Originally Posted by
Lenton58
In the case of hub bearings: the loads are much greater, and
any imperfection we can feel in our hands as we rotate the axle will (AFAIK) be multiplied when it is loaded.
I totally agree with Lenton's statement. I've found that other (i.e. non-hub) bearings may have a "hand-feel" that's a bit rough but still function perfectly under load in regular use (e.g. BB's, pedal, and headset bearings), but that isn't the case with wheel hub bearings. For these, I do not accept anything less than absolute rotational "hand-feel" smoothess after servicing. It is impossible to get this smoothness with cone bearing hubs that have bearing races that are pitted or scored beyond a certain point (or other defects, such as bent axles or out-of-alligment bearing surfaces).
I certainly appreciate the benefits of cartridge bearings, but their benefit over "adjustable" cone & loose bb hubs is mainly that they either work perfectly or they don't, and they supposedly don't require as frequent servicing. As good as they are, they are not perfect. Makers of high-end hubs (like Campy) sgtill use cone & race bb hubs. There is little one can do to routinely service a cartride bearing hub, except to keep it clean and properly tensioned, and perhaps add lubricant, though how you should add lubricant is a matter for debate. You can of course replace a worn out bearing cartridge with a new one, but that is a chore and not really easy.