Keith Fitzgibbon's highly modified Thorens TD160. A very different approach.
When a plinth is not a plinth............. In describing my 160 some folks are getting confused with the purpose of the plinth. According to the dictionary a plinth supports something, and in the case of most Thorens TT's this is true. In my build, though, the Thorens plinth is technically no longer a plinth, simply because it no longer supports anything. The plinth is now the concrete table which the springs sit upon. The Thorens 'plinth' is merely a box with no other purpose than to look pretty, something I think it still does well.
The Maxon motor resides in the chrome housing.........the tensioned graphite shaft places the motor outside the box, from where it transfers prodigious torque to the outer platter via the mylar belt. The motor speed is controlled by a Mark Kelly (he'll pop up in a search) designed speed controller.
Yes I thought about the bearing too, but after a hundred hours I can't detect any problems; it's quiet and smooth. If I encounter wear down the road, your suggestion makes sense. For now though 'I ain't fixin' what ain't broke'.
Strangely enough, after trying numerous platter balancing techniques, from floating the platter in a water borne 'boat', to using scales sensitive to .5 grams, I found the best balancing tool was my hand. I'd spin the platter in its sub chassis, loosely holding the sub by the bearing, like you would hold an ice cream cone. In time, I was able to position the three inmost weights shown in the outer platter for perfect balance. It's uncanny how the slightest imbalance will induce a significant wobble in the platter when held this way. When it's right, you clearly feel it.
Adjusting the belt tension is quite simple, unlike what the pictures may lead you to believe. The nylon clamps around the motor shaft provide good 'stiction', allowing the motor to be aligned for azimuth, and moved in and out relative to the platter. Once set, it stays put.
The Thorens subframe is stiffened by bonding a sheet of honeycomb carbon fiber plate and a thin-walled aluminum beam beneath. BTW, the four spring setup provides excellent 'jounce'. Getting #4's location right is the secret, which is dictated by arm and board weight. Balance, geometry and tension is everything in this design.