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:

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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:

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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?

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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.

  • 2
    Note that - if you didn't already know - G Pulley stands for 'guide pulley', as opposed to tension pulley. i.e. it matters a little which one goes where; the g pulley is the top one when you come to reassemble
    – Swifty
    Apr 24, 2022 at 21:16
  • 1
    @Swifty Thanks for the pointer. I took a picture and some notes beforehand about the locations, and I found an old Shimano manual with an exploded diagram of the derailleur where you can read "G Pulley" and "Narrow" on the jockey wheels.
    – SSilk
    Apr 24, 2022 at 22:48
  • Remember, jockey wheels are on the low-load side of the chain's path. They're not under a lot of pressure, but they are in a dirty area of the bike. Cleaning them at all will have improved their function enormously.
    – Criggie
    Apr 25, 2022 at 4:24
  • 1
    Updated the question to be applicable to both jockey wheels (G-Pulley and Narrow).
    – SSilk
    Apr 27, 2022 at 23:57

3 Answers 3

  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.

  • Thanks for the reply. This made me think of two more questions, which I've added as #3 and 4 in my post. Any feedback on those would be appreciated as well.
    – SSilk
    Apr 24, 2022 at 20:49
  • 1
    Great point about threadlocking the pulley bolts. I’ve seen someone’s lower pulley fall off mid-ride; we couldn’t find all the necessary pieces, so it was a ride-ender.
    – MaplePanda
    Apr 28, 2022 at 6:09

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.

  • 1
    @Sam I'm not about to go disassemble my der to get you exact values, but it's on the order of 12mm outer diameter or so. Inner diameter is 5mm. Bearings start at the Ultegra level; DA gets ceramic bearings.
    – MaplePanda
    Apr 29, 2022 at 0:42
  • 2
    @Sam Sorry, I probably should have written "I'm too lazy to go disassemble..." instead. My bad.
    – MaplePanda
    Apr 30, 2022 at 1:22

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.


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