Originally Posted by wgscott

Di2 has a crash-protection mechanism whereby you have to reset the derailleur after impact, to prevent a disaster if (for example) the hanger is bent enough to send it into the spokes when shifting to the lowest gear. There is a simple reset procedure, but I would have to look it up in the instruction manual. Without knowing anything else, I would hazard to guess that this might be what happened.

If the battery was low (unlikely), the front derailleur will stop working first. You get ample warning, and the check is very simple -- you get a red light when you hold down a shift button long before you run out of charge.

I use mine on rough trails a lot, and haven't had any issue in the three years I have had it. But I don't race (or even go fast).

Originally Posted by TCR Rider

That's true unless his foot actually disconnected the wire connected to the der.

Originally Posted by wgscott

If that was easy to do, I would have done it 10 or 20 times by now.

Originally Posted by Marcus_Ti

And if the Mavic neutral wrench didn't spot it and fix it from the car....he should be fired.

Hell, if it was that simple, and the wrench didn't know, Uran would have been shouting how to do it.

Originally Posted by MikeOK

The exposed wire that goes to the rear derailleur is a negative. I don't think it will be a problem on the road but if I had Di2 on my mountain bike I would tear that thing off on my first ride. Others have said it's not a problem though. Maybe another incarnation will be to do it all bluetooth and eliminate most of the wiring. I just have 3 wires up front that go to the j-box but it still looks like a bird's nest up there. And if I had shifters on aero bars that would be 2 more wires up there.