brake fade is a concern. It isn’t like a Martinsville deal or Pocono where you run out of brake pad and you feel like you can fail the brakes. You can definitely get a long pedal or soft pedal from getting the calipers a little too hot and you have to balance that out with concern to total grip and the brakes.