Baffled; second derailleur hangar to snap this year

[Fifelad]

As we all know, the hangar is meant to shear if it is hit against a hard surface, the weird thing is, on two different occasions this year my hangar has went for no apparent reason. Today, while changing gear before going up a hill I looked down and it had sheared. The bike has never been dropped hard on the derailleur side to have caused that. Baffled.

 

[Gillstay]

Perhaps there is a bad batch of hangers going around and you have been unlucky.

 

[Fifelad]

Perhaps for the second time. The first time, the hanger had been on the bike from new, it’s 8 years old.

 

[cougie uk]

Did you ease off the power as you changed gear?

 

[ColinJ]

Is the endstop adjusted properly? If not, perhaps the derailleur is going into your spokes...

Or is the chain too short and you changed to big-big?

 

[HLaB]

As we all know, the hangar is meant to shear if it is hit against a hard surface, the weird thing is, on two different occasions this year my hangar has went for no apparent reason. Today, while changing gear before going up a hill I looked down and it had sheared. The bike has never been dropped hard on the derailleur side to have caused that. Baffled.

I've had one deraileur hanger snap in all my time of cycling, it was when I was in Fife and touchwood the only things which have went majorly wrong with my bikes is up there. I just think the Scottish roads are harder on components.

 

[Ajax Bay]

Carry a spare with you all the time, with that quality of 'luck'.

 

[Fifelad]

Chain is definitely not too short; gears have been changing perfectly, definitely no incidents of the derailleur over shifting to the spokes.

 

[DCBassman]

The only other thing I can think of is that you're putting down awesome amounts of power, but I'd imagine something else would break first if that were the case!

 

[Dogtrousers]

And this is the second derailleur hanger broken thread on here in about a week.

There's something going on ...

 

[Fifelad]

There seems to be a plausible explanation after a post mortem at the LBS. It would appear that a jockey wheel with a bit of excess play in it has allowed the chain to slip off when changing gear and get jammed between the mech and plate and in turn has yanked the mech over and the the resulting hanger snap. Mech plate bent on one side ( the side you can’t replace separately) A sore one, but hey ho that’s life. LBS as usual were very good. A new Ultegra mech and only charged for the price of a 105, as it had been on the shelf for a while. New chain despite LBS best efforts at straightening it out.

 

[bikingdad90]

Sorry to hear of your bad luck @Fifelad, I was going to suggest some unscrupulous person not taking care when locking your bike up next to yours when leaving it unattended causing the mech hanger to bend and then eventually snap.

 

[andrew_s]

There seems to be a plausible explanation after a post mortem at the LBS. It would appear that a jockey wheel with a bit of excess play in it has allowed the chain to slip off when changing gear and get jammed between the mech and plate and in turn has yanked the mech over and the the resulting hanger snap. Mech plate bent on one side ( the side you can’t replace separately).

It's good that the cause has been identified - you now know to replace the jockey wheels occasionally, before they get too bad :-