This is a pretty complete drivetrain using the 2-speed gearboxes I posted recently. Total weight is 21.7lbs, excluding motors, lexan plates, and battery box. Outside dimensions are 28" wide, 32" long. The corners are 5" long, so the frame perimeter is exactly 112". Center 4 wheels have a 3/16" drop.
The corner gussets aren’t completely necessary, but my team has found that gussets like this help prevent broken welds late in the season. We have used 3D printed chain tensioners similar to the ones shown. These would be produced with 90%+ fill, or would be made out of ABS. The wheels in the picture are custom 4" wheels.