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.