BROOKLYN, Mich. -- Speeds from Saturday's practice slowed by five to six miles per hour with the new left-side tires NASCAR mandated for Sunday's Sprint Cup race at Michigan International Speedway.
NASCAR and Goodyear called for the change that left teams scrambling late Friday when tires began blistering because of excessive heat buildup from high speeds created by the newly-repaved track.
Greg Biffle posted Saturday's top lap at 195.647 mph, down from the 199.093 mph he posted in race trim on Friday. In qualifying trim before the tire change, Biffle posted a fast lap of 204.708 mph.
"The tires are really hard, you can tell," Biffle said after the emergency practice. "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 track.
"It slows the cars down and as it builds heat, it actually starts to gain some of that grip back."
NASCAR made the move to avoid blowouts and another catastrophe such as the one at Indianapolis in 2008, when a competition caution was called every 12 laps because tires were blistering and blowing.
The consensus after Saturday's practice, despite slower speeds and ill-handling cars, was the switch was necessary even though several top drivers had no issues with blistering on Friday.
"I am forecasting we will be just fine," Carl Edwards said after posting the third fastest lap at 194.138 mph.
But the swap did pose problems for crew chiefs and engineers scrambling to figure out setups and adjustments for the new tire. Most teams were limited with the number of laps they could put on their engines because they were near the maximum for a weekend.
Fourteen drivers ran less than 25 laps.
"We'll try to get a handle on it as quick as we can, just like everybody is going to do," said Tony Gibson, the crew chief for Ryan Newman. "Goodyear had to do it. NASCAR had to do it. We're all in the same game. We don't want to have issues on Sunday."
The new tire, a much harder compound, was used at Charlotte Motor Speedway in 2006 and 2007 after a repave. As expected, it gave drivers less grip and made the cars harder to handle.
"That's one thing we said last night; there's probably going to be a lot of wrecks," said Rodney Childers, the crew chief for Mark Martin. "You're going to have a lot of wrecks if people are blowing tires every 15 laps, too.
"A lot of people at home are watching on TV. It's just not good for people to sit there and watch tires blow all day long."
Dale Earnhardt Jr. said the tire drove "like it's six years old."
"It's really slick," he added after posting a best lap of 192.109 mph. "Our engine guys don't like to run over a certain number of laps. I'd like to practice more, but I can't.
"My car ain't as good as I want it to be, but I can't run more laps. This ain't cool."
Jimmie Johnson, who had the second best lap at 194.295, tweeted: "We found a great balance on these lower grip left side tires and it appears the blistering is under control now. I'm pumped for the race!"
NASCAR had a public-relations disaster at Indianapolis. Officials hope they avoided one with this decision though it put more stress on teams preparing for the race.
"It's a big decision," NASCAR vice president of competition Robin Pemberton said. "We have to side with Goodyear. They develop the tire and are responsible for building a safe tire and competitive tire. They do a lot of tire testing. It's not taken lightly when something like this occurs. You have to respect people who have all the knowledge."
Not having issues on Sunday was the bottom line.
But Howard Comstock of Dodge SRT Motorsports Engineering said engine durability and handling could still prove to be problematic.
"It's disappointing that after nine hours of track time, we have to change the left-side tire and we'll only get an hour to adapt to it," he said. "Figuring out that new left-side tire is going to be a big key."
"After everything that happened at Indy, I'm proud Goodyear and NASCAR had a backup plan," he said.
Harvick also anticipated the cars won't be quite as tough to handle on the new tire as they were at Charlotte.
"The groove already is from the bottom to the second grain," he said. "You've already got options. When we went to Charlotte for the first time we were pinned to the bottom and had a lot more load on the tires."
The biggest issue could come from drivers who did not like the 2006-07 tire used at Charlotte because it made the car so tough to drive.
"The disease they had was terminal," Roush said. "When you're desperate, you'll reach for measures that in sobering times you wouldn't consider."
Said Gibson: "I don't think it will be as much fun to drive for anybody. I think it's going to be slipping and sliding. The balance is going to be way different than yesterday. You're going to have to build a lot of adjustability in your car for Sunday because you don't have a lot of time on it."
Denny Hamlin expressed his concern on Twitter before qualifying.
"My excitement level for this new left side tire is pegged at 10 out of 100," he wrote.
The new tires arrived at Michigan shortly after noon on Saturday after being delivered from North Carolina. There wasn't enough time physically to get them here in time for an earlier test, so tires used the past two days during a test and practice were used for qualifying.
Even when the tires arrived there were issues. Because the trucks couldn't cross the track during Cup qualifying, the tires had to be unloaded and brought in on pickup trucks through the tunnel.
Despite all the inconveniences, most agreed the change had to be made. Goodyear's Greg Stucker said at least a quarter of the field had issues with left-side tires blistering.
Goodyear attempted to correct that problem by suggesting teams scuff the tires -- putting some wear on them to make them harder and more durable -- but that didn't fix it for everyone.
"(Friday) we made some changes to tighten the car up and slow it down, which it did," Childers said. "We ran a long run on stickers and tore up three out of four tires. Then we made a long run on scuffs and tore up three out of four tires.
"All in all, it wasn't going to be good for anybody."
Because most teams already scuffed right-side tires, that could present an issue mixing with new left-side tires.
"But it'll be the same for everybody across the board," Gibson said "Whoever adjusts to it best is going to be good. I still think you'll see the same guys running up front that you do every week."
Childers said he expects race speeds to max out at around 198 mph, about seven miles slower than teams were running in qualifying trim on Friday. He said that should put less stress and heat on the right-side tires that blistered on Martin's car.
"In one way, it kind of stinks for everybody that we're having to do this," Childers said. "On the other hand, it's good for Goodyear and NASCAR to stand up and say we've got to do something here. We can't pit every 15 laps and put on a stinky show. It's tough. We'll all get through it."