Joined: Jan 2010
Posts: 9,818
Likes: 1,790
From: Northern California
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
I've been amazed how some cartridge bearings keep spinning smoothly year after year.
Even "dry" ones where the axle spins like a top, ten more years and still smooth, these in my "rain" bike's EDCO hubs, which do also feature an external, well-fitted metal shield.
So I don't jinx a cartridge bearing hub that is free of freeplay and still has a perfectly-smooth turning action by taking it apart or loosening anything. A very small speck of grit will turn a superfine bearing finish into one that is not, and even the slightest bit of side-loading from the quick release compressing the axle might have a seemingly perfect bearing adjustment instead destroying those seemingly ageless bearings!
Any cartridge bearing however, that shows even the slightest bit of audible vibration that can be heard or felt while turning, is in self-destruct mode and surely within the last 10% of it's life.
An external spritz of WD-40, TriFlow or other penetrant that migrates into a cartridge bearing past it's seal invariably drags along some grit that can drastically reduce the bearing's life. Ask me how I know!
Again I advise that axle adjustments allow for the inevitable shortening of the axle due to the quick-release's pressure, orthe bearing life (any type of bearing) can be extremely short.