What makes a crew chief one of NASCAR's best?
Is it his ability to keep a driver cool, calm and collected over the course of a 500-mile race?
Is it his knack for finding a loophole in the rules that provides his car an advantage, or for developing a strategy that conserves more fuel than the rest of the pack?
Is it the way he leads his team, motivating everyone to perform at the highest level every weekend until they win a Sprint Cup?
Of course it's not a single factor—it's a combination of all of these that will take a crew chief to the top. Some get lucky by landing with a mercurial driving talent, but many are an indispensable part of the team's success, race managers without whom their driver would be considerably lower in the standings.
These 10 crew chiefs fall into the latter category.
Harrison is a rising star in NASCAR's crew chief ranks who may be in for a role at a bigger team if Phoenix Racing closes down after Indianapolis in July as reported. Over the past two years, he's taken an underfunded team and made it a viable competitor for decent finishes with a revolving door of drivers, from Kurt Busch to Regan Smith to Bobby Labonte last week at Michigan.
He's been patient enough to keep Busch mostly in line (or at least better than Penske Racing did), good enough at the restrictor plate tracks to get Smith in the top 10 twice this year and collected enough to keep his head on straight through the firestorm that has been his team's unsecured future. Harrison is going to land a big-time job soon enough, and there's a good chance that he will flourish in it.
Puccia has gone from a crew chief who struggled for results in the Camping World Truck Series (only one career win there) and Nationwide (none there) to one of the position's rising stars in Sprint Cup.
Since being paired with Greg Biffle, Puccia has led the No. 16 team to three wins, 32 top-10s and six poles in 69 starts, for an average finish of 12.9. His ability to turn around a team that had lost its verve with Greg Erwin atop the box suggests that he may be around for a while.
Letarte has been atop a Hendrick Motorsports pit box since 2005, when he inherited the helm of the No. 24 team from Robbie Loomis. Letarte and Jeff Gordon won six races in 2007 on the way to a runner-up finish in the standings, producing an average finish of 7.5 in 32 races (Letarte was suspended for four).
Now, he works with Dale Earnhardt Jr., having returned the No. 88 to Chase contention after two sub-20th-place seasons. Letarte helped Earnhardt Jr. break a four-year winless drought at Michigan last year, leading him to a career-best average finish of 10.9.
After a disastrous start to the 2005 Cup season atop the pit box of the late Jason Leffler, Rogers resurfaced in the then-Busch Series in 2006 with Denny Hamlin and led that team to a fourth-place finish in points. Working with drivers of various skill levels, Rogers spent four years making Joe Gibbs Racing into the team to beat in Nationwide before earning another promotion back to Cup with Kyle Busch.
Since then, Rogers has led Busch to 10 victories, two Chase appearances and seven poles, as well as nine top-10s in 15 starts this year. The No. 18 team still has some unrealized potential, but Rogers has been keeping the team up front.
Gustafson's Cup career began with Kyle Busch in 2005, and save for one off year with Casey Mears, he's been consistently helping drivers make it to the Chase. With Mark Martin in 2009, Gustafson led the No. 5 team to five victories and a runner-up championship finish to teammate Jimmie Johnson.
Now, he runs the No. 24 team for Jeff Gordon, making sure that the four-time champion has at least the opportunity to earn a fifth. Though this season has seen its ups and downs, the relationship has produced five victories and 40 top-10s in 87 starts so far.
A former Chad Knaus disciple who won the 2006 Daytona 500 in his crew chief debut while Knaus was suspended, Grubb has always been a reliable leader who gets maximum performance out of his drivers. He led Casey Mears to the only victory of his career in 2007 and brought Tony Stewart to the 2011 title despite knowing he would be terminated after the season.
Grubb landed on his feet at Joe Gibbs Racing, where he brought Denny Hamlin back from a subpar 2011 by scoring five victories and a sixth-place championship finish. This year will be his toughest yet, as he tries to get Hamlin into the Chase despite an injury that caused him to miss four races.
There's a reason why Francis keeps getting hired wherever Kasey Kahne goes: The rapport between the two is phenomenal. Their first season together, in 2006, produced six victories and an eighth-place finish in the Chase, and they've been nearly inseparable ever since.
Francis has fit right in at Hendrick Motorsports, where a strong crew chief makes all the difference. Though Kahne fell out of the top 30 in points last year, Francis helped bring the No. 5 team back to Chase contention, eventually finishing fourth in points.
Between winning the 1988 Daytona 500 with Bobby Allison and leading Mark Martin to a career-best seven victories in 1998, Fennig languished with some mediocre drivers as a part of Stavola Brothers Racing and later with Allison's own team. But since joining Roush Racing in 1997, he's become one of the top names in the business, leading nearly every driver he's worked with to the front.
Fennig nearly put David Ragan in the Chase in 2008, the driver's second year in Cup. He took 14 victories apiece with Martin and Kurt Busch, also leading Busch to the 2004 Cup title. Last year, he won the Daytona 500 again with Matt Kenseth before leading Carl Edwards to second in points through 15 races this year.
Knaus has, for the past decade, been the gold standard of Sprint Cup crew chiefs, leading Jimmie Johnson to 61 victories since joining Hendrick Motorsports in 2002. His star began rising after he and Melling Racing built monster super speedway cars for Stacy Compton in 2001 (Compton's average start at Daytona and Talladega combined was 1.8 that season).
The rest is history—literally, most of Knaus' career has been about making history. The No. 48 team won five consecutive championships with him atop the pit box from 2006-2010, and Johnson's status as the greatest driver of his era is, in many ways, thanks to the innovations developed by his crew chief.
The ex-driver turned pit boss who heads the No. 2 team may very well have inherited the title of Sprint Cup's best crew chief from Knaus after last season's championship run. After leading Brad Keselowski to a Nationwide title in 2010, scoring six victories and 26 top-fives in 35 starts, he was immediately promoted to Penske Racing's Cup team, again with Keselowski.
Since then, they've teamed for eight victories, a fifth-place finish in 2011 points and a championship last year after outdueling Jimmie Johnson and Chad Knaus. Wolfe has the No. 2 team in steady Chase contention once again this year, with sights firmly locked on a second title.
And while Knaus and the No. 48 team have been dominating so far, everything changes come the Chase—where Wolfe has proven that he can beat Knaus at his own game.
For more from Christopher Leone, follow @christopherlion on Twitter.