4 snapped rear hangers

anthdci

I have a 2013 giant defy 1, which has the 105 groupset. I have had it about 4-5 months now and it has broke 4 rear derailleur hangers, that's right 4! Now I know this part is designed to break so to prevent damage to the frame or derailleur however I feel this is excessive so there is clearly something causing this. After the first one the chain was changed, after the second one demolished the derailleur that had to be replaced. After the 3rd I replaced both chain derailleur and cassette. So that is every part of the drive chain excluding the front derailleur and chainset. This morning the 4th hanger snapped about 1 mile into its first use. The first 2 changes were done in the LBS that I bought it from, they charged me for a new derailleur and hanger the second time blaming me for causing it. So I changed it myself the 3rd time. I was advised it could be the chain length, so the new one was measured up correctly, it wasn't too long or too short.

So all that rules out issues with,
chain
cassette
rear derailleur
workmanship

I have rang my local Giant shop, which is in York about 150 miles away to see if they can advise, I am waiting on them getting back to me but I thought I'd post to see if anyone on here had any ideas, what could be the cause.

The LBS haven't been that helpful. They sorted it the first time it snapped for free, but I've been hit with a bill for £70 for the second time, which is why I didn't take it to be changed by them again. I rang them for advise and they said bring it in but there will be a charge, and blamed where I store the bike, (in my front passageway) and how I ride it, but I rode my Specialized Tricross for more miles and had no issues with that.

I haven't had time to look at this morning damage since i had to push the bike back home then go for the train to work, but I think the derailleur is ruined again.

I am at my whits end with it, I cant afford to be buying the same parts again this close to Christmas.

topdude

I would have that bike on a workstand and have someone turn the cranks and change gear while watching what goes on at the back end. Something is definitely wrong !!!
Is the mech hitting the spokes,
Is the chain catching on the jockey wheel cage somehow,
Is there a mis-alignment with the wheel / frame,
Is the Chainline wrong,
Did it happen in the same gear each time,
Were you pedalling hard each time,
So many questions !!

cycleclinic

This should not be a bike specific issue. You are right there will be a reason but without anyone seeing the bike it is not possible to diagnose og tinterweb. The reason could be mechanical or it could rider related or both.

You do need to see what is happening in the stand once a new hanger is fitted. If you are passing suffolk I woud have a look for no charge other than that try a different LBS or learn how to fix stuff yourself.

Monty Dog

I would suspect there's something wrong with way the gears are set-up as topdude identifies above or if you are overloading the drivetrain e.g. trying to shift to the biggest sprocket on the big chainring which is pulling the rear mech into the cassette. The gear hanger is designed to break when the drivetrain is overloaded - they very rarely fail of their own volition.

anthdci

Is the mech hitting the spokes, - No, checked it on my workstand when i installed the last one, clean and clear shifting to all 20 combinations

Is the chain catching on the jockey wheel cage somehow, - Didn't seem to be

Is there a mis-alignment with the wheel / frame, - wheel was seated in the frame correctly. It has happened on two different wheelsets now.

Is the Chainline wrong, - what does this mean?

Did it happen in the same gear each time, - not the same gear but always on the big chainring, (since i nearly always use that)

Were you pedalling hard each time, - I have never been going particularly fast, probably about 12mph would be an average between each time. It has been when speeding up from a junction 3 times, (where i have just slowed but not stopped) and once from stationary at a set of light. I didn't shift when it happened.

montydog - how would i pull the rear mech into the cassette, surely the way it is bolted on would prevent this. I cant test this now as the mech is hanging off. I am going to wait on giant getting back to me before buying anymore parts so when i do get it fixed back on I'll see if it is possible.

topdude

My guess from the extra info you provided,

Running on large chainring, pulling away from junction, probably on one of the larger sprockets on the cassette ?
Chain crossing at too sharp an angle, chain catches on bottom of cage and breaks off the mech ?
Could be due to chainline (centreline of chainrings too far out from centreline of frame).

Complete guess of course but it could be down to how you are riding and not failure of components or setup.

slowbike

The mech will only break when under too much load - as a free running chain provides very little load then it is either the dérailleur hitting the spokes (which you've ruled out) or something causing the chain to snag.

Obvious answer for you - without having to do anything - is to not pull away in the big ring.
More complex answer would be to check that everything aligns correctly when you're in the big ring on the front and the big ring on the back - there will be some cross chaining, but it should run without snagging on anything. Check that the chain isn't too taught too ...

Cross chaining isn't a good idea - but the bike shouldn't break whilst doing it ...

anthdci

@ topdue I will get a replacement fitted and see what it looks like. Surely I am not the only person with a defy that pulls away with the chain on the large chain ring. I cant believe a component would be so weak that it will break under what is to me, normal use, ie starting away from a junction with the chain in ratio that is not too easy and not to hard to move.

@Slowbike yea using the small chainring is an option that may solve it, but isn't it a work around? I would rather a proper solution.

crankycrank

I wonder if the mechanics checked the alignment with the new hanger mounted. Some less competent types will just assume a new hanger does not need checking. It's always hard to diagnose and find fault over the net without photos and knowing the whole story but I would try a different shop. This should be an easy fix for a good mechanic who after the first break should have done a thorough check to make sure everything was setup and functioning properly but again, it's impossible to say for sure if it's the mechanics fault or ?? Unless you're banging your rear mech against something when you store it there shouldn't be anything in your riding habits that would cause this.

anthdci

Old thread, but I thought I should let everyone know the fault in case it happens to them. The faulty part was the rear wheel. I found this out after snapping a spoke on the drive side. I took it in for a new spoke and they said that it really needs rebuilding, the drive side was as tight as the spokes would go, and the none drive side was slack. But tighten the none-drive side up and it would pull the rim to foul the frame. Because the none drive side was slack, when i got up out of the saddle and the chain was on the largest rear sprocket, then leaning the bike left and right was offsetting the rim pushing it into the derailleur. 3 replacement derailleurs, 4 chains, 4 rear hangers later, I have put my fulcrum wheels on and it has been absolutely fine. 2 local bike shops were unable to diagnose this before the spoke snapped.

cycleclinic

If the wheel was out of dish then the shop could have spotted the problem but if not then it not the first thing that springs to mind. Also getting up out of the saddle and rocking the bike and getting wheel flex just means the wheels are not stiff enough for your riding style that is ot the LBS's fault. If the NDS spokes were really slack then the wheel would have fallen apart very quickly so I think for wheel builder means there is low tension on the NDS spoke which is not a problem if the rim is stiff enough (it may not be), the hubs give a good bracing angle (they may not), the spoke count is high enough and the spokes are stiff enough. If the components used in the wheel build do not suit the rider then a flexible wheel may result giving the problem you have encountered again not the LBS fault. In fact rebuilding those wheels will not solve the problem. Switching to your fulcrum did because it is a stiffer wheel.

This may seem technical but I do not think the LBS which tried to fix the problem is at fault for what you have said.

I am sorry to say but the wheels combined with your riding style was the problem they were not matched. If you just sat down and pedalled which i what I do (standing up does make me go faster) you may not have broken a hanger.

slowbike

anthdci wrote:

Old thread, but I thought I should let everyone know the fault in case it happens to them. The faulty part was the rear wheel. I found this out after snapping a spoke on the drive side. I took it in for a new spoke and they said that it really needs rebuilding, the drive side was as tight as the spokes would go, and the none drive side was slack. But tighten the none-drive side up and it would pull the rim to foul the frame. Because the none drive side was slack, when i got up out of the saddle and the chain was on the largest rear sprocket, then leaning the bike left and right was offsetting the rim pushing it into the derailleur. 3 replacement derailleurs, 4 chains, 4 rear hangers later, I have put my fulcrum wheels on and it has been absolutely fine. 2 local bike shops were unable to diagnose this before the spoke snapped.

You said you tried it with two different wheelsets - were they the same make/model?

Anyway - which wheelset was this?

anthdci

well the NDS spokes were finger tight in the nipples, it was that they could not be put under any tension or it would go out of alignment, or so the guy at the bike shop near my work told me. The wheel in question was the standard wheel that came with my defy 1.

The two different wheelsets were both the same standard wheels that came with the bike, the shop I had bought it from had replaced it due them not being able to true the original when it went in for a service / replacement hanger/derailleur. They assured me the wheel was not the cause at the time. Clearly they were wrong and have a poor wheel builder!

dj58

Is the wheel in question a Giant P-R2 28H with 14/15g Sapim Race spokes laced 2X DS, Radial NDS?

anthdci

DJ58 wrote:

Is the wheel in question a Giant P-R2 28H with 14/15g Sapim Race spokes laced 2X DS, Radial NDS?

Sounds right to me. The guy in the shop who replaced the spoke for me said it is most likely an unbrandad hub, with cheap rim and spokes then Giant stick their branding on.

dj58

For someone who works in the cycle trade the guy who dealt with you doesn't seem to known much about the bikes he is selling. According to the info I can find on the subject the hubs are Giants own designed with input from DT Swiss, spokes are Sapim a well known brand, I don't know about the rim though.

If the first wheel was faulty (not tensioned correctly), when the bike was new, that should have been picked up at the P.D.I. You seem to have been unlucky in that the replacement wheel was also faulty, did it unwind after the first ride or was it like that when you collected the bike? I would have thought that the shop would have double checked the replacement wheel was fault free.

If the faults were caused by poor build/quality control at the factory, then I think you might have a claim for your out of pocket costs with Giant. The thing is you can't contact Giant directly through their website/telephone to raise issues like this, as they direct you to the selling dealer/shop. So depending on how good they are or what your relationship is like with them, it could be a pain to resolve.

Thanks for coming back to your post and lettings us know the outcome bye the way.