Our first year wheels were made out of wood. We couldn't afford anything else and didn't have much time. They worked OK, except for the really cheap "rubber" mat tread we got at Home Depot or somewhere. It was a dual-wheel setup, with the sprocket sandwiched in between the wheels, live axle with outboard bearings. They were made from glued 1 x 4 pine boards (the maximum size wood allowed that year) sawed out on a band saw.
That was back in the days when the drill motors and transmissions still came with the plastic drill housing/handle. We just sawed off the handle and used the cordless drill case as the motor mount
