[M. Mellott]

You plan on using 25-series chain to drive the omnis...how will you tension the chains? Also make sure the alignment between each pair of sprockets is acurate.

With 8" wheels and a 5"-wide plate (assuming wheel centers are in the center of the plate--at least it looks that way) gives you a 1.5" ground clearance? Should be OK.

I have to agree with others that you need more meat on the side plates...1" on the webs at least, and big radii in the corners of the pockets. Always start with a strong base, even if it's not for competition.

80/20 is good stuff, but you have to watch that the bolts holding the frame together don't come loose--they always seem to eventually. If you're not going to take it apart, you may want to consider Lok-tite (or tack welds).

All that said, it looks like a solid, simple design that should go together very quickly.