Thanks Sam! I bought those tires on Ebay. They were listed as Clint Freeman's, but when I got them they are solid cast resin. I don't know that Clint Freeman ever sold solid hard cast tires. Who ever made them, I really like them.
Thanks!
I'm using Ertl style rear outer rims, so I made my pulleys hollow. They look like the real thing once the tires are on. I made the pulleys by gluing split rim rings together. I used a rubber band for the drive belt for demonstrative purposes. It's been my experience that rubber bands rot very fast, so I don't think that I will use one permanently. I'm still experimenting. Here's what it looks like.
IMG_5823 by Brian Smith, on Flickr
IMG_5824 by Brian Smith, on Flickr
IMG_5822 by Brian Smith, on Flickr