Hanger snapped again!

bikegangster

Previous thread about the first time: https://forum.bikeradar.com/discussion/13106969/replacement-hanger-for-giant-defy-2016#latest

Hello, my hanger snapped again. And i'm not happy. Its a new one as well only had it for four months. New derailleur, new chain and cassette, and new gear cable too. The accident happened yesterday, just two seconds after shifting the front chain ring to the 50 ring.

I don't know what caused it. There is a problem with gears skipping in the middle of the cassette which is already there. No skipping in the first few or last few, just the middle. Could the skipping gears itself caused my new hanger to commit suicide?

I wonder if its the gear cable housing from the barrel adjuster to the frame might be the causing poor shifting? The housing was damaged from the previous hanger snapping accident, and the damaged housing might had put friction on the cable making it harder to shift up or down smoothly, i dunno.

I also thought the derailleur itself maybe too small? Shimano 105 RD-5800 short cage 11 speed. Cassette is a 12-27 and chainring is at 34-50. No, why would a too small sized derailleur cause gear skipping?

Or the new parts I ordered were shit? Maybe the new hanger or derailleur is already bent before i installed it and I was unaware of it. Who knows.

Now the accident itself. The derailleur spun with the wheel and hit the chainstay. When i looked at the damage, there's plenty of chipped paintwork on the chain stay, brake cable housing is chipped as well. Thank goodness its a cable and not a hydraulic system otherwise I will expect leaking oil. The chain itself is damaged, one chain link is ripped off and trapped in the derailleur. Did the chain link rip off before or at the same time when the derailleur hit the chainstay?

Looking at those damages seriously annoyed me. The first time happened four months ago as detailed in the above link, it happened again just yesterday. I cannot be having the dumb ass derailleur snapping off the hanger, ride with the wheel spoke and be chipping away the chainstay, again and again. Or else I'll have to buy a new frame!

All I can think what to do is get a new hanger and certainly get a new gear cable housing. After that, see if the deraileur need to be replaced. I'll buy a medium cage just to be safe.

Sorry for a long read. What else could I do? Thank you!

pblakeney

What cog were you on the cassette?
Chain too short?
Trying to determine what would pull the derailleur so much. It isn’t simply indexing.

mugensi

Sounds like possibly the chain quick link failed, the chain kinked, caught in the RD and pulled it and the hanger off.

bikegangster

can't remember what cog i was on. It was somewhere in the middle, i think its between 5th and 7th gear when the hanger died. The chain length is fine. How I judge correct length is this: select the front ring on the 34 teeth and the cassette on the smallest cog, then put in enough chain until the derailleur cage (usually the bit where the upper jockey wheel is) is one chain length (or rivet, link or whatever its called) away from touching the slack at the bottom.

And no, I didn't use a quick link either.

pblakeney

If that’s your method then it is certainly too short.

pangolin

Surely you need to make sure there is just enough chain for you to be in the big ring up front and big ring at the back (not that you should be in that combo but... worst case if you are it doesn't rip your hanger off)

mtb-idle

how to determine ideal chain length here (see method two). it does sound like yours is too short

https://www.ilovebicycling.com/determine-bike-chain-length/

at least it's a simple fix and it's only the hanger that needs replacing ~(and a new, longer chain).

photonic69

After your first hanger broke and you replaced it did you check with a Hanger Alignment Tool that nothing was bent? If you were having less than optimal shifting as you said above with the middle range not sounding right then it seems that the setup/alignment was off.

Might be worth your time getting a LBS to check this after you have put a new hanger on or even getting them to do the whole job for you. At least you will know everything is OK and you might save money in the long run not having to buy derailleurs/chains/hangers and cable again!

pilot_pete

bikegangster said:

can't remember what cog i was on. It was somewhere in the middle, i think its between 5th and 7th gear when the hanger died. The chain length is fine. How I judge correct length is this: select the front ring on the 34 teeth and the cassette on the smallest cog, then put in enough chain until the derailleur cage (usually the bit where the upper jockey wheel is) is one chain length (or rivet, link or whatever its called) away from touching the slack at the bottom.

And no, I didn't use a quick link either.

You what? Where did you learn this method and please post a picture with the bike in the big ring and big cassette cog (before your hanger gave way). I’m intrigued...

PP

photonic69

pilot_pete said:

bikegangster said:

can't remember what cog i was on. It was somewhere in the middle, i think its between 5th and 7th gear when the hanger died. The chain length is fine. How I judge correct length is this: select the front ring on the 34 teeth and the cassette on the smallest cog, then put in enough chain until the derailleur cage (usually the bit where the upper jockey wheel is) is one chain length (or rivet, link or whatever its called) away from touching the slack at the bottom.

And no, I didn't use a quick link either.

You what? Where did you learn this method and please post a picture with the bike in the big ring and big cassette cog (before your hanger gave way). I’m intrigued...

PP

It sounds like more than enough slack. Any looser and the lower part of the chain would rub on the jockey wheel. Think of your derailleur position when in Small/Small combo. You don't want it so slack the cain rubs and bounces. Anyway, usual practice on standard chainsets is Big/Big plus a link PLUS a quick link.

pblakeney

PP was replying to the OP.
The OP sized the chain small ring to small cog, i.e. wrong.

photonic69

pblakeney said:

PP was replying to the OP.
The OP sized the chain small ring to small cog, i.e. wrong.

Yeah I realise that, but just think - you put your bike in Small/Small and you still need enough tension in the rear der. so your chain doesn’t sag and the der. fold up behind the cassette.

pblakeney

Yeah but all derailleurs are designed for that as long as your ratios are within spec. Any off the shelf bike will be.
Sizing small & small is asking for disaster. As evidenced.

i.bhamra

Reading the original thread it sounds like your new hanger needed aligning (a new hanger usually needs bending into correct alignment when fitted to your frame - the new hanger and/or the dropout on your frame will not be perfectly straight)- this was probably what was causing your skipping problem. As others have said the hanger snapping is most probably due to the chain being too short.

pilot_pete

To be honest it sounds like the op doesn’t really have the expertise to diagnose the problem. Looking to purchase new parts again, and this time a longer arm derailleur demonstrates that he is ‘pissing in the wind’ and is going to waste even more money if he doesn’t get to the root cause of the problem.

It could be chain length. It could be split link/ joining pin if not fitted correctly catching on the cage, it could be a bent chain link, it could be a mis-aligned hanger, it could be a worn jockey wheel, or a number of other possible causes.

After one such bad experience when you have done it yourself, if you really don’t know why it happened it may be wise to take it to a qualified mechanic and have them sort it out.

PP

bikegangster

Update:

Still waiting for a new hanger to arrive. I hate wating! I can't do nothing for now. I can just measure out the chain and make sure its correct. And get new cable housing for the derailleur. I won't buy a new derailleur just yet.

Checking this link as provided by someone else. https://www.ilovebicycling.com/determine-bike-chain-length/

Using method three, the equation way: L = 2 (C) + (F/4 + R/4 + 1)

Chain stay length is 16.5 inches, front chain ring is 50, rear cog is 27. After working out the equation, I got 53 inches. The chain length at the time of accident was 55 inches. So It's two inches too long. Unless I did the equation wrong. I hope my maths is correct! I hate maths.

photonic69

This:
https://www.parktool.com/blog/repair-help/chain-length-sizing

Or what people usually do Big/Big and add two links.

I don’t think your chain length caused your problem, more like hanger misalignment.

lesfirth

I just do not see the need for these different chain measuring methods.
The only thing your chain HAS to be is long enough in big front and big rear. If it is not you will have a disaster if it is too long in small front and small rear nothing serious happens and there is no need to use that combination.
As above big/big ( without going thru the rear derailleur) and add two links.
However I don't think chain length is the OPs problem.

wongataa

Why don't people just size the chain the way the manufacturers of their gear systems say to do it in the instructions? It is a lot less complicated than random maths and it works.

thecycleclinic

If this has happened twice I would advise the op to visit a good shop and let them set it up. Since you dont know the cause of the issue and none of us here do as we have not seen your bike any advise we can offer is limited. You may set it up right this time or you may not. Given the last time it did not run right in the middle sprockets and you dont know why, this means you are overlooking things that would need addressing.

The mech hanger broke because for some reason your chain jammed a d you continued to apply pressure. If you rode enough eventually this happens to you (it's happened to me a few times on one bike witha 11 speed chain and 10 speed chainset when down shifting and the chain just jams and gets caught up around the inner ring) but what I dont do is continue to apply power. When changing rings or rear sprockets you back of the effort. This makes the changes smoother and if there is a mishap you can stop pedalling immediately, co.e to stop and sort it out.

So theres two things that need addressing here. The chain jam issue and your finesse when changing gear. That may sound harsh but the mech did not rip off by it self. The chain jam is not the sole cause. It has to be a jam and continued pedal pressure to cause the mishap.

pblakeney

thecycleclinic said:

...but what I dont do is continue to apply power. When changing rings or rear sprockets you back of the effort. This makes the changes smoother and if there is a mishap you can stop pedalling immediately, co.e to stop and sort it out...

True dat. Old skool guys learned that way as it was the only way. Old habits die hard. Pity that the marketing these days says otherwise.

thecycleclinic

I'm not old enough to be old school.

pilot_pete

Yeah, I still back off the power when shifting using di2! I remember when it first came out I had mates telling me the beauty of it was you could change gear under full power. Made me wince then and still does now after several years of using it and still not thinking it a good idea!

PP

darkhairedlord

bikegangster said:

Previous thread about the first time: https://forum.bikeradar.com/discussion/13106969/replacement-hanger-for-giant-defy-2016#latest

Shimano 105 RD-5800 short cage 11 speed. Cassette is a 12-27 and chainring is at 34-50.

there's the problem, right there.
12-27 cassette is a 10 speed.

darkhairedlord

"B" screw not adjusted correctly and causing the cage to snag on the cassette.