I've been collecting some CAD models for commonly used Colson wheels since they've been becoming popular in FRC and the CAD is pretty difficult to get a hold of, and I've decided to share my collection: https://drive.google.com/folderview?id=0BxNpey1R08BIZlNwYVpMeW9CWW8&usp=sha ring

Wheels I have so far:

3" x 1.5" Performa grey tread
4" x .875" Performa grey tread
4" x 1.25" Performa grey tread
4" x 1.5" Performa grey tread
4" x 2" Performa grey tread

The 3" x 1.5", 4" x 1.5", and the 4" x 2" are all compatible with the WCP Colson hubs. The rest need to bored out to a 1 3/16" bore, but since it's a common size it shouldn't be too difficult if you have the resources. For the shorter ones you may need to shave the hub down a bit, but it'll still work fine. As for the 4" x 2" wheel, the hub will be slightly short, but it will still support the wheel just fine.

If you have requests for wheel types and sizes to get, I'd be more than happy to work on finding an appropriate CAD file for the wheel.

Hope this is useful!