Hubby is turning 40 and I've never had time to make him a fancy shmancy cake. SO - here is his paddle tire cake for the big 4-0! It is made from 3, 12 inch rounds - about 6 inches high. The rim was made prior to completing the cake - I used a 6inch round cake pan turn upside down, dusted it with corn starch and laid my fondant on it, pressed it into the molding of the edge of the pan and onto the table, then used a pizza cutter to cut about 1/4 inch around the pan. I let that sucker dry for a few days. I also pre-made the bolts and air intake thingy. Once they were dry I aiirbrushed them silver. After assembling the cake and covering with fondant, I used the same 6 in cake pan as a guide to cut a hole in the center of the cake (it took a few tried to get the depth right). Then sunk the silver rim into the hole and made the paddles by cutting 8 5inchx1inch rectangles out of fondant mixed with tylose. I rounded the top/end corners and folded them into an "L" shape and glued them in the cake. Done!