so here goes, my LBS which i use regularly along with some online purchasing recently (last September)built me a road bike.
I supplied frame fork and wheels they supplied drivetrain etc.

All going well until recently when the DI2 ultegra rear mech slammed down the block from middway and refused to shift. We limped home using two gears (front shift only) and dropped it in for a check up. Software update done and no obvious fault we were reunited and happy again.

Used the bike 3 days later for an hour or so hills session and no issues.

Following on next time it was ridden a strange and dangerous occurence.

Following a failed upshift, the mech appeared to drop to the bottom of the cassette again, this time it was in the small ring upfront and i think that it couldnt cope with the instantaneous chain extension. This caused the chain to jam and everything locked up. This ripped off the mech hanger and damaged the frame, luckily i had looked down to see the rear mech bunched up and braked hard so saving the wheel.

Firstly any similar issues heard of with Ulegra DI2, secondly what do you think the diagnosis was from LBS?

Will be back on thread after an hour or so to enlighten

russian hackers. obvs.

There’s very little you can see when you do the software updates. It’s either working, or it’s not. I’d bet the LBS did as much as they could and couldn’t find any fault.
If it’s less than 2 years old it might be worth trying a warranty claim, but I wouldn’t try blaming the bike shop.

Not blaming the shop at all, they are usually great.

NSA knew this was going to happen and didn’t tell you. Absolute shocker.

I’d be taking it up with them.

Sounds like it may have gone into crash mode the first time. Maybe it got damaged or didn’t get re engaged properly.

Hardware fault? Dodgy connector to a sensor somewhere, DI2 firmware drops into a failsafe mode that isn’t quite as failsafe as one might hope for?

Well it seems that a failure somewhere has occurred but finding where is proving difficult for the LBS. May have to all go back for examination at Madison 🙁

Electronic gears run software
Software always contains bugs
Cable shifting is the future 💡

electric gears on a bike……..what could possibly go wrong 😆

Firstly any similar issues heard of with Ulegra DI2, secondly what do you think the diagnosis was from LBS?

Will be back on thread after an hour or so to enlighten

Well it seems that a failure somewhere has occurred but finding where is proving difficult for the LBS. May have to all go back for examination at Madison

Lamest reveal ever, can we ban user who post clickbait? or is that cutting a little close to the bone for STW towers 😆

Wasnt a “reveal” i had to go LBS to find out and that was the verdict.
If im honest i was expecting something different due to the tone of things when I took it in. I had a feeling I was going to be told it wasnt a warranty situation for some reason or other.

Will update with the verdict from Madison as we know more.

This is putting me off di2.

Actually scratch that, it really isn’t. Batteries are the future.