Crew chief: Front brakes locking up caused wrecks


CONCORD, N.C. -- Issues with front brakes locking up on the Car of Tomorrow caused Jeff Green to wreck Dale Earnhardt Jr. and Greg Biffle last weekend at Richmond International Raceway.

"Jeff Green is a clean racer," Green's crew chief, Harold Holly, said during Tuesday's testing at Lowe's Motor Speedway. "He don't take anybody out. Anybody that says he's doing it intentionally just has a bad attitude."

Holly said he talked to Earnhardt Jr. and left a phone message for Biffle to explain that it wasn't intentional.

"On the restarts my front brakes had a lot more grip and I just locked them up," Green said. "It won't turn with it locked up. If I let off of them I would have gone up the race track anyway."

Holly said this is a problem many teams have experienced with the COT.

"I've seen more front-tire smoke on those cars getting in the corner," he said. "The braking that we have on the front of those cars from a lack of cooling has got us into an ill-balanced mode between the front and rear brakes, especially on the restart.

"We haven't been able to totally get the heat worked out. After you get into the run the balance is good. They shouldn't be doing that, so there is an issue with the car somewhere."

Holly said the problem is only at the shorter tracks such as Richmond, Martinsville and Bristol. He said it wasn't a problem at Phoenix, a mile track where the speeds are much higher and brakes aren't used as much.

Jimmie Johnson, who has won a series-high four races this season, said even he has had issues.

"Jeff Green's deal is highly talked about right now, and in his defense we've seen a lot of left fronts lock up," he said. "All the cars do that. You just can't drive into the corner that hard.

"In the past if the car wouldn't turn you could use the brakes and get aggressive with the vehicle. Now if you do that it locks the tire up. There is no way the car is going to turn. It's going to go straight and you're going to have contact with somebody."

Holly said there's several ways to fix the problem, which has been created because the tires travel -- the distance the tire moves into the chassis -- only half as much as the old car to keep from damaging the front-end splitter.

"We never had the limited travel that we have on these cars," he said. "The old car would travel five to six inches. This is less than three because of that splitter height.

"You get that splitter on the ground and knock it off and you lose everything on the front and you're done."

That's why many teams are asking NASCAR to do something to improve front-end downforce.

"I'd definitely like to see them put more front downforce in the car, and change really the body characteristic," Denny Hamlin said. "Maybe let them travel a little bit more than what we have now.

"That way we get a more comfortable feel. And when we're more comfortable we're able to race better and that will translate into better racing."

David Newton covers motorsports for ESPN.com.