This is the Campagnolo mess when your rear gear hanger breaks

[Alexandrumarian]

Maybe those plastic dishes would be useful after all?

[mattr]

Not if its the chain jamming in the rear mech. Once that gets going the spoke protector isn't going to do anything except add to the chaos.

[c60rider]

With this there was no warning at all that anything was amiss until the wheel got jammed up. My suspicion that it was just a failure of the gear hanger alone for no other obvious reason, in that everything happened so silently. If it had just failed then as the wheel slowly rolled round after pushing off this would not have been apparent as I was freewheeling ready to clip in my standing leg. As I clipped in and just pressed on the pedal the chain would pull the rear mech round with the cassette until the cable pulled tight and caused it to twist into the rear wheel. This is why almost the instant I clipped in and started to pedal I came to a grinding halt as the wheel would have had only half a revolution to travel to get it into the position you see in the first picture. I'm sure some do fail due to poor adjustment or the chain just unseating somewhere and getting jammed in with the rear mech but none of that happened in this case. The exact cause will never be known but it was all very innocuous

[bm0p700f]

well that really unlucky then. Forced bike change. Console your self in selecting a new bike. The king is dead long live the king...

[Karvalo]

With this there was no warning at all that anything was amiss until the wheel got jammed up. My suspicion that it was just a failure of the gear hanger alone for no other obvious reason, in that everything happened so silently. If it had just failed then as the wheel slowly rolled round after pushing off this would not have been apparent as I was freewheeling ready to clip in my standing leg. As I clipped in and just pressed on the pedal the chain would pull the rear mech round with the cassette until the cable pulled tight and caused it to twist into the rear wheel.

Yeah, but then how did the dropout get smashed?

[mattr]

What he said^^^^.
It's not just failure of the hanger. Or the mech would have just dropped off and dangled there, no load on the frame.
I reckon the chains got jammed.

[c60rider]

With this there was no warning at all that anything was amiss until the wheel got jammed up. My suspicion that it was just a failure of the gear hanger alone for no other obvious reason, in that everything happened so silently. If it had just failed then as the wheel slowly rolled round after pushing off this would not have been apparent as I was freewheeling ready to clip in my standing leg. As I clipped in and just pressed on the pedal the chain would pull the rear mech round with the cassette until the cable pulled tight and caused it to twist into the rear wheel.

Yeah, but then how did the dropout get smashed?

I wouldn't call it smashed particularly, the lower edge of it has just torn off. The gear hanger sits within the rear dropout and that's where it's gone. Abnormal forces on modern equipment seems to break it easily these days but that's the price to pay for the lightweight bikes we now have.

[c60rider]

What he said^^^^.
It's not just failure of the hanger. Or the mech would have just dropped off and dangled there, no load on the frame.
I reckon the chains got jammed.

I wish people would stop being such experts and know what happened. I posted this purely for people to see what can happen when one does break and there isn't always a clear reason how or why that happened. Nobody will know how it happened and it doesn't really matter but there was nothing abnormal that occurred prior to it. I was on a main road, pulled into the centre filter to turn right and had to stop, so left foot down, no gear changes prior to this, nothing untoward at all. Brief bit of pressure to get moving, freewheeled for a moment as I clipped in, pushed the pedal round a fraction and came to an instant halt.

[Karvalo]

I wouldn't call it smashed particularly, the lower edge of it has just torn off. The gear hanger sits within the rear dropout and that's where it's gone. Abnormal forces on modern equipment seems to break it easily these days but that's the price to pay for the lightweight bikes we now have.

Exactly - if it breaks on its own under normal load where does the abnormal force on the dropout come from?

[Calnago]

You're right that no one can know for certain, but a lot of folks here are very mechancically minded (myself included) and always like to try and figure out the cause of why something happened, it helps in diagnosing future problems and ensuring they don't happen in the first place. I don't think anyone is trying to accuse you of doing anything wrong at all, it's just an interesting case to look at collectively and learn from. Mattr correctly pointed out that even if the derailleur hanger screws were loose, the skewer would likely be holding it well enough to keep it aligned as it should be. And Karvalo I think correctly implied that if the hanger had been weak and just broke on it's own, then it wouldn't have taken out the dropout along with it. And I still don't know how the chain could end up so perfectly wrapped around the largest cog. But you're right, we won't know for sure, but thanks for posting anyway.

[bm0p700f]

I had my chain jam around the chainrings before, not sure why and the mech pulled forward alit. Fortunately as I was changing chainrings I was able stop pedalling. That allowed me to free the chain and avoid what happened to c60rider. If your spinning at 90rpm it would be harder to avoid. In my case the problem has gone away even though I have not changed the chainrings.

My guess is something like this has happened.

[LouisN]

Sorry to hear this. I had a similar thing happen to me a few years ago.
The RD ( not Campy though... ) went all the way around the cassette and broke my rear seat stay:

(I'm still riding the repaired frameset today )
My opinion is your derailleur cage got caught in the spokes, then everything (including the hanger) ripped apart.
I don't see how you can crack open a dropout like this if the hanger snapped first.
Maybe frameset defect, the crack was there already and the situation just waiting to happen....
FWIW a junior rider I know ripped his RD and cracked his dropout on a crash in a race. His mother was pretty sad seeing his Supersix EVO was ''done''. I sent her to a local carbon repair shop. She paid $400. and he still rides his EVO two years after the crash.


Louis

[c60rider]

Sorry to hear this. I had a similar thing happen to me a few years ago.
The RD ( not Campy though... ) went all the way around the cassette and broke my rear seat stay:

(I'm still riding the repaired frameset today )
My opinion is your derailleur cage got caught in the spokes, then everything (including the hanger) ripped apart.
I don't see how you can crack open a dropout like this if the hanger snapped first.
Maybe frameset defect, the crack was there already and the situation just waiting to happen....
FWIW a junior rider I know ripped his RD and cracked his dropout on a crash in a race. His mother was pretty sad seeing his Supersix EVO was ''done''. I sent her to a local carbon repair shop. She paid $400. and he still rides his EVO two years after the crash.


Louis

As I've mentioned previously the chain was in the middle of the cassette and there were no gear changes involved. It just ended up like that in the picture. The fact it appears perfectly wrapped around the largest sprocket is just a coincidence. The item that caused everything to grind to a halt is actually the gear cable which is testament perhaps to the strength of them.

[kode54]

I had a Campy SR11 rear mech do the same thing. But here's what transpired...

I was riding in the fall where there are leaves on the side of the road. I got close to a pile making a turn and believe it or not, a branch flicked up and went into my spokes and I crashed mid-turn. I pick myself up and the bike...all seemed good. I didn't thouroghly inspect the rear mech, so after brushing off the dried leaves, I started to ride back home. Well, half way home, my rear wheel locked up and looked similar to yours with the chain wrapped up with the hanger torn off, broken RD, and marks on the spokes.

So yes, it originated from my initial crash, which wasn't all that bad since I was able to get up and ride back towards home. The rear derailleur broke due to a possible crack in the parallelogram, thus, causing an avalanche of damage.Took me by surprise.

[c60rider]

Thought I would update on this one as I may have discovered a reason for the failure. The only reason I had changed the rear gear hanger last year was due to the original coming loose after being in the frame for 7 years. As I still had the original I put that back on and the damage to the frame wasn't actually that bad. The dropout was only scuffed at the bottom edge, aside from the crack that can be seen. So I decided to turn this into an indoor bike only and purchased a new rear mech. On installing everything, and I'm using this since I purchased it with a Sram red quarq power meter, it was pretty much unusable in the small chainring with it sounding like a bag of nails grinding round in a washing machine. On reading around it pointed to a worn inner chainring so I've purchased a new one and it's working perfectly. So this is the only thing it could possibly be as I was in the small chainring at the time of the failure. It's the only non-Campagnolo chainset I've got and I've never worn a chainring out previously and I have chainsets with many more miles and much older than the Sram which is a bit disappointing. So in the absence of anything else it must have been that.