and you get what you pay for, cheap bearings not Spec ed for the PA will not perform as well, and the inferior front sealed bearing will leak very badly, many times from the start, The ones I use are special quad seal bearings, and work way better than the cheap 3 dollar ones I can buy, the rears are also a special spec and are hi speed Phenolic bearings that have the correct clearance.
I do not sell cheap ones, but do sell the correct ones , they do also have to be pressed on the shaft and then pressed into the case with a contersunk pusher for the front, and a collector for the rear.
Randy
www.aeroproduct.net 678 407 9376