DAYTONA BEACH, Fla. —Jimmie Johnson knows it's all going to end. Everything will be different. He'll have to start over.
No, not the streak of four consecutive championships.
In the middle of one of the most dominant periods in modern sports history, Johnson, in his ninth full season, stares through the window of his Sprint Cup career and sees a time when Chad Knaus no longer will be his crew chief.
There will be another guy on the radio, another guy making the crucial pit calls.
The question is, how long can he delay it?
"I keep pushing him at numbers and he'll throw around numbers: 'Five more years,' " Johnson said. "And I go, 'Five more years? Dude, I got 10 more in me. I'm not driving anyone else's cars.'
"I keep pushing him along, but at some point he's going to say he can't do it anymore."
In five years, Johnson will be 39, still in a stock car driver's prime. Knaus will be pushing 44 and likely doing something else. The where and with whom is the nebulous part.
Knaus is vigilance and excellence combined, the only NASCAR crew chief to win four consecutive championships. Paired with Johnson, the only driver to win four straight titles at NASCAR's highest level, it's a seemingly unbeatable combination.
Johnson without Knaus? It's a disconcerting thought for a driver who has established a dynasty and won 47 races, most among active entering today's Sprint Cup season-opening Daytona 500.
Johnson knows the brain of his crew chief is almost constantly working to make the No.?48 Chevrolet go faster, its crew perform better.
But Johnson also acknowledges the almost-religious dedication pulls down harder on Knaus each year.
After hoisting the 2009 championship trophy during November, Johnson and his wife Chandra set about preparing their home and lives for the birth of their first child.
Knaus, meanwhile, was on the Hendrick Motorsports campus on the 2010 season within 48 hours.
"He doesn't get the month and half off I do. He doesn't get Mondays off like I do," Johnson said. "My other days, some are busy some are light, but he's seven days a week grinding it out."
Burnout, ultimately, is the price, Johnson said.
"I think that crew chiefs live in dog years, for sure," Johnson said. "There's no way he doesn't hit his threshold before I do. I hope that he is always a part of the 48 team.... I want to work with him as long as he is willing to work."
Knowing the goal-oriented nature of his collaborator and friend, Johnson dangles carrots. For Knaus, there remains the Daytona 500. He was ejected from Daytona after Johnson's car failed a 2006 post-qualifying inspection, but Johnson went on to win with Darian Grubb as a fill-in.
Johnson and Knaus have been intertwined since Knaus returned to Hendrick Motorsports in 2002.
They still seem legitimately excited over the most mundane of accomplishments, peeved over bad days that generally aren't that bad.
They've had their spats, but they've come to understand they are good for each other.
"We've come to a place where we're real comfortable with each other," Knaus said. "It's sometimes better to have the devil you know than the devil you don't. We really work well with each other. Why mess with that?"
Still, Knaus acknowledges his longevity as a crew chief will not equal Johnson's as a driver.
"I don't think we're a boxed set," Knaus said. "Will I at some point work with another driver? Yeah, more than likely. Will he work with another crew chief? Yeah, more than likely.
"Let's be honest, he's younger than I am. He's probably going to drive longer than I necessarily want to be a crew chief."
There is value in what they've built.
Kirk Shelmerdine's decade with Dale Earnhardt yielded 46 victories and four championships during their final six years together.
Tony Stewart and Greg Zipadelli won 33 races and two titles before Stewart left last season to drive for his own team.
Jeff Gordon and Ray Evernham won 47 races and three titles before the crew chief left in 1999 to build his own team.
Matt Kenseth and Robbie Reiser raced against, then worked with each other back in Wisconsin and in the Nationwide Series before being paired at Roush Fenway Racing. They won the 2003 series title before Reiser was named general manager in 2007.
"I do know when you look at combinations of drivers and crew chiefs, there are some that work really good: Jeff and Ray, me and Chad, Tony and Zippy, Matt and Robbie Reiser," Johnson said. "History probably shows you don't do better when you switch it up."
Of the more compelling images revealed in Johnson's just-released HBO documentary is the juxtaposition of Johnson's relationship with his wife, and Knaus cooking pasta for one and dining with his laptop and the evening news in a massive, desolate kitchen.
Knaus, whose girlfriend lives in Chicago, said he considers the Johnsons family and openly gushes over the prospect of playing with their child.
He waited to address the media Thursday after Johnson won his 150-mile qualifying race by making funny faces at driver Max Papis' infant.
While basking in his fourth straight title at Homestead, Fla., last fall, Knaus talked about his future.
"I hope that 10 years from now, when I'm sitting on my patio retired with my son or daughter or my wife or whatever is going on there, I can sit back and reflect and look at photographs," he said.
Johnson, laughing, replied: "I have three questions. Retired, son and daughter? You have a lot to do in 10 years, buddy."
"It's all coming, man," Knaus said. "It's all coming."
For it to come, Knaus might have to split one of history's great stock-car pairings.
"It is unfortunate and that is the reality of it. And that's a choice you make," said Evernham, a mentor for Knaus. "I was married and had a family and largely because of the way I worked, I do not have a wife anymore and I am not close with a lot of members of my family. But look at anybody that achieves at a high level: sports, medicine, whatever. Sadly, family and friends are often the things that suffer."
Gordon's current crew chief, Steve Letarte, 30, fights that reality every day. His family, which includes 4- and 6-year-old children, serves as a buffer from a job that can consume every waking hour. After making race calls for Gordon, then flying home in a private plane, he is thankful for his laundry and dish chores.
He has vowed to move on by the time he's 40.
"I don't think if a guy's single, his career is any longer," Letarte said. "He burns out for different reasons. I think having a family is an advantage because it allows me to have something outside of this to kind of let me live and breathe.
"If this is all I had in my life, the world would close in. I don't know if I could get up to do it the next year."
That hasn't been a problem for Knaus. Yet.
"We're a long way from being done with the 48 car," Knaus insists, but acknowledges "one day I'm going to wake up and go, 'You know I'm tired. I don't want to do this anymore.'?"
Ultimately, Johnson and Knaus seem to understand their dynasty, if not their working relationship, comes with an expiration date.
"I think you keep an eye on that," Evernham said, "but I don't think you think about it while you're doing it. I think everyone realizes there is a cycle. You ride that cycle as long as you can."
"We have something very special," he said. "So with that in mind, I'm like, 'Dude, you're not done until I'm done. You're riding this thing out.'?"