Tech Talk · Mike Neff · Tuesday July 10, 2012
The Cup Series heads to Loudon, New Hampshire for the first time this season this coming weekend. Last year the Stewart-Haas Racing team owned the track, with Ryan Newman winning the pole position for both races along with winning one of the two while his boss and teammate, Tony Stewart, took the trophy in the other. Newman’s crew chief Tony Gibson is our guest for this week’s edition of Tech Talk and talks about the importance of aerodynamics, mechanical grip and rolling the center of the corners.
Mike Neff: New Hampshire is about the flattest track that we go to. Do aerodynamics play any kind of role in getting through the corners there or is it all mechanical?
Tony Gibson: Aero comes into play no matter where you go. Loudon is one of those unusual places where you’re running pretty fast down the straightaway and having sideforce and downforce helps more for corner entry than it does anything else. Once you get to the center of the corner, aero plays a little bit, but getting into the corner is when you’re trying to utilize the sideforce and downforce. It plays a pretty good sized role at that race track because it is so fast. Even though you’re flat in the corners you think it is a slow track, but it isn’t. Anywhere else like Bristol isn’t so bad because you have the banking that picks the car up and forces the tires down onto the ground and gives the car grip. At New Hampshire you’re asking the downforce to hold the car because you don’t have that vertical load.
Mike Neff: There is always talk about ‘rolling the center,’ but we hear it more at New Hampshire than anywhere else. When teams refer to rolling the center of the corner what are they talking about?
Tony Gibson: It pretty much means the time in the corner when you’re off of the throttle. At Loudon you use a lot of brake getting into the corner, so you try and do a lot of your braking as straight-line braking. Then you want them to get off of the brakes and let the car just roll through the corner. Being able to have the car free enough so that it isn’t mechanically bound up as it rolls through the corner and free rolls through the corner.
You have the old cup theory where a Styrofoam cup or a paper cup is smaller on one end than the other and that lets it roll around a corner. You get wedge out of it and track bar up and things that can mechanically unbind the car that will allow it to roll through the center. Physically being able to get off of the brake as soon as you can and let the car carry that speed through the center of the corner gives it the momentum that lets it keep rolling and you don’t have to get on the brakes again to get the car to take a set or slow it down enough to make the corner. That’s what guys are talking about, they just want to hit the brakes, get it whoa’d down to a decent speed and get off of them to let the car roll through the center without having to feed a bunch of wheel to it or get on the brakes again.
Mike Neff: You spoke about mechanical grip. What kind of things do you have to do to the car on such a flat track to make it hold a corner?
Tony Gibson: A lot of it is cambers. We try and run as much camber as we can in the front end so that the car rolls into that camber in the corners to get the most tire patch on the ground as possible. It is critical at a flat track because the more tire you have on the ground is more grip. Front cambers are really crucial at places like Loudon where it is really flat, Martinsville is the same way, Richmond, Phoenix where you’ll hear people talk about too much camber and tires blow because of too much camber. Guys put that much camber into their setup to try and make sure they have the widest footprint possible with the whole tire on the ground in the corner.
Mike Neff: For qualifying at New Hampshire you guys have obviously got that figured out a little bit since you sat on the pole twice last year and Newman set the track record last year. What do you change for qualifying to make the car fast for a lap or two, obviously not giving away inside secrets, but that are standard things changed?
Tony Gibson: A lot of it is the stability side of things which is nose weight, track bar, things that will put mechanical grip into it. You have so much grip in the tire itself that to use that grip and run faster, you have to offset that with nose weight. We drop the track bar in the back. We put some wedge to it. Things that will just build in a lot of mechanical grip in the car for just one or two laps. Nose weight, track bar and wedge are our three biggest hitters and that is pretty much all we change when we go to qualifying. We just find a delta from race trim to what we need to keep our qualifying trim, just off of past history there. We use our simulation programs to match that delta, whether it is a percent or a percent and a half tighter than our race run. We have a target that we try to hit and that is some of the tools we use to try and hit that.
Mike Neff: We’re heading into New Hampshire with another new rule adjustment with the side skirts. You spoke about sideforce getting you into the corners. Will this latest change in the side skirts make it harder for you to get through the corners and make the racing closer?
Tony Gibson: I think it is going to make a difference. I don’t think it is going to be as big as it is at Charlotte or Kentucky or places like that, but it is going to make a difference. The reason I say that is places like Loudon we run pretty soft springs there anyway, so the car gets down in the corners and squats so we’ll get some of that back off of the side skirts. We’ll never get back to where we were, but with the spring packages and shock packages we run at that type of track, we’ll get some of it back but not all of it. It is going to make a difference, the side skirt stuff is going to make a difference everywhere we run, but I don’t think it will be as big as what we saw at Charlotte and Kentucky and places like that.
Mike Neff:We’re hitting a stretch of flat tracks here with Loudon, Indy and then Pocono. Are there setup pieces that carry over from Loudon even though Pocono and Indy are so much bigger?
Tony Gibson: Yeah, I think the one thing we focus on at Pocono and Indy that we can relate to Loudon is turn three at Pocono and all four corners at Indy being flat and the same style of track as Loudon. The speeds will be different obviously, but turn three at Pocono is what everyone focuses on because that is the passing corner and trying to make the front straight as long as possible. Those are the corners that make those three tracks similar and Loudon, being flat allows several things to carry over to those other two tracks.
Mike Neff: It has been hot and they’re talking about it being hot in Loudon again this weekend. Are there changes you have to make to the car, outside of driver comfort, but mechanically to the car to change the handling because of the faster tire pressure builds and things like that?
Tony Gibson: Well that is just it, the biggest thing we deal with when the weather is really hot or really cold is air pressure in the tires. Any tire, even on your car at home, is affected by high or low air pressure. Now a lot of people have these new cars that have sensors that will show that tires are low on pressure, and you can go all summer and never touch your tires and when winter rolls around you have a message that your tire is two pounds low on your dash. It isn’t the fact that your tire has lost air, it is just that the pressure is lower because the air in the tire is cooler. Tires build pressure with heat. My wife tells me all of the time that her tires are low and I tell her that they’ll build up once the tires get hot. It is the same thing in race cars, when the tracks are hot and slick if you have a lot of air in the tires they build more quickly because of the heat. We have to adjust to that. We’ll adjust our pressures accordingly to how much we want them to build to by the end of the run. We may take two or three pound out, knowing it is going to build to the same amount by the end of the run, so we have to be careful not to put too much air in them on hot days. We back off of that a little bit and try to make up for that when it is this hot.
Ryan Newman and his No. 39 team have one win which, thanks to tie breakers, has them on the outside looking in at the wildcard positions for the Chase. Loudon has been a great track for them over the recent history of the sport and should give them a great opportunity to get a leg up on the other drivers trying to get in the Chase via wildcard. Provided Gibson makes the right tire pressure decisions, puts the correct amount of camber in the front geometry, and sets the wedge and track bar to make the car roll through the center of the corners successfully.
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