DARLINGTON, S.C. - Jimmie Johnson and his crew chief Chad Knaus worked hard Thursday night to come up with some improvements for their car and for two laps during Friday's practice, Johnson had one of the fastest cars.
One lap later, however, his No. 48 Chevrolet hit hard into the Turn 1 wall, forcing Johnson's team to go to a backup car prior to qualifying.
"We're still very optimistic about the gains we've made and I'm still trying to understand why we lost it," Johnson said.
"I lost it early on the straightaway before the corner, so something happened on the straightaway."
The problems weren't over for Johnson, however. In the final practice session, Johnson spun and snagged the inside wall, knocking the front splitter off the car.
Paul Menard, Robby Gordon and Reed Sorenson also did significant damage to their cars in the final practice session.