DARLINGTON, S.C.—During a two-day Goodyear tire test this week at Michigan International Speedway, Greg Biffle reported straightaway speeds of as much as 220 mph.
That’s about 7 mph faster than NASCAR Sprint Cup Series drivers ran during practice last year, but, surprisingly, Biffle said the increased pace didn’t affect the way he had to run the corners.
“It really didn’t, believe it or not,” Biffle told the NASCAR Wire Service before Friday’s opening Sprint Cup practice at Darlington Raceway. “It makes it a little more like a qualifying lap more than anything. The corner was about the same. Let’s keep in mind that it was 40-something degrees with a track temp of 66.
“So it was cold temperatures with high grip and they were testing tires that had more grip. They put a tire on the car that we’re not going to race that went that fast. So on the standard tire, I think the (speed) was down maybe three or four mph from that.”
Biffle expects Goodyear to bring more durable left-side tires to the recently repaved two-mile track.
“I’m not so worried about those end-of-the-straightaway speeds,” he said. “We slow down a bit in the corners—that’s the thing. When they get sustained that high, it makes it harder to pass and harder to race. Goodyear is trying to come up with a little more reliable tire, and I think they’ve done that.
“I’m thinking they are going with the dual zone tread possibly, or at least that is what they were leaning toward (for the right-side tires). We’ll see what they come up with after all the data. I think that’s a better tire, because it puts a little margin in the right front. They don’t want to blow a right front at that track.”