From:
"What type of oil or other lubricant, if any,?is recommended to add to that hole found in Campy NR hubs (circa 1980)?
Paul Andrews Ft Lauderdale, FL, USA"
hi Paul,
The standard practice is to ignore the hole and regrease the hub in the normal fashion. Rumor has it that the hole was used to add oil, in the case that the owner was using oil lube. Maybe the intent was to freshen up the grease with a little oil, similar to the small oil ports on some older BB's?
The fact that you don't see other hubs with the same holes and clips tells you that this wasn't a widespread practice in general (although I seem to recall seeing a Shimano hub with some sort of clip?). Even the Campy track hubs of the day didn't have the holes and clips. Same for the mid level Campy Nuovo Tipo hubs.
regards,
Steve Kurt
Peoria, IL USA