I always get my Tri Tips from a local Butcher that knows what they are doing. Large grocery stores do not typically keep Tri Tip steaks. I usually ask for the largest Tri Tip they have (~5 pounds)
You will want to trim off the excess fat.
After the trimming, I salt the Tri Tip for 20 minutes. This helps pull the moisture to the surface. The salt then dissolves into this moisture and re-enters the meat. This creates a brine effect. It will make the Tri Tip have extra flavor and increase juiciness.
After the 20 minutes, quickly rinse the Tri Tip. Pat dry and get your favorite beef rub. Make your own or use your favorite store bought one!
I apply my rub generously. My rub does not have too much salt in it. I recommend using a little more caution with the rub, if it has generous amounts of salt in it (as we salted the Tri-Tip prior to applying the rub). If salt is minimal, you can go heavy on the rub.
While your Tri Tip sits with the rub, fire up the Traeger and set it to 200F.
Once the Traeger is at temp, I put the Tri Tip in for 50 mins. This seems to be enough time to get a smokey flavor into the Tri Tip.
After the 50 mins, I remove the Tri Tip from the Traeger and wrap in foil. I crank up the Traeger to 500F. The Tri-Tip remains off the grill (wrapped in foil) while the Traeger's heat rises.
Once the Traeger is at 500F, unwrap the Tri-Tip and put it back on the grill for some final searing (Keep the foil for later).
Sear each side roughly 4 minutes each until you reach an internal temp of 130F.
Once you hit the temp, remove the Tri Tip and wrap into the foil again; letting the Tri Tip rest for 15-20 minutes. The rest is crucial because the juices will be reabsorbed back into the center of the Tri Tip. If you cut into the Trip Tip too early, you will lose a lot of the juices.
Once the resting period is over, it is time to cut the Tri Tip. It’s important you do this right. Cut the Tri Tip against the grain of the meat. This will create a more tender steak. Also cut it the width of a pencil ahead. Essentially the same width as brisket.