I don't know if other parts of the country regularly get tri-tip roasts in their market but it is a favorite cut of beef for me to grill. It has a nice beefy flavor and it is tender and juicy. It's on sale at our local market so I had to buy a couple of roasts; one for dinner and one for the freezer.
The bottom side, not shown, has a fat cap layer that I trim to about 1/8"
I rub it in oil and then give it a dusting of my home-made rub. "Mikey's Don't Rub Me The Wrong Way Rub"
I start off with a hot grill to sear both sides.
4 minutes each side
I then finish cooking it on the raised warmer rack using indirect heat. I put an aluminum tray with 1/2" of water in it directly beneath the roast to catch the drippings for making gravy.
After about 60 minutes the center of the roast reaches a temperature of about 140 and it is done. I then let it rest for 30 minutes.
The center is medium rare....just the way I like it. Because the ends are a thinner cut they will be well done, but still pretty tender and then as you move to the center of the roast you have medium and then medium rare in the center. Trip-tip roasts should be cut as above because the direction of the grain in the meat changes in the middle. You want to slice the beef against the grain for the most tender slices. I like mine plain; the Fetching One likes her's with horsey sauce and our son likes his with gravy.....
It's good eats...