Preheat your smoker to 250°.
Remove the membrane on the bone side of your ribs. To do this, slip a sharp knife under the thin membrane and work the knife to loosen a bit. Then grasp the membrane by your fingers and peel it away. You may have to do this in strips. Removing the membrane helps to make the meat more tender. Sometimes, depending on where you buy your meat, they will have already removed the membrane. Set the racks aside while making the rub.
In a small bowl. stir together the sugar and all the spices.
Divide the rub into thirds and sprinkle one third of the spice on each rach of ribs, covering both sides.
Insert your temperature probe into the thickest part of one of the racks, avoiding the bones. Place all three racks onto the grates and close the lid.
Smoke the ribs until the internal temperature reachs 205°. This should take about 6 hours. f you check them and they are still not tender enough, allow them to smoke for about 1 hour longer.
Remove the racks of ribs and turn your temperature up to 375°.
Generously brush both sides of your ribs with bbq sauce.
After your temperature reaches the 375°, return your ribs to the smoker, close the lid and smoke each side for about 7 minutes.
Remove from grill, cut and serve with extra bbq sauce on the side.