Race Weekend Central

Tech Talk: G-Forces, Sway Bars & Inspection Failures with Jason Ratcliff

Being in the Chase adds a whole new level of pressure for NASCAR Sprint Cup Series teams. Not only can a bad race back a team into a corner, but the scrutiny of the sanctioning body to make sure everyone is on a level playing field also puts teams under a huge microscope.

This isn’t the first time Jason Ratcliff, crew chief for Matt Kenseth, has been down this road, but it seems like the latest rule changes are ratcheting up the pressure even more.

In this week’s Tech Talk, Ratcliff touches on sway bars, truck arms, shocks and springs. He discusses vertical and lateral loads along with pit road timing lines. He also gives us a detailed explanation about the tolerances and measurement minutiae that applies to these teams when they cross the Laser Inspection System platform at the end of races.

Mike Neff – As you debrief from Chicagoland, what is your take on the race?

Jason Ratcliff – I thought it went good. I feel like the mile-and-a-half program for the [No.] 20 car used to really be our strong suit. It’s not bad, but it is not what it used to be in comparison to the competition. It is something we’ve been working really hard on. I felt like in Chicago we a made some gains on it and had a good run. We had a couple setbacks with some pit road penalties and getting caught on pit road during a green-flag cycle. Matt was able to pass cars and work his way back to the front. If we don’t get in the wrong spot on the final restart I feel like we come out of there with a top 5. It isn’t too bad for a start to the Chase. It is something we can build on.

Neff – The track in Chicago has aged a good bit, and you had tires that fell off but didn’t fail aside from a couple of odd failures for a couple of guys. The tires seemed pretty sporty and let you race all over the track. Did you feel like you could work from the top to the bottom pretty well?

Ratcliff – It seemed like it. Usually the longer the weekend goes the more the track widens out. We kind of saw that on Saturday during the second practice. During the race it widens out even more and gives you some options. When the tires are new the short way around the track is still the best. However, you get some long green flag runs there, and that makes for some good racing there. I felt like it was the same old Chicago. I know a couple of guys had some issues. I don’t know want that was about. Everything we had looked really good.

Neff – You’re headed northeast to chase that giant lobster. When you roll into New Hampshire there’s almost always talk about getting through the middle of the corner. Is that still your No. 1 priority?

Ratcliff – It is; as the track takes rubber throughout the weekend, and usually the way the practice schedule is laid out we’ll usually see the hottest conditions during the race. However, this weekend forecast looks like it is going to be nice and cool on Sunday. Center turn is paramount, and that is what will get you to the front and ultimately gives you an opportunity to win the race if you get that right.

You have to optimize the grip ability of the tire. You want to keep maximizing to ensure the front tires keep working. You don’t want to get the car turning with the rear axle. You want to keep that under the driver so he can get in and off of the corner. You have to keep the front tires working. It isn’t too big of a task for five or six laps, but to keep those things working for 40- or 50-lap runs and stay working can be a chore. That is where the center speed comes from, maximizing everything across the front of the car to get the front tires working the best.

Neff – In that vein, we don’t seem to hear as much about them as we used to, whether it is the height rule or overall rigidity of the car these days, but that is where the sway bars come into play. At this point in the evolution of this car, is the sway bar near as important as it used to be three or four years ago?

Ratcliff – It is, it is just different. With the no-ride-height rule that came about a few years ago, you can set the car down. That enables you to keep the platform really nice. You don’t get as much travel as you used to because the cars are starting so much lower. The sway bar is still a key piece of the setup, but maybe in a different aspect from what it used to be because the travels are so much less than they used to be.

Neff – There isn’t much banking at Loudon, which makes your challenge different in how the car attaches to the racetrack. Are there things you do differently in the car on a flat track to help the tires hook up?

(Photo: Nigel Kinrade/NKP)
Ratcliff and Matt Kenseth enter New Hampshire with two-straight wins at the mile oval. (Photo: Nigel Kinrade/NKP)

Ratcliff – It is just a different approach. The mid-corner speeds are going to be a lot lower.  You don’t have the vertical Gs pushing you down into the racetrack. Working with left-to-right spring combinations, and as you mentioned earlier sway bars, and shocks and really the whole thing. It just takes a different mindset going into a flat track vs. a track that has more banking like we had at Chicago last weekend.

Neff – Is the interaction of the truck arms with the rear end the most important part of getting the horsepower all of the way to the ground?

Ratcliff – It is significant. At these bigger tracks where your off throttle time isn’t as long and the RPMs don’t fall down as low as they do at a place like Loudon or a short track, truck arms don’t have as big of an effect. Especially when you talk about the height or the difference between left and right. When you get to Loudon or where we were in Richmond a few weeks ago, it is a nice tool to be able to make adjustments. You can tune in the balance for the center as well as the exit on throttle grip for the corner. It is a big part of it, just like right rear spring and right rear shock is something we focus on a lot more at a place like Loudon than maybe we would at Chicago or Charlotte.

Neff – We saw a bunch of timing pit road issues in Chicago since NASCAR added the additional timing lines. When you approach the weekend, do you have to back it down an RPM or two in order to build in a cushion for the fluctuation a driver is naturally going to have with their foot going down the pit lane?

Ratcliff – We just have to be more mindful. Before you had a little wiggle room, especially as you approach and leave the pit box. The segments were also bigger so, if a driver felt like they were speeding, he could give it back. He had time to slow down and get the average for the length of the segment back down to where it needs to be. With the shorter segments you don’t have the give back time. You don’t have the opportunity to get in and out of the box with more leeway. It is easy to get busted. You saw it last week with us.

That is exactly what happened to us. You have to take that into consideration. The way you pick pit boxes now is a little different. You don’t have those few pit boxes that are really somewhat of an advantage anymore. Now the advantages are pretty much the openings. There really are no timing line advantages that there used to be.

They have kind of taken some of the fun out of it. It used to be if you qualified in the top 7 to 10 you had an advantage picking a pit stall that might find you some time on pit road. Now, if there are four openings on pit road then the top 4 guys are going to have an advantage and everyone else is in the same boat.

Neff – We’ve heard enough about laser inspections the last couple of weeks and cars being out of tolerance. We haven’t heard a lot of discussion about what those tolerances are. Since the rear end was the issue at Chicago, what is the measurement NASCAR is looking for on the rear endm and what is the tolerance that is allowed after the end of the race?

Ratcliff – Well, pre-race you can be as much as three-tenths of a degree on one side and six-tenths of a degree on the opposite side. You can’t have more than the three-tenths on the minimum side or six-tenths on the maximum side. You can be under that as much as you’d like. Post-race they give you, I want to say it goes from .6 to .74 degrees on the maximum side and it goes from .3 to .44 on the minimum side. They give you .14 degrees for maximum tolerance. Now you can be anywhere under that, obviously, and be OK.

There are tolerances on every component under the car. When you go back to the tech center and they take your car apart and they measure everything, you have to meet tolerances on all of those. So even if you are good and you cross the LIS post-race, and you are OK and meet their requirements, you still have to go to the tech center. If you have a part there that is out of tolerance, it is still a failure. It is just another way of measuring.

The question I get asked most is: how can a car go across the platform pre-race and be OK and then come across it post-race and not be the same? A lot of things play into that. It is really more complex — even though there aren’t a lot of parts and pieces, there are a lot of joints that get bolted together. Each one of those gets bolted together and has a small tolerance. The next joint gets bolted together and there is a small tolerance. The wiggle room or tolerances they’ve given you are adequate. There is another variable there that is still in question. Maybe they’ve given us enough tolerance for that as well, and that is just the platform itself. There is a little bit of variability there but, in NASCAR’s defense, I hate to use the word defense but speaking for NASCAR, they give you plenty of opportunity to go across the platform throughout the weekend. They do give you a tolerance. So, it is up to you to hit it. We’ve been guilty of missing it as much as the next guy. It really comes down to, like everything else, you have to push right up against everything to be competitive because your competitors are going to do that. At the same time you have to be smart at this point in the season. 10 points can be a big deal.

We’ve gone up there when we felt like we were going to be more than safe. We had done everything that we thought we needed to do to be very conservative and been extremely close. Things move around on a racecar. Throughout the course of an event for 400 or 500 miles you can get bumped here and there. Let’s face it, all of the wheels are not the same, they’re just not. You can put on four or five different sets of wheels and get different measurements. We do our best to make sure all of that is as consistent as possible but the reality of it is it is a man-made part and it is only going to be so consistent. We know what we have to work with and I think we see a lot of guys failing it because everyone is pushing it really hard. You’ve got to if you’re going to go out there and compete to try and win races to move onto Homestead you’re going to have to be aggressive.

About the author

What is it that Mike Neff doesn’t do? The writer, radio contributor and racetrack announcer coordinates the site’s local short track coverage, hitting up Saturday Night Specials across the country while tracking the sport’s future racing stars. The writer for our signature Cup post-race column, Thinkin’ Out Loud (Mondays) also sits down with Cup crew chiefs to talk shop every Friday with Tech Talk. Mike announces several shows each year for the Good Guys Rod and Custom Association. He also pops up everywhere from PRN Pit Reporters and the Press Box with Alan Smothers to SIRIUS XM Radio. He has announced at tracks all over the Southeast, starting at Millbridge Speedway. He's also announced at East Lincoln Speedway, Concord Speedway, Tri-County Speedway, Caraway Speedway, and Charlotte Motor Speedway.

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I sure wish Jason would adjust my sway bar

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