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Not one, but TWO] snapped front derailleurs--WTF?

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Not one, but TWO] snapped front derailleurs--WTF?

Old 08-17-13, 04:11 PM
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rousseau
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Not one, but TWO] snapped front derailleurs--WTF?

Jayzus, what the aitch is going on here?





The Centaur arm snapped last year in mid-shift. Just today the Chorus arm cracked as I was tightening the cable, then broke off completely. I'm peeved.

Last edited by rousseau; 08-17-13 at 04:17 PM. Reason: Wording
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Old 08-17-13, 04:13 PM
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Weak ass campy ****e
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Old 08-17-13, 04:17 PM
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Originally Posted by pdedes View Post
Weak ass campy ****e
Speaking of which, you got a spare you can sell me? I'm just down the road. Heh heh...
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Old 08-17-13, 04:24 PM
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Ouch.
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Old 08-17-13, 05:32 PM
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Torque wrench broken?
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Old 08-17-13, 06:08 PM
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Inadvertent double post.

Last edited by rousseau; 08-17-13 at 07:54 PM.
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Old 08-17-13, 06:09 PM
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Originally Posted by NWS Apline
Torque wrench broken?
Yeah. What? No. No, I don't have a freakin' torque wrench to tighten the cable on my front derailleur. Who does? I wasn't reefing on it, I just tightened it like I normally do.
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Old 08-17-13, 07:12 PM
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Originally Posted by rousseau View Post
Speaking of which, you got a spare you can sell me? I'm just down the road. Heh heh...
Can't help you, sorry. That is some hard luck right there.
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Old 08-18-13, 07:54 AM
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Originally Posted by rousseau View Post
Yeah. What? No. No, I don't have a freakin' torque wrench to tighten the cable on my front derailleur. Who does? I wasn't reefing on it, I just tightened it like I normally do.
I was being sarcastic. I would't use one for the cable stop either.
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Old 08-18-13, 08:18 AM
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You really need to review what you are doing before blaming the part.
My Campy Chorus band on front d is 14 years old and has worked flawlessly since I first installed it in '99.
How did they break? What were you doing before/when they broke? Were they new or used? Were they damaged before you installed them?
Possibly trying to shift under a very heavy load may possibly break the top of the arm off but I've never seen it happen before in 20 years of working in a lbs.
The Chorus d looks quite pitted at the band area and the break looks like a lot of torque was placed on the fixing bolt/area that secures the cable. Normally, and I've seen this a few times, the threads on the d are stripped as they are aluminum and the bolt is steel...the normal fix is to use a nut and bolt...works quite well in fact but adjusting the cable is a bit more difficult.

Give us a better description of what happened if you aren't just griping.
It is certainly not just because it is Campy...I still see Nouvo Record stuff, not much, on the road.
Without more info I'd say user error...
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Old 08-18-13, 08:38 AM
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Originally Posted by rousseau View Post
Yeah. What? No. No, I don't have a freakin' torque wrench to tighten the cable on my front derailleur. Who does? I wasn't reefing on it, I just tightened it like I normally do.
And it looks like you normally break them...

Campagnolo used this same outside arm design on all 8, 9, and 10spd front derailleurs and these are the only broken ones I have ever seen. I don't want to accuse you of anything, but I would recommend using a torque wrench (campy has a torque spec for every bolt) and seeing if things change. I've owned and wrenched a lot of these with no issue.
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Old 08-18-13, 08:44 AM
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First (and second) time I've ever seen that happen, and I've seen a LOT of broken parts.
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Old 08-18-13, 08:48 AM
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Originally Posted by cxwrench View Post
First (and second) time I've ever seen that happen, and I've seen a LOT of broken parts.
Exactly...

I looked up the torque spec in the Campagnolo manual, it is 5Nm.
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Old 08-18-13, 09:05 AM
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I would think over-torquing would result in stripped threads, or snapping the screw head off, not breaking the arm.
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Old 08-18-13, 09:10 AM
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Originally Posted by pdedes View Post
Weak ass campy ****e
Ive had 2 105 triple front D's break when the catch for the spring broke. These are the only fd breaks I've ever had. Sometimes bad luck does strike twice.

I'd call this unlucky and carry on. Talking about precision torque and all that is going a bit far, just tighten the bolt until you meet resistance.
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Old 08-18-13, 09:15 AM
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Originally Posted by Homebrew01 View Post
I would think over-torquing would result in stripped threads, or snapping the screw head off, not breaking the arm.
I wouldn't think it would cause the centaur failure, but I could see it cracking like the chorus. After all, it did happen when it was tightened. The bolt is steel and the derailleur has a steel insert. both should easily hold much more than 5Nm. Maybe the steel insert is breaking free from the alloy arm. maybe the centaur arm cracked when tightening and then shift pressure caused the crack to go down the arm. If it did, there would be a crack coming off the bolt hole.

whatever happened, it seems to be unique to the OP and one failure was confirmed in the stand so I'm skeptical it is an issue with the bike itself.

Originally Posted by Leinster View Post
Ive had 2 105 triple front D's break when the catch for the spring broke. These are the only fd breaks I've ever had. Sometimes bad luck does strike twice.
This particular failure seems fairly common. I just replaced a sora for a coworker that had the same issue. Ive seen a number of shimanos fail this way.

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Old 08-18-13, 09:55 AM
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It's Campy's way of telling you to upgrade to 11 speed. Then you can get this kind of failure:

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Old 08-18-13, 10:08 AM
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A long time ago, I cracked a rear derailleur coz i did up the cable clamp too hard.
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Old 08-18-13, 11:56 AM
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Originally Posted by thirdgenbird View Post
I wouldn't think it would cause the centaur failure, but I could see it cracking like the chorus. After all, it did happen when it was tightened. The bolt is steel and the derailleur has a steel insert. both should easily hold much more than 5Nm. Maybe the steel insert is breaking free from the alloy arm. maybe the centaur arm cracked when tightening and then shift pressure caused the crack to go down the arm. If it did, there would be a crack coming off the bolt hole.

whatever happened, it seems to be unique to the OP and one failure was confirmed in the stand so I'm skeptical it is an issue with the bike itself.



This particular failure seems fairly common. I just replaced a sora for a coworker that had the same issue. Ive seen a number of shimanos fail this way.
Agree on the Centaur vs Chorus failure modes. The Centaur could only be by too much bending moment. I've had FDs that are just a flat plate in that position, so that design should never just snap like that.


On the Shimano, yeah, it was just a small catch that failed both times; part of the problem might have been that I was keeping the bike in an outdoor car port near the sea for 2 years, but I can easily see how it would happen again and again.
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