I made more room in the back of the robot for pinewood derby car weights (to make the robot drive better on two wheels) then changed the robot to have four wheels (which eliminates the need for the weights). I modified the washer part of a wheel hub on Printables to have a pulley for a belt to drive the front wheels from the back wheels. The file imported into Fusion way bigger than it should have been, which made me do it over twice when I realized. Found an Amazon listing for shoulder bolts which will be axels for the front wheels. I also modified the front attachments to touch the floor with the new wheels.