I'll take 4 (four) of those NSK steel-on-steel ball bearing then. Those have the same coefficients of friction in both static and kinetic values as of rubber on asphalt! I believe TI is used for its thermal,
durability and non-toxic properties. Properly done, ssteel can be harden far beyond TI... those balls are the ones that carry the load capacity if my memory is good.
I just heard some young dudes talking about this in the R&D center I worked for 20+ years. I was just their janitor mopping floors all day long and know nothing about nothing
sorry for wasting your time!