We used Colsons last year on our pivot drive and were very satisfied. See photographs:
http://wiki.team1640.com/index.php?t...0412_csm-2.jpg
http://wiki.team1640.com/index.php?t...27_ csm-3.jpg
It was not as easy to install a sprocket as with AndyMark or VexPro, but these wheels are designed to accept sprockets. Still, not so difficult.
We opted for AndyMark HiGrip wheels this year. Light, inexpensive and easy.