Preheat grill for 400 degrees, or medium-high heat.
Place rib roast onto a large cutting board. Combine rub ingredients and apply evenly all over roast. Tie roast in between the bone with kitchen twine. This will keep the meat from separating off the bones during the cooking process
Place the rib roast bone side down, or if you are using a boneless rib roast just place it on its side. Lift the roast from the ends and rotate it in order to find its center. Using a long, thin knife or sword skewer, pierce through the center of the rib roast, from end to end. Run the rotisserie rod through the hole and secure with the rotisserie forks.
Set the roast up on the grill and adjust to center. Tighten forks as needed. Place an aluminum drip pan filled with 1 cup of water right under the roast. This will allow you to collect the rendered juices for gravy. Grill roast for 3-3 1/2 hours or until the internal temperature reaches between 125-30 degrees (140 degrees for medium done). Monitor the temperature, especially after the 1 1/2 to 2 hour mark.
Using heat resistant gloves, remove rib roast from grill with rotisserie rod still intact. Tent with aluminum foil and let meat rest for 20-30 minutes. Now is a great time to make your gravy with the roast rendering collected in the drip pan.
Once meat has rested, carve off bones and save for later. Slice meat into 1/2" thick slices. Plate and serve.
See below for Drip Pan Potatoes recipe.