Yes, I understand that you're using a convection oven, but all that does is ensure that the surface of the object is heated evenly. If it's of even thickness throughout, the entire mass of the object would be heated evenly as well, but if it's an irregular object (like a wheel) it's going to take a very long time (> 10 minutes) for the inside of the heaviest areas to get as hot as the surface.

If you were to put a bowling ball into your oven, do you think the center would be as hot as the outside surface after 10 minutes? NO. Give it an hour or so at that temperature and yes, it'll get there, but NOT in 10 minutes. It's physics. I can go dig up the equations if you like.