In all honesty I know nothing about the shaft, the one designed by Porsche anyway, and until today have avoided opening/reading "any" thread/forums debating on that subject. My Bearing is the best-in-the-world (20 years old now!).
However when I saw "roller" bearing as the title something told me that the IMSB business was obviously going out of control. Rollers bearings aren't necessarily a synonym of "performance" (e.g. think slow locomotive drive train applications). That's possibly why this particular thread caught my attention and raised curiosity.
You are correct Markus. You have more physics involved on rotating mass than one can imagine. Kinetic energy/velocity, momentum, gravity, floating design (or not), centrifugal force (although anything spinning <8000rpm doesn't really create a whole lot of that), dynamic energy e.g. during accel & decel of the balls/rollers. Did I forgot friction and thermal expansion?! Tolerances?!
You call this "dynamic" Markus. Personally (and my m.eng professor would agree) I call this an every engineers' nightmare
