Goodyear ups recommended minimums for Indy
July 23, 2014, David Caraviello, NASCAR.com
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This season's Sprint Cup Series rules package combined with a demanding Brickyard layout have led Goodyear to make "significant" increases in minimum recommended air pressures for this weekend's event at Indianapolis Motor Speedway.
NASCAR's official tire supplier has also made increases at several other tracks this season, said Greg Stucker, Goodyear's director of race tire sales. The greater amounts of downforce, the higher percentage of left-side weight, and the elimination of the ride-height standard in the current vehicle have combined to create a package that "taxes tires more than the previous cars did," Stucker said. That's led Goodyear to revisit its minimum air pressure recommendations at a number of facilities, and Indianapolis this weekend brings the biggest change thus far.
Goodyear's recommendation for the Brickyard is increasing by 4 psi on the left side (to 20 from 16 last season) and 5 psi on the right (to 42 from 37). Teams will use the same right-sides they've utilized since 2012, while changing to a left-side tire that was employed at Dover and Kentucky.
The higher inflation recommendations, though, are "pretty significant," said Stucker, noting that the left-side increase is a jump of 25 percent above what it was a year ago. That stands in contrast to minimum air pressure increases at other tracks, which have typically been about 1 or 2 psi, Stucker added.
"I think it just reinforces how quick Indy is, and the loads that you carry at the end of these big long straightaways," he said. "And the configuration of the car just lends itself to needing a higher inflation than what we've run historically in the past."
The tire setup came from a test at Indianapolis last month involving Greg Biffle, Clint Bowyer, Kyle Busch, Joey Logano, Ryan Newman and Tony Stewart. Yet on-track testing is just part of a process that also involves research on the part of both Goodyear and race teams, all in an effort to help competitors find the right balance between durability and performance.
For every tire combination, Goodyear generates what it calls "force and moment" data, which provides a performance signature of the tire at various loads, pressures and cambers. Goodyear also performs "pressure sweeps" -- durability tests that sweep through a range of pressures and record how long the tire lasts at a certain psi. All the information is shared with teams on a weekly basis through a website that competitors can access.
"Don't just take our word for it," Stucker said. "Trust me, we pick a point for a reason, and it just reinforces what our selection is, and why they are what they are."
Teams also have cars with instrumented wheels that record load data, and that information is relayed to Goodyear, which uses it in its dynamometer to test durability. The minimum air pressure increases at Indianapolis are the result of a process that takes place before every race.
"We're looking at that data and making sure if our pressure recommendations are OK, or if they may need to come up a little bit. At Indy, this is one we identified that we really need to come up both on left sides and right sides, because of the car configuration," Stucker said. "These big, long straightaways, lot of speed, lot of downforce, and just a lot of loads on both sides of the car. So we really felt like the plots indicated to us that we needed to come up."
For teams, it's all about trying to find the sweet spot between performance and durability. Goodyear makes minimum inflation recommendations, distributes test data, and then lets competitors make their choice.
"We understand they're trying to push the envelope," Stucker said. "They're trying to get as much performance out of everything on the race car, and that includes tires. And we understand that. We just want them to know that there are risks you take when you push the envelope with the package. We just want them to know where those risks lie. And ultimately, it's up to them to make that decision. We just want to give them as much information as they can in order for them to make good decisions."