Originally Posted by
HillRider
Well, waddaya know. This is the first Shimano hub I've ever seen with bearing cages. So, it does seem to be an assembly error on Shimano's part.
I'd replace all of the bearing balls with those from the same lot number rather than just adding one to make up for the missing ball. I'm also one of those who recommend a full compliment of loose balls and discard the retainer.
The tolerances on even the 200 grade bearings shimano uses on some of their hubs are so close that the idea of a lot number match is useless.
I use grade 25C and I know that they are overkill.