Preheat the grill to 275°F for two-zone indirect cooking.

Remove the membrane from the back of the racks using a butter knife and paper towel.

In a small bowl, mix the brown sugar, smoked paprika, garlic powder, onion powder, salt, and black pepper.

Generously apply the dry rub all over the racks, pressing firmly so it adheres.

Place the meat over indirect heat, close the lid, and cook for 2.5 to 3 hours until tender.

During the last 15 minutes of cooking, brush the barbecue sauce evenly over the top.

Remove from the grill, let rest for 10 minutes, then slice between the bones and serve.