Place the tri-tip in a baking dish or sheet pan. Coat the tri-tip on all sides with the rub. Cover with plastic wrap and refrigerate for at least 4 hours or up to 24 hours.
Place a large foil pan on top of the Flavorizer bars, on the left side of the grill, below the cooking grate. Fill it halfway with room temperature water. Prepare the grill for cooking over high heat (500°F).
In a small bowl whisk the sauce ingredients. Refrigerate until ready to serve.
Combine peppers and onion in a bowl and toss with oil.
Remove tri-tip from the refrigerator 30 minutes before grilling. For an accurate reading, ensure that the probe tip is inserted 2 inches into the thickest part of the tri-tip.
Sear the tri-tip on the right side of the grill, over high heat (500°F), with the lid closed, for 10 to 12 minutes, flipping once.
Adjust the grill temperature to medium heat (400°F). Place the tri-tip on the left side of the grill, above the foil pan, and continue cooking over medium heat (400°F), with the lid closed. Cook until the thickest part of the roast registers your preferred doneness.
While the tri-tip is roasting, place the Deluxe Grilling Pan on the right side of the grill and preheat for 10 minutes.
Grill the pepper and onion mixture over medium heat (400°F) for 8 to 10 minutes, stirring occasionally.
Remove the tri-tip from the grill, and rest at room temperature, indoors, for 20 minutes. Remove the pepper and onion mixture when they are tender and season to taste.
While the tri-tip is resting, grill the tortillas over medium heat (400°F), for 1 to 2 minutes, flipping once.
Cut the roast across the grain into thin slices, and then cut the slices into bite size strips. To identify which direction the grain of the meat is running, look for the parallel lines of muscle fiber running down the meat, and cut perpendicular to them.
Build the tacos by layering the adobo sauce on the tortilla first, followed by onions, peppers, tri-tip slices, smashed avocado, radishes, cilantro, and fresh lime. Serve warm.
