Third one since I began riding in March:



This one looked nearly brand-new. Are the rest going to start going soon? I will prolly run it for a little while, tho normally I would replace a broken part right away. May have to stock up on some Bullseyes.

Check your NR and SR pulleys!

DD

Actually, though I have never really thought about it before, I have seen more cracked Campy rear derailleur pulleys than any other brand. Wonder if Campy ever hooked up with Dupont?

Putting down too much power. You beast.

Yup, they do that. It's not wear or abuse, the plastic has shrunk, that's all .

It's the effect of time. Plastics don't last forever, despite what people think. Campy pulleys didn't crack BITD. But it's 40+ years later now.
There's more than 100k miles on these pulleys. Can you tell? I never saw the point in replacing them, since they still work fine.

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Good argument for the auld metal pulleys with bearings.

When I saw your header thought this would be a thread anent saddles.


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Thats just stress relief. Good for another decade.

I thought it was pretty well established that this was the fate for that model of Campy pulley. Mine have all been preemptively replaced with Bullseye pulleys (but that's just because I've always preferred Bullseye to pulleys with bushings). A few of those Campy pulleys are cracked too, but I don't recall if that happened before or after they were put in the parts box.

As long as we are sharing sad stories, I recently had one of my Bullseye pulleys freeze up on me! It hadn't seen that many miles, but somehow the grease had managed to wander off and be replaced by a bit of rust.

I only had one spare Bullseye pulley, so I started looking around for a modern replacement. The red pulleys at Velo Orange look like decent replacements... although I'm not sure how I feel about the holes in each tooth. I ended up buying a set of Tacx pulleys, model T4000. With the assorted plastic inserts, they will fit fine on the 5mm and 6mm bolts of my vintage derailleurs. With the inserts, the pulleys are 9mm wide. The Campy pulleys are 10.9mm wide, and the SunTour pulleys are 10.3mm wide, so I may have to use some of the Bullseye washers to shim the Tacx pulleys. (the Bullseye washers are 0.9mm thick)

Are there other pulleys (that are in production) that are a better fit to our beloved vintage derailleurs??

Steve in Peoria

While I do know these have a tendency to crack, I thought it weird so many picked this recent 5 month period during which to do so. Also they all looked fairly "young" in comparison to some of my still-surviving pairs.

I recall seeing a pic from [MENTION=135635]scozim[/MENTION] a few days ago showing sheared teeth on a RD pulley. I figured that could be the result at some point, but don't have the experience. I'll keep going on this one for awhile; I don't currently have anything with which to swap it out!

DD

On my short-ride/club bikes I keep the old jockey wheels, cracked or not. But on the long haul riders where I want to minimize the risk of failure I've replaced those with the Soma replicas - they're tough and look correct.

.

The Velo Orange pulleys work fine with NR.

Top

Maybe take some MEK and a vice to weld it back together?

Those would be perfect. Have you a link?

DD

You can replace the bearings in Bulleye pulleys. I did this in one of my sets. Just read the bearing # off the plastic shield on it. I seem to recall a 4001 or something like that. I would go for a good bearing like an SKF or something if doing it over. I just used a pair of sockets in a vise to press the old one out and new one in.

Those look tits-ahoy!

Just thinking out loud...I wonder how easy/effective it might be to fill that gap with epoxy and sand any excess epoxy smooth. I think that might be safer than running them into the ground with the open crack. Having snapped off a derailleur hanger on a nice frame once before, I don't like the idea of risking anything that might cause a catastrophic RD mishap.

That said, I'm also a fan of Bullseye pulleys. However, the days of stocking up on those cheaply has long passed. Sometime you can score lightly used Bullseye pulleys on used derailluers if you are vigilant.

I haven't tried the Velo Orange pulleys, but my experience with some drillium CNC'd alloy pulleys is that they can be noisy...clickety clack.

A few weeks ago I bought some JB Weld two part (urethane) Plastic Bonder to try precisely that on some 1972 NR pulleys which exhibit minor early cracking. They came with a '72 Falcon I'm using for the Clunker Challenge. I'll report back here when I have some results.

I'm also wondering if Aerospace 303 (which is recommended in the hood reviving thread here) might restore old pulley wheels and preclude cracking? I don't have any of that on hand, yet.

Mine was on a Simplex, which has probably happened 3-4 times on the various ones I've had. I've usually swapped for old Shimano Tourney pulleys and they've worked well. But, I have to admit the metal Bullseye pulley's are becoming more appealing.

https://velo-orange.com/collections/...heels-10-tooth

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When I looked closely at the ones that cracked on me, it cracks along a line where the plastic meets up in the mold in maybe the far end where the plastic was injected into the mold.
I think this was the case, because I can see flow or swirl patterns in the grey coloring of the plastic that shows this. The plastic inside the mold must not have been hot enough when this happens that the plastic material does not fuse molecularly together completely at that line when it meets up in the mold?
Sort of a built in weak point,made during manufacturing, not on purpose, of course....Stress and the off-gassing of chemicals from the part must then conspire to cause it to crack at that weak point after many decades of use.
Just my theories,,,,
I bought those black replacements from American Cyclery, a few years ago in SF, that I think were made for and sold by SOMA and they so far have been working out really good and look very good.

that's an excellent suggestion! Certainly not much to lose.

For those interested, the bearing is marked as a 626D, and the web suggests that it is widely available.
Here's a shot of my spare pulley, just to confirm the marking:



and for anyone curious, here's the pulley that managed to lose all of its grease. I'm still wondering about how that happened. It doesn't have that many miles on it, and I would have bought it new. I've repacked it with grease, reinstalled the seals, and it is back on the bike. I guess I'll see how long the bearings last.




Steve in Peoria

I'm thinkin' there is a lost opportunity here:

NOS Campagnolo pulley cracks! Make your old bike look new again.

Light shop wear.
BIN $45 each, or $95 for matching pair.