Keselowski, who was part of the April tire test that helped determine the tire setup for Cup and Xfinity teams, said on Twitter, “Our team (and several others) tested multiple tire compounds and recommended every one of them but this one. In no way do I wanna be associated with this decision.”
Compared to what was run at Michigan last year, the new left-side tire features an updated construction that brings it into line with what is run at other speedways and a new compound to introduce more wear. The new right-side tire is a single tread compound tire (last year was a multi-zone tread tire) with a new compound that will introduce more wear and run cooler.
Greg Stucker, Goodyear’s director of racing, appeared on SiriusXM NASCAR Radio’s “Tradin’ Paint” to clarify what package NASCAR will be using at the 2-mile track.
“Brad did not run this exact combination that we’re racing at Michigan,” Stucker said. “He ran the right-side compound by itself with the 2017 compound, the left-side compound. The left-side compound is meant to give a little bit more grip that perhaps we’re taking away with the right side. I hear him. He felt like he was down on grip with that particular run. But he didn’t run the combination as we’re going to have it this weekend at Michigan. I’m hoping once he gets there this weekend he’ll feel that the right side that we ran, combined with that left side, makes for a raceable package. Because all the other guys who ran the right side felt it was at least as good as the tire we raced in 2017 and perhaps even a little bit better.”
Stucker added: “Brad’s involved in a lot of our testing through the Penske organization. He provides a lot of good feedback. He really is a good tester because he’s got a good feel. He’s got good ideas and it is important for us during a tire test to get that feedback from the drivers. It’s a big piece. But that’s not the only thing we look at. We also look at the date that we generate, the data that the team’s generate and you rely on good engineering judgement as well to pull all that together to make the right decision.”
Stucker said the goal of the tire test in April was not “to go faster,” saying the track is the fastest on the circuit, with tops speeds reaching 212 mph and 175 mph in the corners.
“What we were really trying to do is create some differentiation between the top speed and let’s say the mid-corner speed,” Stucker said. “If you find the right balance between the on-throttle and off-throttle time, that’s what creates the opportunity for good racing. If everybody’s just on the throttle hard with very little off-throttle time, it kind of equates the field.
“We’ve been working with NASCAR trying to figure out, ‘What can we do at Michigan to try to create a little bit more differentiation between the on-throttle and off-throttle time?’ Then that kind of puts it in the hand of the team to try to manage that. One way we can do that is through tire wear. As tires wears they tend to lose some grip, which means you can’t run the corners as hard, so you have to manage the car a little bit more at that time. That hopefully creates different opportunities for different guys. That’s why you see guys start searching around for different grooves, move up the race track trying to find some grip … It tends to lead to good racing.”