I have a jon boat that has been sitting on its trailer under my deck for too long, the tire are about shot. My bad, I should have done the smart thing and put the trailer on stands and put the tire in my basement. Now I am looking at the 12" tires I think they are and have determined the 5 lug pattern is virtually the same as several automobile wheels. I am thinking of trying a set of "donut" spare tires (buying complete wheels and tires from a junkyard) on my boat trailer. Has anyone tried this? Is it a bad idea?