This is our pre-season drivebase project. It uses the standard AndyMark gears and gear ratios but the gearbox with motors can be removed quickly from the drive train with 6 bolts for a quick replacement if necesary. The 2 gearboxes and 2 drive train modules can be built independently and then put together at the end which allows groups of students to work in parallel. It has an optional 3rd motor (775Pro) which has a lower gear ratio to give more power and speed to the drivebase. The frame components weigh about 1 pound more than the Andymark chassis. It has omni wheels on the front and back to allow for easy turning so that will add a little more weight. Also if the 3rd motors are used that will be about 3 lbs more weight.
STEP files and solidworks files are all posted on GrabCad.