On Friday, August 17, 2018 at 6:25:19 PM UTC-5, bob prohaska wrote:
What's the conventional wisdom for setting preload on
Shimano hub dynamo bearings?

On a normal hub I'd adjust the cone finger tight and
set the locknut without moving the cone. The dh-3n20
hub is quite a bit more limber owing to the diaphragm
like ends.

If more preload is needed, how much?

Thanks for reading,

bob prohaska

This video may be helpful: https://www.youtube.com/watch?v=oXptXRqxj9c
AFAIK, in general cup/cone bearings are meant to be adjusted for very slight (if any) preload, but certainly no slack.

If I'm right, the cup/cone bearing is on the non-output side, with a cartridge bearing on the output side. It's probably harder to get the bearing adjustment right on a dynohub because of the interaction between the magnets and the poles of the stator, which give the hub bearings a sort of "notchy" feel.

For comparison, replacement of the cartridge bearings in another dynohub (Dahon "Joule") is described he https://hubstripping.wordpress.com/2...comment-105597
Steve