Originally Posted by
ThermionicScott
Being primarily a user of Shimano bottom brackets and cranks, I'm curious (in the spirit of friendly discussion, not argument, of course) where their guidance as to dry or greased can be found. My UN55 bottom brackets generally have a film of grease on the tapers that I figure is leftover from manufacturing or placed on for shipping. The included instructions don't say anything about stripping them to dry metal, so I haven't been. I haven't seen anything in the techdocs, either. Thanks.
Moving metal parts or interfaces generally have a film of protective wax or oil on them to prevent rust in transit. It is not generally intended to be used as a functional lubricant.
While Shimano (unlike Campagnolo) give no explicit instruction to degrease the taper prior to installing the cranks in their tech docs, they do explicitly instruct that grease be used on the threads of their BB cups: "Apply grease to the bottom bracket before installing it." With a pictogram of a little grease tub and an arrow pointing towards the cup threads.
As no such explicit instructions are given for greasing the tapers, I infer that they do not want that.
If, however, a crankset came factory-prepped with grease in the tapers, I would use it. Again, I am open to exceptions when manufacturer-specified.