ORIGINAL: HelisRule
I know, I need to be careful not to damage the bearings as they apparently have to be purchased as part of a whole darn set, which of course is more $ than the average part.
When you do feel that you need new ball bearings along the main rotor shaft, use these (or the like): [link=http://www.hobbypeople.net/gallery/256965.asp]XTM Ball Bearings[/link] - they're only $9 for four bearings instead of $35 for the Axe bearings set. I changed to the XTM bearings out of necessity a couple months back and the difference was huge!
Oh, in case you haven't run across this: [link=http://www.rcuniverse.com/forum/m_5579975/tm.htm]
Alternative AXE CP parts thread[/link].