Putting a Damper on Arrow McLaren Racing SP

by The Earl of Indy, Robert Earl |

Don’t get me wrong. I think that this announcement has been one of the most exciting things that has happened to the IndyCar Series since the reunification. An organization with the racing heritage of McLaren rejoining the NTT IndyCar Series on a full-time basis for the first time since 1979 shows how much the Series is on an upswing.

All that being said, the key to success in the newly announced partnership between McLaren and Arrow Schmidt Peterson Motorsports with the creation of the Arrow McLaren Racing SP will hinge on one area.


McLaren brings a wealth of technology and resources to a series that has prided itself on being SPEC based Series.

Spec meaning that the NTT IndyCar Series “Specifies” and limits the components that can be used on the cars that take to the track. The Series mandates the use of a specific chassis, fuel, tires, safety components and even the use of either a Honda or Chevrolet powerplant that is closely regulated by IndyCar.

McLaren prides itself on building a Formula 1 car from scratch with components that might resemble those used by the other teams in F1, but custom to McLaren. Now they enter a world where they are boxed in on every side, except one.


What are Dampers?

Before we start in on Dampers, let me explain the process and how Dampers fit into the overall picture.

A driver gets into the car. The driver steps on Gas Pedal. The engine generates power. The power is transferred to the four wheels. The four wheels make contact to the track via the tires. All of this is the same for all teams because of the specs. Same Gas, Same Engine, Same Wheels, Same Track.

And all of this is pretty straight forward as long as the car is sitting in one place or going in one direction.

But what happens when you through in a turn or two and your add uneven surfaces. And with an apology to all of the drag racers out there that go in a straight line, the real challenge comes in when you add curves.

Frankly, that is true of many things in life, but I digress…

When the car is just sitting on the ground or going in a straight line, you get a consistent contact patch between the tire and the track, allowing the maximum amount of power to be directed to the track, propelling the car forward. This also applies when the driver hits the brakes. With the tire in complete contact with the track surface, then the brakes and tires slow the car in an efficient manner.

When a car is sitting on all four tires, the car is weighed in one of two ways. Either the car is placed with all four wheels on one large scale or each wheel is placed on its own scale, and the total weight of all four scales is the total weight of the car.

Why is the individual weight of each tire so important?

Racers from early on discovered that if they were going to be turning left, like they do 800 times during the running of the Indy 500, that the car was easier to turn if they started with more weight on the left side of the car. As a matter of fact, the car would not just roll in a straight line. It would actually start to veer to the left. This would aid in turning and make the car go faster.

Don’t worry; I will get to Dampers in a bit.

On a speedway like Indy, the car itself, minus fuel and the driver weighs approximately 1590 lbs. To start out, the team may set up the car so that 60% of the total weight starts on the left side of the car to aid in the turns. They do this by the placement of components on the car and the fuel tanks, etc.

But what happens as soon as the car enters the turn.

Think of it this way, while the car is trying to turn left, the weight is trying to roll to the right side of the car. First from the left side of the car to the right front of the car and then shifting from the front of the car to the back right of the car as it exits the turn before settling back to the center or left side of the car.

Now it is impossible to place four scales exactly under the four wheels at the exact moment that a car is in a specific place in a turn so that the crew knows the weight ratios during the turn. So they are left to guess.

They do not just want the car to “rollover” with all of the weight on the right side. They want the tire to remain in contact with the track, but not get overused. And the suspension will push back against the car and where it is connected to the chassis. This push back was originally controlled by springs and struts, then shock absorbers and now with modern Dampers. (told you I would get to them)

#13 and #19 in this Figure for the Rear and Front Dampers.

And here is the thing about the 2019 and 2020 IndyCar. The IndyCar series does not specify which Damper you can use or more importantly to the team, what can be done inside of the Damper to control the roll and push back.

The Damper is IndyCars Black Box and the engineers at McLaren are about to be tested as they have never been tested before.

You and I can buy a set of Dampers from a company like the Swedish Ohlins brand or the Penske Racing Shock company for $30,000 to $40,000 per set. Now keep in mind, this set will have a specific setting for how much compression and push back it delivers. So in order to run a specific type of track like an oval, a team may need 3 to 4 sets to make changes on the fly. Think soft, medium, hard settings. (I am not even going down the path of settings for Road Courses or Street Courses or short ovals vs. superspeedways.)

And just because you bought a set of Penske Racing Shocks, don’t think that your shocks will have the exact settings as ones running on the Team Penske cars. No. Once you get a set of Dampers, it is up to you to make the changes to adjust the compression and push back.

So you buy a set of Dampers. Now What. This is where telemetry and practice and testing comes into play. But testing is restricted and practice on a race weekend is limited unless you have a rookie driver on the team. (This is another story for another time – stay tuned)

So let us jump back to the example of the car going into the turn and the weight shifting from the left side fo the car to the right on an oval. Ideally, we do not want this to happen, so we want the car via the Damper to push back against the forces so that the weight does not shift and it remains stable and centered. The Damper has to have a setting that allows for it to compress a bit to absorb the initial load but then push back against the forces. During testing, the team will install telemetry sensors that will monitor the forces. These forces are calculated into the shifts that occur in weight and the counterbalance that needs to occur. This calculation will be based on the amount of pushback that is needed. But track time is limited. Years ago there was no limit to the amount of time a team could test at certain tracks. Now the IndyCar Series, in an attempt to lower overall cost for all of the teams, specifies how much testing can be done.

Auto Racing began 5 minutes after the second car was built.

Henry Ford

Testing at the track that is.

Enter off-track testing, computer simulation, and computer testing.

If the car enters the turn, and this much force is transferred, and we want it to transfer back then we will build a machine that simulates the wheels going up and down and make adjustments to the Dampers after each lap to see how much it changes the pushback and we will do it over and over again until we get the setting we need and also will measure what it does to the other tires.

The teams do this using a tool called a “shaker rig.” The shaker rig is programmed with the data from the previous time that the car ran on the track from practice or testing. The shaker term comes from the fact that the four wheels are moved with the forces and compressions measured from an actual previous run on the track.

In this video, you can see the car shaking because of the piston like forces being pressed upwards into the tires.

These rigs are also referred to as “seven-post rigs” because they operate on seven hydraulic cylinders.

So a team has a choice. The team can buy a shaker rig and test the cars anytime that they want, but there is a catch. To build and maintain a shaker rig would cost millions of dollars. Teams don’t usually make that investment. They end up renting time on the rig from Auto Research Center in Indianapolis or Ohlins in Hendersonville, N.C (near NASCAR Team shops) at a going rate of $7k to $10k or so a day.

And even if you had a rig or rented on, it is going to generate data. Lots of Data. And the team will need to know what to do with the data, and how to use it to make productive changes. Changes to Dampers in particular. So you need smart people. Racing has always been a people-driven sport. Smart people like Ray Harroun that installed the first known rearview mirror so that he didn’t have to carry a riding mechanic to look behind him. But smart people cost money.

And nowadays, smart people write computer programs to help them interpret and utilize the data. To create simulations that allow for instant feedback.

McLaren Technology Group has a wealth of these types of people. So despite having a year left on his agreement with Honda, Sam Schmidt made the business decision to align himself with McLaren. And after the showing in May at Indianapolis, Mclaren needed the race-proven expertise of Arrow Schmidt Peterson Motorsports to put that technology to work on a proven team that needs help to get to from being a second-tier team to one that competes week in and week out. And the main area they can help is Dampers.

This is part of the reason that Andretti Autosport has a group like Andretti Technologies. https://www.facebook.com/AndrettiTechnologies

These smart people and resources are critical to a team like Harding Steinbrenner Racing that can tap into the expertise without making the entire investment themselves.

Don’t get me wrong. Harding Steinbrenner Racing does not know any more about what changes are made inside of a Damper today than they did at the start of the season. They are given a set of Dampers by Andretti Technology, and they are told they are soft, medium, or hard and will work on this type of track. But as a young team, this technical alliance was a key to them visiting victory lane in 2019 along with a great driver.

Chip Ganassi Racing has also considered the idea of creating a Technology Group to work with other teams.

All of this in an attempt to collect more data.

When I asked Zak Brown, CEO of McLaren about the McLaren presence at the track for the remaining four races of the 2019 IndyCar Series, he indicated the following:

You’ll see Gil de Ferran at all the remaining races, as well as a couple of engineers and data analysts. Towards the very end of the year, you’ll see people from communications and marketing as we look to review things from a branding and activation standpoint. So I think you’ll probably see half a dozen people from McLaren at each race moving forward.

Zak Brown – McLaren

My key takeaway from his response: Engineers and Data Analyst.

Let the Damper development begin.