I am wanting to get a spare for my recently acquired RT178. Only thing hanging me up is whether the factory wheels are a 13" x 4.5" or 13" x 5". Wondering if this even matters being that it will be used for a spare tire only? The stock tires are a Carlisle ST185/80R13. Any help would be greatly appreciated. I don't want to chance running around without a spare any longer. Thanks in advance.