KANSAS CITY, Kan. (AP) -- Chase leader Matt Kenseth could be forgiven for a relatively sour opinion of the tire that Goodyear brought to Kansas Speedway this weekend.
It's not that he dislikes the ''multi-zone tread'' that made its debut Sept. 1 at Atlanta. It's just that the defending race winner at Kansas would have been happier with the status quo.
''I would have rather left everything alone, for us, especially after today,'' Kenseth said after Thursday's tire test. ''Today was a struggle, and any time something is new and you struggle where you've had success, you kind of wish you could go back.''
That's not happening, though, so Kenseth's crew will have to figure things out in a hurry.
It's rare that NASCAR changes tires between spring and fall races on the same track, but vice president of competition Robin Pemberton said it made sense at repaved Kansas Speedway.
The glassy smooth surface of the newly pave track resulted in trouble with grip during the spring race, leaving Goodyear trying to come up with a solution. Four teams tried out the multi-zone tread earlier this summer, and the rest of the field got its chance to test Thursday.
''I thought the track had good grip,'' said Jeff Gordon, who's tied with Kevin Harvick for fourth in the Chase. ''It lost a little bit probably due to track temp toward the end of the day. It would help to lay some rubber down but I'm not so sure this tire is going to do that.''
Goodyear has used multi-zone treads on passenger cars for years, but only recently brought the technology to NASCAR. The idea is to meld two different compounds onto a single tire, one of them offering better traction and the other better endurance.
So in the case of the tires the Sprint Cup will be running this weekend, the outer portion of the tire features a more tractive tread for better grip and handling. The inside shoulder offers a firmer compound that helps manage wear for better durability.
''Typically we don't have a midseason code changes on tires between the spring and fall, but this is a unique set of circumstances with the repave,'' Pemberton said. ''Goodyear has gone above and beyond to develop tires and bring the best stuff they can to the racetrack. But it's a test we didn't have planned on the books to do.''
Jimmie Johnson was the fastest of 38 drivers who tested the new tires during a 3-hour session that was delayed by rain. Johnson, who is second in the Chase, turned a fast lap of 182.648 mph near the end of the test. He was followed by Carl Edwards and Kurt Busch on the speed chart.
Sprint Cup Series director John Darby said that the best news out of the tire test was that there was very little news. Nobody had much trouble with grip and early opinions were positive.
''One of the exciting parts about having it here at Kansas is because this is a recently paved track, it's very smooth,'' Darby said. ''We ran the zone tread at Atlanta without any technical issues or failures and had a good race, but that's on a very aggressive, coarse track surface, one that is known to chew up tires. We had that example, and this is the other end of the spectrum.''
Edwards and Gordon both endorsed the tire, even if Kenseth preferred it had stayed the same.
''At the beginning of the day, the tire had a ton more grip, and as it rubbered up it got a lot more slick,'' Edwards said. ''But you could actually drive it. It's not a knife-edge, hard to drive. So I believe you'll see two- and three-wide racing this weekend.''