Sealed bearings with the rubber type seal are pretty much standard fare on most live axle rear ends so why not use what works with extra grease packed in as usual will guarantee no failure due to water ingress.
By the Way BMW Motorcycles eventually solved their gearbox issues with some models such as the 1100 GS adventure style bike by going to what they referred to as a "Clean bearing style gearbox version".
What that actually meant in reality was all the gearbox bearings that are usually open to the oil supply in the gearbox are replaced with Rubber sealed on both sides grease packed bearings from the factory, This means that any of the hardening that may flake off gears etc cannot enter into the bearing tracks where hardened metal will damage the bearing leading to much improved bearing life and therefore better gearbox shaft alignment and longer Gear life as well.
So when it comes to bearings think about the application and go from there as Sealed bearings with rubber or neoprene type seals are better then either open bearings or steel shielded bearings as they are more capable of keeping metallic foreign objects out of the critical Ball and Groove section of the bearing.
Other things to note the above bearings listed note C3 this means the Radial Clearance and is quite common for Automotive type applications as when a bearing is fitted it is usually an interference fit that compresses however minutely the outer housing and often expands the inner housing when fitted to a shaft as an interference fit also, This will then pre load the cases both inner and outer of the bearing reducing the radial clearance, That is why they specify such clerances as C1 and up with the bigger numbers such as C3 denoting more radial clearance.
Radial clearance being if it was too much you could move the inner section of the bearing up and down in relation to the outer or side to side that is radial clearance and it is also needed as when the bearing reaches operating temperature the different parts also expand reducing further the running clearance.
Edited by coxy, 01 February 2014 - 06:54 AM.