Just FYI to enyone else building this. You can't really unspool the wire like the tire is representing. The reason is, the spool it too heavy and the wire can't provide enough force to turn it before breaking. It's best to put the spool straigt up on the floor and let it unravel itself off the top. This way there is no tension.
Edit: And i know what you're going to say....what about the picture above. It appears to be a heavier wire. Even so, once it gets spinning it remains spinning and when you stop the spool....same deal keeps spinning and then you have a mess of tangled wire. (this is from experience)