16)
The base of the wheel is already completed,
lets move to the last 2 details. Select
the exterior polygons of both sides:

17) Make sure that Use Pivot Point Center
option is selected and than use Select and
Uniform Scale tool to flatten those polygons
a little. With Use Pivot Point Center option
3ds max will use as reference the center
of the two selection group to flatten them
separately.
18) Now change to Use Selection Center option
and do the same thing, the polygons will
be moved to the center of the object breaking
the ball looking of the wheel.
19) To finish the model, lets make a little
detail in the center of the wheel. Select
the middle vertice in the center of both
sides.

20) With Chamfer tool, create a new circular
group of vertices.
21) Back to Polygon subobject, select the
two new polygons created and use Extrude
Tool with a negative value to create a hole.

22) Select all polygons and use Auto Smooth
again to ajust the smoothing groups and
it's done. Since this wheel will not be
in prominence, we will not need to worry
about it details to deep.
