Stir all ingredients together in a bowl& rub over the roast.
If you do this ahead of time, cover& refrigerate up to 24 hours.
Heat 1 burner of a double burner BBQ or the 2 outside burners of a 3 burner BBQ to medium (250F- 300F).
Place roast ongreased grill over unlit burner; close lid& grill, adjusting heat if necessary to maintain temperature, for 2 hours or until meat thermometer inserted in the center registers 140F (for rare) or 150F for medium-rare.
Transfer to cutting board, tent with foil& let rest for 10 minutes before carving.