How long do you cook a 2.17lb tri-tip on the barbecue?

For a 2.17 lb tri-tip, you should cook it on the barbecue for about 25 to 30 minutes per pound at medium-high heat, turning it occasionally. This typically results in a total cooking time of approximately 50 to 65 minutes for medium-rare doneness. Use a meat thermometer to check for an internal temperature of 130-135°F for medium-rare. Let it rest for about 10 minutes before slicing to retain the juices.