I haven't seen any ball bearings in my wheel pilot. However the manual does recommend to wash the rollers with clean water
as part of your maintenance
but doesn't recommend any other lubrication. Raymarine also have a refurbishment kit of some sort which replaces these rollers I believe. The common problem relates to the rollers creaking or squeaking and you should find a number of threads that deal with this issue.
My findings are:
-Lubricate rollers with a PTFE dry lubricant works best. i have also drilled a couple of holes in the back so I can spray lubricant direct onto the rollers.
-Don't use any hydrocarbon based lubricant as this will tend to swell the plastics and make the problem worse and you may never be able to fix it
-Use of silicon lubricant was not successful in my case
-Be careful not over tighten the adjustment in the belief it will resolve the noise
. This will destroy your belt and put more wear than necessary on the gear
and even damage components.
Tip: If your tension adjustment is hard to get at, replace the allen head
locking screw with a 8mm (I think) SS metal thread and wind
a nut hard under the head
to make it proud of the adjusting knob so you can get a spanner on it.