From the Track Mid-Ohio

Firestone brings spilt compounds to Mid-Ohio

Story Credit: Jared DePouw
Photo Credit: Jared DePouw

One of the unique properties of the Verizon IndyCar Series are the availability of two different Firestone tire compounds during road course events. Primary tires are by design the standard rubber that teams will use for most of the weekend. In addition, Firestone has an alternate tire that teams are given in limited quantities. Alternate tires are made with a softer rubber compound and offers increased grip and the cost of reduced longevity.

The main way to tell the difference between the tires are by looking at the sidewalls. Alternate tires are painted red while primary tires are stock black. On a typical road course weekend, such as this weekend’s Honda Indy 200 at Mid-Ohio each team is given eleven sets of black tires and only four sets of red tires for the entire weekend. With almost three times as many black tires as red, proper management of tire inventory is critical.

Typically you would expect that a set of tires would be the same in terms of compound, but that isn’t the case with red tires this weekend. While the left side red tires are the same compound as the Indy GP, the right side tires have a brand new compound which is softer than the left side. So why would Firestone adopt a split compound on only red tires and not blacks?

“This is something that we have traditionally done at Mid-Ohio” said Cara Adams, Chief Engineer for Bridgestone Americas Motorsports. “It depends on what our compound profile and compound lineup looks like but this is certainly something we’ve done in the past as early as a few years ago.”

When you look at the layout of Mid-Ohio, eight of its thirteen turns are right-handers. “With a new track like Mid-Ohio you have predominantly heavier loaded left side tires because you have the way the track is set up you end up having a lot more load on one side and you end up driving the right side tires” continued Adams.

“So if you can do anything to make that right side softer, it ends up giving the overall car more grip.”

It’s interesting to note that Mid-Ohio is the unofficial home track of Firestone, given that the Firestone Tire & Rubber Company was founded over 100 years ago in nearby Akron, Ohio (only 75 miles away from Mid-Ohio)

Other interesting notes on tires this weekend include a much more significant difference between primary and alternate tires, which is something often requested by drivers and teams. Furthermore, there is a link between the increased grip from the alternate tires causing increased understeer. And with all but three cars starting the race on red alternate tires, expect to see the drivers starting on black primary tires (Hinchcliffe/Andretti/Bourdais) to be faster at the end of the first stint if green.

Jared DePouw
Jared is the founder of but works as a small business accountant. He also officiates high school football and lacrosse in his free time.

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