@hamrack 3N80 can be serviced too, the guts are available separately as I found out when mine failed. Think I payed €30ish for a kit and when you take it apart you can access the bearings. Quite hard to do if you want do get at the bearing specifically though, there's a wire that's prone to snapping during the process and then you need new innards anyway... Here's a link but it's €41 now apparently: http://bicikli.de/shop/SHIMANO-spare-part-Y-2Z498010-DH-3N80-INTERNAL-ASSEMBLY-AXLE-LENGTH-108MM-Shimano-Code-Y2Z498010
Yeah, I know you can swap the internals as a whole but it seems wasteful if it's only the bearings that need attention... Much the same as the Shimano hub gears.
@hamrack 3N80 can be serviced too, the guts are available separately as I found out when mine failed. Think I payed €30ish for a kit and when you take it apart you can access the bearings. Quite hard to do if you want do get at the bearing specifically though, there's a wire that's prone to snapping during the process and then you need new innards anyway... Here's a link but it's €41 now apparently: http://bicikli.de/shop/SHIMANO-spare-part-Y-2Z498010-DH-3N80-INTERNAL-ASSEMBLY-AXLE-LENGTH-108MM-Shimano-Code-Y2Z498010