Servicing Shimano Centeron Jockey Wheels

Question

I'm servicing my rear derailleur jockey wheels (pulley wheels) for the first time. They have about 20,000km on them. The derailleur is a Shimano Deore LX, and the first jockey wheel I've taken apart is the Shimano Centeron G-Pulley.

I've disassembled and cleaned it to this point:

The two spacers/ end caps (the larger steel washers on the left) just popped off on their own, and the metal cylinder sitting on its own popped out of the middle of the wheel easily. I think that's a bushing. Most of what I'm seeing online talks about prying a cap off the jockey wheel to expose bearings, but it doesn't seem like this wheel wants to come apart any further. And if that cylinder is indeed a bushing, I think that means there won't be bearings, and the bushing is the thing about which the rotation occurs.

There are two little slots on either side of the channel that runs around the side of the wheel:

I thought those might be for slotting a small screwdriver into to pry something apart, but I tried that and nothing else moved. The slotted metal collar that's still inside the wheel also doesn't seem to want to rotate relative to the wheel or pop out, and the teeth around it make me thing it's a permanent press-fit piece.

So I have four questions:

1. Should this come apart any further? If so, how?
2. When reassembling, what type of lubricant should I use? Advice online is all over the place: 10 minutes of Googling suggested grease, oil, teflon, ceramic, other exotic synthetics, or no lube at all. I have on hand Phil Wood Grease, Phil Tenacious Oil, classic WD-40, and WD-40 Silicone. I'm hoping one of those is appropriate.
3. Should lubricant be applied to both the outside surface (blue arrow in first pic below) and inside surface (green arrow) of the bushing, or just outside?
4. Should any lubricant be added to the channels that the spacers sit in (yellow circle in second pic below), or to the outside faces of the spacers themselves?

Note: the second jockey wheel is labelled "Narrow" and is almost identical except the inside surface of the wheel itself, i.e. that the surface that rotates about the bushing, is plastic. Same questions apply to both wheels.

Answer 1

1. No
2. The scattered advice is because your climate and riding conditions should dictate what goes on if anything. For example, someone riding in regular wet weather could reasonably use a heavy oil to resist washout, but for many that would be messy with no advantage. One drop of light oil on each is a good generic approach. That has little risk of being too much, and if it winds up being too little and it squeaks you can just add another drop externally.
3. Given the choice, the only place you want lubricant is between the outside of the bushing and the inside of the pulley's contact with it.
4. That area is a labyrinth seal. It's trying to create a circuitous route for contamination to enter the bushing. You don't need or necessarily want it lubricated. That said, you can use it to wick in some lubricant into the inner part without any great harm. (Or so goes my assumption - as with many things, it's always possible that actual controlled testing could have interesting results).

Of note is you always want threadlocker on the pulley bolts. I've seen them come undone for seemingly no reason other than lack of freshly applied threadlocker, which can be very bad news for the frame or wheel, so I'm pretty uptight about always putting fresh medium strength threadlocker on the pulley bolts, in emulation of how new ones come. I use the gel lipstick style to keep it neat.

Answer 2

The cheaper pulley wheels don’t have bearings and only use bushings. I think the slots might be lubricant reservoirs of sorts.

I would use a thinner lubricant like chain lube because there is not a lot of force on the pulley wheels and they’ll spin more freely that way.

Answer 3

You have disassembled the pulley wheel as far as it will go and still come back together fully functional. As noted in other answers, the type of climate you ride in determines the best lubricant to use. While there should be some lubricant used, the pulley wheels do not bear much load, and thus, the lubrication of choice is not as important as say, lube used in a wheel or bottom bracket.

I ride daily in all weather conditions offered by the climate of the upper Midwest U.S. Four seasons very different from each other. Approximately 3-4 times per year I disassemble my bike's pulley wheels as you have done (and in the course of an overhaul on a bike project). Upon reassembly, I use a light coating of a lower viscosity, Teflon containing clear grease (Super-Lube, by name) on the entire bushing inside and out as well as center of the pulley wheel that has the grooves. I also thin-coat the pulley axle (the bolt that fixes the pulley wheel in the cage) including the threads. When all is back in place including the chain, I'll drip some of what I use for chain lube (Tri-Flow wet lube) on the center of the spinning pulley wheels (back peddling). The product has a thin applicator straw and I'm able to get the lube pretty well where I want it, in the amount I desire. The spinning pulley wheel draws the drips inside well. Less is more in this case as I don't want to flush the thin coat of grease out nor soak the pulley wheels since that will all attract dirt. When I do my drive train clean and lube of the chain (I try for weekly but may average 3x/month), I will hit each pulley wheel center with a few drops of the lube while back peddling.

The short answer is that it may be best and most convenient to use your chain lube at regular intervals on your pulley wheels as well.