NColoradoAG said:
Season with salt, pepper, and garlic powder. Smoke indirect to 120 and pull. Get grill ripping hot. Grill, flipping often, to get a crust and desired temperature. Let rest 10 minutes. Slice pencil width against grain. Grain runs two ways in a tri tip so you have to cut it into two pieces to get it right.
Serve with pinquito (or cranberry, or pinto) beans, salad with vinaigrette, and grilled bread.
I went to Jr High and High School in Santa Maria. It took me a full two years to realize that when someone had a bbq it meant tri-tip and grilled chicken--it never brisket, ribs, or even grilled burgers.
I am not an expert, but I know a few. What he said is pretty spot on--those are even the traditional beans. And the salad was usually ranch. Grill a plain loaf of french bread and dip in a pan of melted butter with a little of your seasoning mixed in. I would add parsley to that seasoning mix and maybe a pinch of sugar (but only if you season the night before--it will help tenderize the meat.
But as he said make sure you cut against the grain or it will not be good.You don't really have to have a grill that raises and lowers, that is mainly because Santa Maria gets super windy. So they use a deep grill and lower the grate into it. I don't smoke mine, just cook it fast (think steak, not brisket) over red oak (if available). While it's cooking add some linguica sausage, roasted poblano/anaheim peppers, and tortillas to the grill for a snack.
Do not serve with bbq sauce, we used a good salsa or pico.
My whole family uses this to season them (works well on chicken too):
https://susieqbrand.com/