CaptainPlanet

This is probably a very simple question, but I haven't had a bike with rear derailleur hangers until now.

I haven't taken a thorough look at this, just broke the rear derailleur hanger and am panicking not sure whether it will damage the frame somehow.

The 2 extruded piece from the hanger which goes into the mounting holes on the frame had broken off from the hanger and stuck inside the frame. How do you remove them? Do you just push them out with a screw driver? Will that hurt the frame? Or is there some kind of threading involved?

Andrew R Stewart 

Those two pieces are likely small steel bolts, not extruded parts. have you removed the wheel and tried to then remove the hanger from the drop out? It looks to my late night eyes that the bolts' heads broke off and the the remaining stubs won't hinder the hanger's removal. Whether the bolts can be then removed from the hanger and whether you can find replacements would be the next step.

It also looks like the der might have gotten pulled back so far it hit the drop out on the back side. Did it get tangled up in the spokes? Andy

CaptainPlanet

Those 2 pieces have actually broken off the derailleur hanger, and is just stuck inside he frame. Right now the hanger is actually just held there by the wheel release.

tFUnK

So, I guess your question is whether the threads in those holes are stripped when the outer piece of the hanger broker off?

dsaul

As Andy said, those two holes are for the bolts that hold the hanger onto the frame. Without knowing what bike it is, its hard to tell exactly which direction it was bolted from. The holes in the frame appear as if they are recessed for the bolt head and the bolts thread into the hanger. Maybe a pic of the hanger and the frame part separately would help us advise you on how to proceed. I will note that both Andy and myself build frames and are familiar with the various ways in which these hangers are attached and it is always a bolt of some sort.

dsbrantjr

If those are bolt stubs left in threaded holes it should be a simple matter to drill them out, they will likely turn out from the back side when you start drilling, provided the holes are tapped through; blind holes are unlikely in a thin part.

dabac

Functionally, those aren’t required. Their main purpose is to hold the hanger in place when the wheel is removed.
Take the RD off, take the wheel out, take the hanger off. Explore how hard they’re stuck. If the broken bits won’t come out with reasonable coaxing, feel fred to reassemble, ride while you hunt for replacement at your leisure.

Andrew R Stewart 

It's quite understandable that the OP is both unfamiliar with how his bike is designed as well as hesitant to start taking stuff apart. So perhaps viewing this problem from a different angle will shed some light.

https://derailleurhanger.com/ is an on line source for many (as in the hundreds these days) of the hangers different brands and models use. One can search by brand and model of bike or by the number of fasteners, two in the op's case. More to the point I am making is that one can see how the hanger is shaped and fastened to the drop out better without removing it. One will also see that pretty much all the hangers are screwed or bolted on by some small fastener, other then the big one (the axle).

One will see that there are many subtle contour and fastener designs, know that only one is likely to be the correct one. We get this question every week at the shop. "Which one do I need" Since bike brands change this stuff w/o any notification (a Trek Madone bought in 2007 could have one of two different hangers as example). We rely on having the OEM one in hand before we spend our $ to order the correct one for the customer. In other words at some point before confirming the correct hanger the old one needs to be removed.

I alluded to the possibility that the problem came from the der becoming tangled up in the wheel spokes or otherwise yanked back and up rather hard. The small white spot at about 8:00 WRT the axle suggests some paint removal from the der's top knuckle. If this did happen expect some secondary damage like a twisted der cage WRT the cogs, twisted chain link(S), spoke(s) with a slight kink now, the der's "B" screw or the tiny tab it threads into could be bent. I strongly suggest the someone with experience takes a look at the overall situation before $ is spent. A decent bike shop will assess the repair for free, and if they do but the OP wishes to try the repair themselves then source the hanger from that shop as the least. Andy

tomtomtom123

You can also buy cheaper hangers with the union marwi brand. They use the cheaper manufacturing method in mass production. I don't remember the method, casting? The wheelsmfg versions are more expensive because they are CNC, small volume, and made in the USA. I found the union hanger for my bike for $4 from a local seller.
Type
https://www.marwi-eu.com/gh_assembly_style.php
Bike model
https://www.marwi-eu.com/gh-bike-model-lists.php
If you click on the thumbnail and scroll through the photos then you'll find the PDF download link for the 1:1 scale print of the hanger.
Oh I just looked at the company profile page and it says production is in Indonesia, Taiwan, Czech Republic and USA. Might be why they're so easily found locally. Claims to be designed in Germany. Looks like a Taiwanese company.

CaptainPlanet

Ok it looks like I had everything all wrong. There was never a single screw in the derailleur hanger in the first place. The hanger was just held in place by the quick release and some kind of glue. The screw holes were empty. It fell off because I was redoing the tires.

I got a second hand Brodie Sterling first gen for cheap (under 100), but it's all weird. The wheel quick release had been swapped with the seat tube quick release, and both wheels didn't have the quick release pressed in, they just screwed in and didn't flip the release handle. The adjustable seat post lost its cover, and the disc brakes are not working properly. The tires have cracks on them. And I am still finding new problems as I examine the bike.

The owner just left it in the patio and didn't give a crap about it until now.

I still feel like it's a good buy, but it will take some work to get it road-safe.

cobba

Looks like 2 x M3x8 Flat Head Screws are probably needed to attach the hanger.

https://wheelsmfg.com/derailleur-han...anger-154.html

Andrew R Stewart 

Sounds like the entire bike would benefit by a competent going over. Where there's smoke fire can be near by. Andy