You can make a set of wheels out of some .020″ music wire, 1/8th balsa and some paper. I bent and snipped the wire using needle nose pliers. I made the wheels by cutting them out of 1/8th balsa. I drilled a hole in the middle of each wheel. I made axle tubes by rolling up a piece of paper very tightly with craft glue. I then inserted the axle tubes into the wheel holes using craft glue. Works great! Check out this Squirrel with wheels! Another method is to make the wheels out of cardboard. I have also heard that you can make the hubs out of the shafts of plastic q-tips.