Viewers of Sunday’s Big Machine Music City Grand Prix, the 80-lap NTT INDYCAR SERIES competition on the streets and Cumberland River bridge of this Tennessee city might have noticed something different about the alternate tire prepared by single provider Firestone Racing for this event.
Where the alternate tire is normally red, this weekend it was a pale shade of green instead. Some were happy with the tire, others were not as the 80-lap contest progressed following a lengthy wait to start, after lightning from thunderstorms surrounded the city.
The alternate tires for this race were made of Guayule, a drought-resistant, heat-tolerant woody desert shrub that is native to the American southwest. Guayule produces rubber from its branches, its bark and its roots, resulting in the production of natural rubber for tires, resins for adhesives – as well as additives for tires and diesel fuel, together with a woody material called Bagasse, that results in energy, liquid fuels and building products.
Firestone is touting this material for its ecological benefits, following a 10-year investment – of over $100 million – to produce usable tires made of Guayule natural rubber. This rubber is produced in both the United States and in Mexico and replaced the company’s traditional alternate race tire for this race specifically. No doubt the intent is to get as much information as possible in order to acknowledge the benefits.
With the expectation that Guayule-produced rubber used in the alternate tire would give up the same wear tendencies and performance as a traditional Firestone alternate tire, Firestone presented teams with four sets of Guayule alternate tires, six sets of primaries and, thankfully unneeded, five sets of rain tires. There’s always an extra set of primary tires for rookies at every race.
The race was declared “dry” before the cars set out on the tires they’d opted to use before the weather set in, albeit more than an hour late after lightning strikes had been seen within the eight-mile stretch of land that INDYCAR uses to determine whether to race or not. That had the first five on the 26-car grid using the green alternate tires, hometown hero Josef Newgarden on primary, black Firestone rubber, and the balance of the field pretty much split between primary and alternate.
It’s apparent the primary Firestone tires were better overall than the alternates, but that’s not unusual. What was unusual was the introduction of a new product at Nashville, a notoriously tough street course that, many believe (after two races) needs a bit of revision to make it more racy. Oftentimes, drivers will do better with the alternate tire; it just wasn’t the hot tip for this track. Only a few drivers opted for the alternate tire a second time; notably Josef Newgarden, who finished sixth and Jack Harvey, the ninth-place finisher.
Still, Cara Krstolic, Firestone’s director of race tire engineering and production, believes the new tire has good possibilities for the future. “Guayule,” she explained, “is a fast-growing shrub that produces rubber in about every areas of the plant.” On the alternate tire, which had the same tread compound as the 2022 street course red alternate tire, “Our INDYCAR drivers can expect the same performance and durability as a traditional Firestone tire.”
The alternate, green tires didn’t have much bearing on the outcome of the Music City Grand Prix, which was won by six-time champion Scott Dixon of Chip Ganassi Racing, earning his 53rd career victory – after six pit stops and a penalty. As required by INDYCAR, Dixon used the alternate tire for only two laps during this race.
There are only three races remaining this year in the INDYCAR series, two on permanent road courses after the final oval contest at World Wide Technology Raceway outside Phoenix. For Portland and Laguna Seca, alternate tires will be used. But will they be red in color or green? And will they be made of Guayule rubber or some other donor material? Ms Krstolic noted, “The Music City Grand Prix was a great weekend for the competition debut of the Firestone Firehawk race tire made with guayule. The guayule race tires performed as expected,” she said. “Nashville was the only race we planned to run the guayule race tires for the 2022 INDYCAR season, but are looking at ways to use guayule again in 2023.”
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