Grilling Tri Tip takes between 1 hour and 40 minutes to 1 hour and 45 minutes depending on how well done you like your Tri Tip.
I like my Tri Tip to be well cooked which it is when I grill the Tri Tip for 1 hour and 45 minutes.
When cooking the Tri Tip on the grill place it on the grill and then after 10 to 15 minutes turn it over and let it cook for another 15 minutes and turn it over again until it's done.
The internal temperature of Tri Tip when grilled should be 140 F for medium rare and 155 to 165 for well done.
I cook my Tri Tip until the internal temperature reaches at least 160 F which means it's well done enough for me.