Been there, with a GM with a similar issue. The manual stated something about putting the spare on a rear, then, taking the good rear and putting it in the fro

Been there, with a GM with a similar issue. The manual stated something about putting the spare on a rear, then, taking the good rear and putting it in the front. The rotors on the rear were smaller and could accommodate the spare. Obviously a moot point if one has two blown tires.