1. Combine the spices and salt, and rub it generously on the meat surfaces. Be sure to work it on with your fingers gently. Once done, let the Tri-Tip sit at room temperature for 45 minutes.
2. Turn on the burners of one side of the grill and set to high heat. And when the grill is hot, sear the Tri-Tip over direct heat on all its sides. You’ll want a nicely browned surface on every part of the meat.
3. Once it’s seared, move the roast to the unlit side of the grill and cover the lid. Leave it to Slow-Cook until the internal temperature reaches 140F. You’ll need to use a meat thermometer for this purpose. And once it’s attained, set the roast down and tent it loosely with foil.
4. Allow the Tri-Tip to sit for 10 to 15 minutes, so it rests. Also, the carryover cooking will raise the internal temperature to the approved 145F. Once rested, slice the roast thinly and against the grain to serve.

Another method of this recipe can also be found in this video.