How to subdivide a triangle fan (with some of the tris being ngons)? I have a following mesh, in which I have marked the faces I would like to subdivide:



I would basically would like to add an inner ring to this fan. Subdivide doesn't work with this as some of the triangles are actually ngons due to the holes going through the wheel (well, it does something, but the result is far from being clean).

What I want to do is to create a bearing hub. Here's a screenshot of how this looks like with the bearing superimposed:



So what I would like to do is to insert an inner ring (or even two) into those selected faces to create an outwards-extruded hub for the bearing.

What is the clean and efficient way to achieve this?
The easiest way would probably be to Vertex Bevel (Ctrl+Shift+B) the middle vertex.