Charlotte, NC(CNN) When race day comes around, Mike Wheeler's biggest concern is the safety of his driver -- NASCAR Sprint Cup star Denny Hamlin.
"We worry about safety more than performance and durability because the driver's safety is number one," says Wheeler. "He is the biggest part of our equation."
Wheeler is pit crew chief for the No.11 Toyota Camry, and he knows all too well the dangers drivers face. He was part of Hamlin's crew three years ago, when Hamlin broke his back in a crash in the Auto Club 400 at California Speedway.
"I remember feeling my back break and I really didn't know if I'd ever race again," Hamlin recalls.
Sitting atop the spotter stand, Chris Lambert acts as Hamlin's second set of eyes, letting him know what's going on around him on the race track. He remembers radioing Hamlin after the crash to ask if he was alright, and not getting a response.
"Finally he was able to catch his breath enough to key the mic and say 'I'm hurt.' That's all we got out of him," says Lambert.
Safety may be the priority, but it's not Wheeler's only consideration; he's also responsible for making strategic calls during the race.
"As crew chief of the 11-man team, it's basically like being the head coach of a football team," he explains.
For Wheeler -- known as "Wheels" -- that means leading the crew during pit stops, making play-by-play calls and coaching Hamlin as he races.
When driving at 200 miles per hour, Hamlin has to have a lot of faith in his crew to keep him safe and get him in and out of the pits, fast.
"Communication is key to having a good team," says Hamlin. "I communicate with them about what the car's doing, the crew chief will take that communication and make adjustments when we come in for a pit stop."
Having spent the past 12 years on the same team, Hamlin and Wheeler are a formidable partnership.
"My biggest fear on race day is making an error that we could have avoided," says Wheeler.
Lambert, Hamlin's spotter, adds another layer to the game plan. "Being with Denny for five years now, I have a good idea of what he's trying to do," says Lambert. "I'm just trying to paint the picture per se of what's going on behind him so he can make the best choice."
Lambert, Wheeler and Hamlin are in radio contact throughout the race. "The communication between the driver, the spotter and the crew chief is very key," explains Hamlin. "You can't have people talking at the same time, so it's like a choreographed radio call of a baseball game."
Wheeler agrees: "Our sport is so busy and so fast paced that having short communication and understanding each other is one of our keys to success."