Originally Posted by
BCRider
Those must be some high zoot calipers if they are using ball bearings instead of bushings.
Without seeing the way the pivot is made and how well sealed or shielded it is it's hard to say what is the best method.
The caliper in the picture appears to be an Ultegra 6403 dual pivot, the same basic design as the 7403's except the caliper arms are painted instead of polished and clear coated. The little ball bearing bushings have a stainless steel flat washer on each side to make a sort of sandwich, that when installed correctly nestles into the caliper recesses pretty well. So it does get some protection against the elements. In fact, using grease on these tiny ball bearings gives the user some peace of mind at disassembly time because the goop from the grease will contain those tiny balls as you set them out on a pan to clean.