RE: O.S. .46 AX Replacement Bearings - remove shields?
I generally don't worry about pulling one of the shields on the front bearing -- the oil gets past them just fine anyway -- but it's a good idea to pop both shields from the rear one - or just buy unshielded bearings in the first place. I get mine from RC-Bearings.com and the rears come without shields -- and they have a polymer cage as well which is a *lot* safer for your engine.