When Tony Kanaan pulls into the pit during the Indy 500 this weekend, almost a dozen people will work together to change his tires, pump in almost 20 gallons of gas, adjust the car to improve his steering, and clean debris from the car’s radiators. And they do it all in 6 seconds.

It’s mind-blowing stuff, so I asked Chris Simmons, chief engineer for Chip Ganassi Racing and a 14-year Indycar veteran, to explain all the stuff that happens. It’s summarized in the video above.