I'm going to get a 5x8 frame with 12" tires but I have a problem with the white spoked wheels that come with the trailer frames. My white spoked wheels on my horse trailer started rusting right away. I would like to get some 12" alloy or aluminum wheels but I can't find them in anything but 13". Does anyone know if they make 12" wheels in anthing besides white spoked? Am I going to have to change to 13" wheels?