to grease or not to grease?

[Spinner]

i'm cleaning up a dura ace 7402 8-speed rear derailleur for a project, to include removal of the cage along with the jockey and tension pulleys. the pulleys have plastic (ceramic?) sleaves within. should these be greased after cleaning and before assembly?

[bigbill]

I put a light coat of grease on them. With the metal covers and rubber o-ring, its hard to get any kind of lube in them while they are on the bike.

I used 7400 components on my commuter for years and the RD is one of the most bulletproof components ever. I chewed up a few lower pulleys but the RD always shifted like new.

[giordana93]

well, I would not leave them dry, but it is a little hard to get grease into such tight tolerances. I usually put a drop of some tenacious oil when assembling, then maybe a bit of grease to help lessen water penetration, but usually just stick to a good penetrating oil. that 7400 series stuff is bulletproof.

[Brian Smith]

The ceramic bush(ing) was supposed to be better at coping with unlubricated conditions than the bronze counterparts on other pulleys. If I had it apart on my own bike, and there was any more wear than the new condition, then I'd fill the gap with ample grease and reassemble it, but otherwise I'd go either completely dry or just a drop of some very low viscosity chain lube. You don't want to trap contaminants in the area, or the rotating pulley will suck it into the bushing where it will do damage.

Replacement rubber seals are available for the pulleys in order to keep the bushings shielded. It's always a bummer when a pair of pulleys has to be replaced due to bushing wear rather than tooth damage, since the bushing wear occurs from abuse or negligent maintenance, and not due to just normal wear. The replacement stock pulleys for that derailer, if necessary, cost enough to make it preferable to just buy a new derailer.

[pdxmech13]

a lite lube on the ceramic bearing and grease in the rubber seals to prevent contamination.