Begin by trimming any excess fat from the tri-tip roast. You want a nice, even layer of fat that will render down during cooking.
In a mixing bowl, combine olive oil, garlic powder, onion powder, paprika, salt, black pepper, oregano, and thyme.
Rub this mixture evenly over the tri-tip, ensuring every inch is covered. For the best flavor, let the tri-tip marinate for 1-2 hours in the refrigerator. However, if you're short on time, you can cook it immediately.
If you're using a charcoal grill, prepare for both direct and indirect heat. For a gas grill, preheat to medium-high heat. Ensure the grill is clean and well-oiled to prevent sticking.
Place the tri-tip on the grill over direct heat. Sear each side for 5-7 minutes until a nice crust forms.
Move the tri-tip to indirect heat, cover the grill, and cook for another 20-30 minutes, flipping occasionally.
Use a meat thermometer to check the internal temperature. For medium-rare, aim for 130°F (54°C); for medium, go for 140°F (60°C).
Once the tri-tip reaches your desired doneness, remove it from the grill and wrap it loosely in aluminum foil. Let it rest for 10 minutes to allow the juices to redistribute.
Unwrap the tri-tip and place it on a cutting board. Slice against the grain for the most tender bites. Serve with your favorite sides and enjoy!