[Garret]

Generally speaking, needle bearings will handle radial loads far better than ball bearings. However the disadvantage is that they require the shaft to be completely round for the length that it is contact with the bearing, this is because their is no liner (can be purchased separately) inside to prevent the rollers from coming out. The thing about needle bearing not supporting axial load is due to the fact that axial loads will just push whatever is retaining the shaft into the bearing housing, this means that you will need some sort of additional bearing/bushing for axial loads.

My experience has also been that despite better load capacity they don't like to go as fast as ball bearings (though I don't really have any quantitative data to confirm this). I am pretty sure we have used them in some of our really old drivetrains and our swerve (for steering). Needle bearings require different design considerations to work well, I don't see any reason that they wouldn't work on a WCD if everything is taken into consideration.