Speeds down at Michigan after NASCAR tire switch

BROOKLYN, Mich. (AP) -- Greg Biffle posted the fastest speed in an extra Sprint Cup practice session Saturday night - and it was quite a bit slower than his run the previous day.

The Cup cars finally slowed down when NASCAR held the extra practice because of a tire switch for Sunday's race. Biffle's speed was 195.647 mph - he had topped out at over 204 on Friday on the newly repaved surface at Michigan International Speedway.

"The tires are really hard, you can tell," Biffle said. "It is giving up a lot of grip. It is kind of funny, you can hear the tires squealing when you first go out, before it builds temperature, you can feel it sliding on the racetrack. It slows the cars down and as it builds heat it actually starts to gain some of that grip back."

The tire switch was announced Friday night, but it wasn't in effect for qualifying Saturday, when 19 drivers surpassed the 200 mph mark. Teams then scrambled to prepare for Sunday's 400-mile race under different circumstances.

"It kind of threw us for a loop - the engine guys mostly," Biffle said. "They have set amount of miles we can put on the engines and we are a little over this weekend. We are on the throttle so much around here that we are a little concerned with the engine package anyway. This is a little added blood pressure for them all day tomorrow."

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