[Gabe]

For Triple Play, 254 graciously gave the dimensions of their wheel to 604. We changed the design to better suit our robot, keeping the width and diameter the same, but changing the spoke design. These wheels are a nice combination of functionality and beauty.
About your material choice, I would go for 6061 aluminum instead of 7075. That alloy costs a pretty penny, and is completely uneccessary. A quick glance through McMaster-Carr puts 7075 at twice the price of 6061. Our wheels for 2005 were machined from 6061, and for Aim High our wheels were 6061 as well.

These are our 2005 wheels, very similar to 254.