Old(er) bike, new(er) derailleur, what to do about the hanger?

Cyclo_Tron

New Member
TL;DR: I'm trying to mount a newer derailleur on an older bike. What's the best way to get a hanger that will match the old bike frame to the new derailleur?

Howdy, all. I've got an issue with a 2017 Norco XF3 that maybe ya'll can help me with.

A little history: buy the bike used. It never shifts right. All tuning leads to is which gears are hesitant to shift down, without actually fixing the hesitance. Shop's guess is bent derailleur hanger but that's why it's cheap(er). They were either lying or idiotic but that's a rant for another day. Have the bike for a couple of years, fall in love, etc. etc.

Fast forward to about 4 months ago. Bike is hanging on the wall, decides to drop the people's elbow on my roommate's bike from off the turnbuckle. Wake up to find them both in a heap on the living room floor.

Roomie's Specialized is fine. My bike, on the other hand, suffers a taco'd rear wheel and a bent derailleur hanger (or cage). Shifts terribly. All the tuning and bending I do doesn't really fix the problem (yes, with a new wheel). It consistently shifts worse than it ever did. I start entertaining the idea of replacing the derailleur (because maybe it can still be bent back) and find out the one on it is a replacement. I'm not terribly up-to-date on part's manufacturers but I learn pretty quickly that's it's the worst, oldest MicroShift you can find that still actually works on my bike (depending on how loose you are with the definition of "works").

That would explain a lot and should be a lesson to anyone buying used.

I start looking for a factory replacement. I'm not going to try to bend my way out of a derailleur that has who-knows-what indexing paired with the wrong shifter. Anyways, the factory derailleur is a Shimano Acera RD-M3000 Shadow and finding one, at least for me, was almost impossible. A lot of places don't have any left and the one's that do quote insane shipping times (6+ months). I start learning about matching new derailleurs to old ones, in terms of performance. I settle on the Acera RD-T3000.

Long story short here; I eventually get it fit on, replace the shift cable and housing, and the bike shifts better than it ever has. Photo since I can't yet link to the video of the derailleur shifting:
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You'll note that the hanger is blue and appears to be made of plastic. Both of those things are true. You see, when the RD-T3000 came in the mail, it had an interesting B-screw arrangement that the MicroShift (and, I have to assume, the M3000) didn't have. I end up firing up SolidWorks and making this:

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It takes about 45 minutes to print at 100% infill on a 3D printer. This is actually the second hanger I made for this thing. The first hanger (which is in the first photo) I made before I got the new derailleur in the mail and is basically a direct copy of the factory hanger. You'll notice the c-shaped slot in the latest hanger; that's part of that weird b-screw scheme. The big, square shaped head is for preventing the b-screw from just digging into the plastic and not doing anything.

Here's a few photos illustrating what the new derailleur has the the older one didn't:
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That little c-shaped ring projects away from the derailleur where the old hanger has no such ring (I think). The hanger certainly doesn't make an obvious allotment for it. It's here, along with pictures of the old-style hanger fitting flush against the MicroShift:
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Here's my question: am I doing this right? Ignore, for a moment, that I'm trying to do this is different types of plastic. More on that later. My main concern is if there's an easier way to put an new derailleur on a old bike. Is there another derailleur missing this "c-ring" setup that would mount more easily to the factory hanger? Am I just mounting the one I have wrong?

As an aside, the b-screw works on the derailleur with the groove cut into it. The bike shifts great; however, this process was driven by the fact that I use my bike every day to commute to and from school and I needed it back on the road quick. I'm wondering if I missed something obvious on the way and made this waaaaaay harder than it needs to be.

About the plastic: the first hanger was printed in PLA at 100% infill (maximum density). It lasted about 2 months of twice-a-day riding that included jumping a lot of curbs before it died. Oh well but that's not surprising. The second was printed at 100% infill in PETG. It only lasted about two weeks before I had to dump the bike one day and it fell on the derailleur side. I'm assuming the derailleur more-or-less did its job but, instead of breaking away clean from the frame or bending, it just snapped in half. Not sure but I'm confident it would have lived longer than the hanger in PLA had I not fell.

The reason I'm asking the question now is because I'd rather just buy a metal one that works for this frame/derailleur setup. If no such hanger exists BUT my design is good (read, I'm not doing something silly with that c-shaped groove), I can get one printed in Shapeways in materials much, much stronger than PLA and PETG for about $10. I can have one printed in steel for $50 but I think that would actually work against the derailleur doing its job in the event of a fall. Aluminum, the factory material, is about $103 to print and ain't gonna' happen.

Absolute worst case scenario, I can buy a reel of PETG for about $30 and keep making new hangers (a spool would be good for about 32 hangers). So, there's an emergency solution that keeps me on the road but, obviously, I'd rather put a bow on this thing for good. Thanks for any help and/or expertise!
 

Cycleops

Guru
Location
Accra, Ghana
Hello Cyclo_tron and :welcome: to CC.

To answer your question "the best way to get a hanger that will match the old bike frame to the new derailleur?" Is to get the correct hanger for your frame model. Should cost about $10-15.
 
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Cyclo_Tron

Cyclo_Tron

New Member
That hanger is pictured in the original post. It isn't compatible with the new derailleur, as far as I can tell. I'm not sure such a hanger even exists. Thus the post.

The original hanger is about $32.
 

keithmac

Veteran
When I was looking for a hanger for my lads MTB there was a seller with probably 40 different styles on ebay, all with pictures.

So maybe best having a mooch about on there to see if you can match one up?.
 
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Cyclo_Tron

Cyclo_Tron

New Member
When I was looking for a hanger for my lads MTB there was a seller with probably 40 different styles on ebay, all with pictures.

So maybe best having a mooch about on there to see if you can match one up?.

I'll try reaching out to the sellers and seeing if they typically make (or can make) hangers that can mount a non-factory derailleur to a given frame. I'm guessing there's quite a few different possible combinations out there and the hanger would be a one-off but it's worth an ask.
 

Ajax Bay

Guru
Location
East Devon
:welcome: You might like to scan this thread: https://www.cyclechat.net/threads/goodbye-indexed-gears.279142/
(NB includes images which may shock)
A hanger has two interfaces: one to the frame (drop out) and one to the rear mech. The first is bespoke: you have to find the right one. The second is standard. Just about EVERY rear mech will screw into EVERY hanger. If I've misunderstood you: apologies.
What do you mean "a non-factory derailleur"? Was it made as one-off by some artisan? Thought you said it was an Acera RD-T3000?
 
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Cyclo_Tron

Cyclo_Tron

New Member
Edit: the factory derailleur was a M3000. I replaced it with a T3000.

Yes, in fact; these artisans work in a foreign and distant land known as "Shimano" and weren't selling the derailleur I now have when the bike was manufactured. Thus, it couldn't be attached to the bike when it was built.

"The second is standard. Just about EVERY rear mech will screw into EVERY hanger."
This is where I think I've goofed. The MicroShift the bike had when I bought it lacks that exact B-screw mechanism outlined in yellow in the OP. What was supposed to the the stock derailleur (the RD-M3000), as far as I can tell, doesn't have it either.

I think I found the one image one the internet of the back of the RD-M3000. I'm not seeing that c-shaped b-screw thing:
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Was this an oversight I made when looking for a new derailleur? If there's a difference (in regards to how they fit on a hanger) between derailleurs like the RD-T3000 and the RD-M3000, what is it?
 
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The snag with a plastic hanger is you cannot align it correctly (it won't bend and stay bent like an aluminium one would)
All hangers need to be aligned to a particular frame, you cannot just fit a new one and expect the mech to change cleanly.
 

Ajax Bay

Guru
Location
East Devon
"the factory derailleur was a M3000. I replaced it with a T3000.
. . . "Shimano" . . . weren't selling the derailleur I now have when the bike was manufactured. Thus, it couldn't be attached to the bike when it was built."

[Adopt pantomime style: "Oh yes it could!" In strict time-space continuum, I suppose you are right: does it help your understanding? The interface between an RD and the drop out / hanger is standard and has been for literally decades (massive credit to the bicycle industry - any other interfaces that have stood such a test of time? I have a Pat. 1976 Campagnolo RD which will fit on every one of my twenty-first century bikes.
"The MicroShift the bike had when I bought it lacks that exact B-screw mechanism outlined in yellow in the OP. What was supposed to the the stock derailleur (the RD-M3000), as far as I can tell, doesn't have it either."
Suggest you put the b screw issue on the 'ignore button'. It's function is to adjust for the distance between the guide pulley wheel and the sprockets - unless you have a super large largest sprocket it's a 'tweaking' issue.
"[Is] there a difference (in regards to how they fit on a hanger) between derailleurs like the RD-T3000 and the RD-M3000?"
Nope: as I've explicitly said before.
3-D printers must be amazing to explore, though.
 
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Cyclo_Tron

Cyclo_Tron

New Member
The difference in how the B-screw interfaces with the hanger interferes with how it mounts. It couldn't be ignored. That's why the hanger that was finally installed had the groove designed into it. That whole c-shaped thing is part of how the b-screw interacts with the hanger.

There's a pretty clear difference in what's between the derailleur and the hanger, based on the photos and what I saw when I took the bike apart. The threaded fasteners on the hanger and the derailleur are indeed the same, though; I didn't have to change thread sizes when making the new hanger. The new derailleur threaded right into the original metal hanger and the first iteration of the plastic one, right up until the c-shaped b-screw whatever-it-is got between them.

If you want to get into printing, I'd highly recommend it. Great for all sorts of projects and, if you have any CAD experience, it's 10x more powerful. Also, you win Halloween forever. Ender3 is probably the best entry level printer on the market, especially if you're not sure if you want to spend a whole lot of money on the hobby:


View: https://www.amazon.com/Integrated-Structure-Motherboard-Carborundum-8-66x8-66x9-84in/dp/B07FFTHMMN/ref=sr_1_3?keywords=ender3+v2&qid=1637335110&sr=8-3


"The snag with a plastic hanger is you cannot align it correctly (it won't bend and stay bent like an aluminum one would)
All hangers need to be aligned to a particular frame, you cannot just fit a new one and expect the mech to change cleanly. "

This snag never materialized. As I stated in the OP, the bike shifted better than it ever has and quite cleanly. Whatever mis-alignment was there, if there was any, was within the derailleur's tuning tolerances. You could bend plastic and expect it to stay bent but I wouldn't advise it. To be fair to your point, though, the reason I'm asking this question is making sure I have the hanger designed properly before I get one printed in metal (or a much harder plastic).
 
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