When you put it all together, your tire will look like the picture (shown without the hubcap).
We will add a couple more details to the wheels. Create a 20 sided cylinder and adjust it to make the shape shown in the picture. You could also draw a spline and do it that way but I preferred using a cylinder because it gave me more control. Make sure it fits snugly behind the rim. The "Connect" tool works well for adding edges.
Draw a spline and lathe it to create the cap shown for the front of the brake drum you just created.