Preheat oven to 225 degrees.
Combine all dry ingredients in a bowl. Divide spice mixture in half. Mix one half of the spices with the mayonnaise. Reserve other half for sprinkling on the ribs.
Place large pieces of foil on a rimmed baking sheet. Cut ribs in half, in needed, so that they fit on the baking sheet.
Set ribs on the foil and baste with the mayonnaise mixture, turning to coat on all sides. Wrap ribs completely with foil and place on the baking sheet. Bake for 3 hours.
Remove the baking sheet from the oven, and carefully unwrap the ribs. Sprinkle the remaining half of the seasoning evenly over the ribs, being sure to coat both sides well.
Place ribs on a preheated grill or broil in the oven. Cook until the coating is browned and bubbly.