Preheat the smoker to 250℉. I like to use oak for a classic smoke flavor, hickory for a bolder taste, or cherry for a milder smoke and deep, dark bark.
Trim off the fat cap, silverskin, and any thin pieces of meat, if they have not already been removed by your butcher.
In a small bowl, whisk together the black pepper, salt, onion powder, paprika, and cumin. Season all sides of the meat, gently pressing the spice mixture into the surface.
Place the tri-tip directly on the smoker grates. Close the lid and smoke for about 1½ - 2 hours, or until the internal temperature is 5 to 10°F below your desired doneness.
Increase the smoker temperature to 500°F and cook until the meat reaches your desired doneness: 115 to 120°F for rare, 125 to 130°F for medium rare, 135 to 140°F for medium, 145 to 150°F for medium well, or 150 to 155°F for well done.
Remove the roast from the smoker, tent with foil, and let it rest for 15 minutes. Slice against the grain before serving.