The wheels where perched from Tower Hobbies  (Dave Brown Lite Wheels 3").  I then prayed apart the two nylon hub inserts, and riveted a large round horn on on of the nylon hub inserts. Then I drilled a hole large inafe for the servo screw head to go into.

Then the wheel was then snapped back together. I made two of these wheels.

 

The caster was made from a small tail wheel and a .072" push rod. Bend the push rod as on the picture. The brass eyelets are there so the assembly wont bind.