Classic & Vintage - RD pulley replacements

...for a Shimano 105 "Golden Arrow" RD. I'm looking at http://www.loosescrews.com/index.cgi?c=Derailleur&sc=Rear%20Pulleys&tc=Shimano&id=68605511034 and I just want to clarify: if I need to replace both pulleys, then is the top one the "guide pulley" wheel and the bottom one the "tension pulley" wheel? Can anyone tell me what the difference is between a guide pulley and a tension pulley wheel in terms of the actual structure? Is one actually bigger/smaller than the other? I can't tell from eyeballing it.

Also, before installing, is there any part of the wheel that should be lubed? If so, grease or oil?

Your terminology is correct, but most derailleurs are interchangeable with the pulleys. Depending on the design of the pulley, you may, or may not need to re-lube. If it actually has bearings (some Hurets do, but they're the only ones I know for sure that have them), it will pay to re-grease them, as you would with hub bearings. Otherwise, any grease you apply will likely do almost nothing.

Great, thanks for the clarification, Zorro.

There is a difference between the two, if they are Shimano and depending on the vintage. For indexed and some earlier derailleurs, the top/jockey/guide pulley uses the Centeron design, which incorporates a bit more side play to allow the pulley to center under the freewheel cog. If you pinch the the dust caps in your fingers, you can slide the pulley side to side on the bushing much more than a normal pulley. The Centeron design goes back to 1978, so there is a possibility that it was used the circa 1983, first generation, 105. Usally, Centeron is stamped on the pulley. In friction set-ups the use of a Centeron pulley is not mandatory, but if you have a set with one, using it in the top position will make the drivetrain run a bit smoother.

Campagnolo C Record pulleys, identified by light grey with chrome dust shields use ball bearings,

The better Simplex derailleurs also used ball bearings in their pulleys.

I always thought it was strange that the '60s Campy Record derailers had ball bearing pulleys and the later Nuovo and Super Record derailers used bushings. Apparenty they didn't think that ball bearings were better for that application.

The Centeron design goes back to 1978, so there is a possibility that it was used the circa 1983, first generation, 105. Usally, Centeron is stamped on the pulley. In friction set-ups the use of a Centeron pulley is not mandatory, but if you have a set with one, using it in the top position will make the drivetrain run a bit smoother.


Campy and Simplex aside, you know where I can get this "Centeron" pulley? Are they available anymore, or will I need to do an ebay troll?

This is not referred to as Centeron, so I'm assuming it's not: http://www.loosescrews.com/index.cgi?d=single&c=Derailleur&sc=Rear%20Pulleys&tc=Shimano&item_id=SH-5639837&id=288503631036

(It's 1G 105, and it is, indeed, friction.)


Thanks for the info.

<sigh>

So as I look over this thing, though I did a major cleaning of it a couple of weeks ago (i.e. soak in mineral spirits overnight), there's still tons of crud all over it. The bike and the parts looked like they had been repeatedly ridden through the mud and not cleaned ever since. I have not been able to get to the gunk inside of the 'box' or whatever you call it. And the spring is kind of gritty, as is the inside of the spring housing. So should I drop some lube in with the spring? And would I need to replace any of the other little plastic bits--i.e. the seals around the housing and stuff? Should I put some lube on the plastic? Or silicon spray? And, the jockey wheel doesn't look like it's marked "Centeron." Could I replace it with a Centeron for better shifting, or will it not matter that much on a friction system? What about metal wheels instead of plastic?

Anyone with experience in this, I welcome comments.

Do you have a power washer, or a spray nozzle that can generate some force? I'd spray out the box, then soak it again and rinse it off. The spray should get out a lot of the grit as well. I'd then give it a spraying with WD-40 - to get the water out, and after that dries, put a little silicon lube in.

From what T-Mar wrote about the Centeron, I think it wouldn't make much, if any difference with your friction system. If you're not satisfied with how the jockey wheels spin, or if they are worn, you could just replace them with new ones that fit the pin size. I strongly advise staying away from Simplex pulleys (just in case you're thinking about it) as even NOS ones tend to crack very quickly. Generic SunTour or Shimano should work just fine.

Do you have a power washer, or a spray nozzle that can generate some force? I'd spray out the box, then soak it again and rinse it off. The spray should get out a lot of the grit as well. I'd then give it a spraying with WD-40 - to get the water out, and after that dries, put a little silicon lube in.

From what T-Mar wrote about the Centeron, I think it wouldn't make much, if any difference with your friction system. If you're not satisfied with how the jockey wheels spin, or if they are worn, you could just replace them with new ones that fit the pin size. I strongly advise staying away from Simplex pulleys (just in case you're thinking about it) as even NOS ones tend to crack very quickly. Generic SunTour or Shimano should work just fine.

Okay,

Thanks for the advice, Zorro. The wheels are completely worn, so I have to replace them. When you say silicon lube, does something like Tri-flow qualify? No Phil's Tenacious Oil?

I'll try and find decent replacements. I'm impressed that the mechanism itself still seems to actually work, though.

Okay,

Thanks for the advice, Zorro. The wheels are completely worn, so I have to replace them. When you say silicon lube, does something like Tri-flow qualify? No Phil's Tenacious Oil?

I'll try and find decent replacements. I'm impressed that the mechanism itself still seems to actually work, though.

Tri-flow is what I'd use - because that's what I have on hand. I haven't experimented much with other lubricants, but it seems to work fine for me.