Car

There are many methods for building a wheel, I'll describe a simple one, but from there you could develop to a complex method.
First will create a cylinder and a tube with 20 sides. The cylinder must be inside the tube.

Next we select the vertexes 2 by 2 and we scale them (see the image). Then we weld the vertexes with the vertex of the cylinder (in the first place we attach the tube to the mesh). We must delete the interior faces that are resulting from the welding of the vertexes (it's best to do this before the weld but it can be done also later). For a better effect we can select the central vertexes and spin them , or we could erase some faces from the middle to make the impression of holes.

We delete the faces from the exterior part of the mesh (that touches the tire). We apply a mesh smooth to see how it looks.

We return to edit mesh and select the exterior edges (marked with red in the image) and the interior one and we scale them:

We apply then a mesh smooth with 3 iterations:

The tire: We create a circle and a spline like in the image: We loft the spline on the circle and obtain the tire shape. If the tire is upside down we select the object, then subject (in loft) select spline , and we rotate the spline with 180 degrees.