In large resealable food-storage plastic bag, mix coffee, brown sugar, salt, black pepper, red pepper and garlic. Add steaks; seal bag and turn to coat. Refrigerate to marinate 8 hours, turning occasionally.
Heat gas or charcoal grill. Remove steaks from marinade, discarding marinade. Carefully brush oil on grill rack. Place steaks on grill over medium heat. Cover grill; cook 6 minutes, turning once, until of desired doneness.