( CNN ) -- During a NASCAR race , drivers do hundreds of laps at speeds of more than 300 kilometers per hour . But the seconds spent during a pit stop -- changing tires and refueling the car -- may be the most crucial moments of any race . Greg Morin is head coach of the 48 pit crew at Hendrick Motorsports , the team that helped one of NASCAR 's most successful drivers , Jimmie Johnson , win six championships . `` It is safe to say that if you do n't have a well performing pit crew that executes well on pit road , you are going to affect the overall outcome of the race in a potentially hugely negative manner , '' says Morin . He adds : `` Our goal is to hit a 12-second pit stop , hit five lug nuts off , five lug nuts on ( on each wheel ) ... get it full of fuel and ship it down pit road . '' Watch the video above to see the Hendrick Motor Sports ' 48 pit crew in action .
NASCAR pit crews are key to a driver 's success . They're the ones who put their bodies on the line for you, and they do it with no safety gear or helmets. Head coach of the 48 pit crew at Hendrick Motorsports explains the art of pit crew .