[philso]

How much weight does your CAD program say that all those cutouts in the tubing will save? Will the tubing still be strong enough? There are 16 long bolts tying the corner gussets to the tubes. How much weight can you save by riveting the gussets to the tubes instead? Will these bolts crush the tubing, especially if you have removed so much material from the tubes. Using a triangular piece of 1/8' material instead of an L-shaped piece of 3/16" material would probably give you more stiffness and possibly lower weight. The pieces outside of the wheels have cutouts with sharp corners. Do you have access to manufacturing processes that can do this? Will these sharp corners cause stress fractures? Do these two side pieces attach to the front and rear tubes? You may want to make the flanges on these side pieces larger so that they will be stiff and can be riveted to the tubes. Are those pulleys on the wheels for belts to connect the 2 outer wheels on each side to the middle wheel? What do the belt runs look like?