Ever see a front derailleur break like this?
 

http://im1.shutterfly.com/media/47b9...D720/ry%3D480/

Last time I rode, it was shifting fine. This morning -- well, that happened. The bike has never been crashed. The clamp-bolt was torqued to spec. That was a 10-speed Campy Chorus derailleur; it had seen about 5000 miles of service. Just seems like a very unlikely place for it to break; if it had been a manufacturing defect of some sort, I wouldn't have though it would take 5000 miles to show up.

A friend's Campag front mech broke in just about the same location last month. It was an 8 sp triple though and had done a lot more than 8000 km.

Too much torque used when installing? Those are alloy, and don't hold up as well as steel. Less forgiving to exceeding maximum torque than steel would be. On a positive note, the actual front-derailleur (FD) seems to be fine. I don't know if a replacement for the band is available. So you may be stuck with getting a new FD - but call, or drop by, your LBS and see if they have something that will work in a parts-box somewhere.

A torque-wrench and installation instructions would help you in the future.

I had a Suntour (Cyclone, I think) break just like that after maybe a decade of use. I don't _think_ it was over-torqued.

I'd send this pic to Campy.

Be polite about it, they may offer you a replacement.

:cheers:

I use a torque wrench (Craftsman) for everything. This isn't the only FD I've installed; the others are working fine.

Garthr seems to have the best suggestion.

Agreed! :thumb:

Heck, if all else failed, I'd drive that roll pin out and make a new clamp out of stainless. It doesn't look like it would be too much difficulty, as it is a single curve piece. Could be done. But I'm just a stickler for fixing things.
I'm seeing WAY too much of this kind of things nowadays....things breaking way too soon. And many times too expensive to fix....just buy another! Well, not me if - I can help it!

Sure:

http://os2.dhs.org/~john/huret-fd.jpeg

In the never-ending attempt to lighten parts, they are made more and more minimally to just about bear the loads inflicted upon them. More heft at stress points means more weight. All kinds of alloys are used for two reasons; one they are light and two, they are cheap. Bolts, brackets, wheels, etc. We keep chasing light weight and the manufacturers keep making items lighter. Any type of stress put on a part from a differing direction could break a part. I have seen broken bars, cranks, derailleurs, etc. A racing bike is like a finely tuned watch, pretty, useful and fragile.