From how it looks (I'm not familiar with rim drive, more with idlers), the motor drives directly the platter through a rubber O-ring put on it's shaft. I think it's quite a problematic solution: 1) I'm sure they can machine the rim to a great degree of roundness, but it must be matched by the same on the rubber side. I think EMT idlers is a good example here with their machined rubber surface...and even those have roundness problems; 2) The motor is more intimately coupled to the platter than with an idler, which makes it's more visible with all it's cogging.
Also the shaft looks shortish for the 40kg platter, even though it's super hard. Longer shaft=less wobbling (again EMT930/927 is a good example here)
Also the shaft looks shortish for the 40kg platter, even though it's super hard. Longer shaft=less wobbling (again EMT930/927 is a good example here)