interesting reading about your diff takes on these parts, but one thing I can reasonably comment on is how mtn bike hubs seem to have really really improved on stopping water, dirt etc getting into the bearing area. I recently took apart and serviced the hubs on my old Rockhopper. These wheels were replacements for the originals not long before I bought the bike from my brother-in-law, which makes them maybe 8 or 9 years old. I've ridden this bike fairly regularly, not a ton of mileage(and not crossing rivers or riding in deep mud) but in all those years I never opened the hubs, and they always felt good with the "fingers test" of moving the axels around.

What really impressed me when I did take them apart was how well designed the seals were, and sure enough, the grease was still very clean and abundant, and the surfaces looked quite good.

It would seem to me that while bearing size etc is one thing, how well stuff is kept away from the innards is also a big factor in the longevity of a part.

thoughts on how this aspect of the diff hubs you guys are discussing is diff from one to another? Have any of you taken them apart to see the diff in seal qualities and/or design to stop stuff getting in?