NASCAR switching tires at fast Michigan track

NASCAR is changing left-side tires for its Sprint Cup race

Sunday at Michigan International Speedway, and will hold an extra

practice session Saturday night.

The change will not affect Saturday qualifying.

NASCAR informed teams of the switch Friday night, after a second

consecutive day of soaring practice speeds at the newly repaved

track. Goodyear says the higher speeds caused increased left-side

tire temperatures, leading the company to change its tire

recommendation.

Drivers routinely exceeded 200 miles per hour in practice, with

Greg Biffle topping out with a lap of over 204 on Friday.