George,


The force of the gyroscopic precession is also a function of the distance of the spinning mass from the center.

This is the reason gyroscope rotors (non-piezo) resemble bicycle wheels, with thin, light spokes and a massive annular weight.
The forces applied to the bearings by combustion and by the inescapable imbalance of a single cylinder engine, are exponentially larger than the forces of precession. Both of these 'naturally occurring' forces, affect both bearings (the front one through the crankshaft).

I have never seen a front bearing 'go south' even with a badly imbalanced prop.
It is not likely these relatively small forces of precession will do it.

As in real-estate, the 'reason d'etre' for the 'heavy hub' is its location, at the furthest front of the plane.