Main Problem : how to easily displace the hub from the center of the wheel ? Play around with spokes ? No ! way too painful . But Tim is a carpenter and has access to a router .
So They decided to craft it out of plywood planks . Quick, easy, strong enough, not that awful, and works fine.
Step 1: Wheel building .
Also, we checked the 1/3 rapport was good enough to allow the wheel to spin without rubbing against the frame . It was a wheel from a smaller bicycle .