That sounds like a difficult job. The BEST thing you could do is use styrofoam for the bottom half of the tire & stack layered cake for the top half of the tire. Does that make sense? If you try to make the whole thing out of cake you're going to have a very hard time supporting it. Please feel free to message me if you have any questions. I'm sure there is a better way to explain this!
3/10/10 at 1:07pm