I make wheels all the time for my Custom Wooden Models.
I use a bandsaw to cut the circles, then use a router table to round over the edges or make the profiles inside. You can route small parts on a router table, the key as you mentioned is holding it. I clamp my wheels in those wooden adjustable hand clamps. You have to reposition the clamp a few times, but its easier then any other method. Its also faster then trying to set anything up to do the same thing.
By the way, whatcha making?
If you need some help making tractor tires let me know. By using an indexing head, a radial arm sound equipped with a dado blade and by having the blade elevated and set at 15º, you can make some staving rear tractor tire wheels.
I have no intention of traveling from birth to the grave in a manicured and well preserved body; but rather I will skid in sideways, totally beat up, completely worn out, utterly exhausted and jump off my tractor and loudly yell, "Wow, this is what it took to feed a nation!"