Weight Weenies

Geoff wrote:Campagnolo ring spacing is very slightly different

Are you referring only to Campagnolo 11?

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Shimano's di2 fd is adjustable for start- and end-points, so the space between the rings is a non-issue there. (Eps is not as adjustable, but it's more conventional in spacing, so...)
Auto-trim will work satisfactorily at worst. I agree that the motor is very strong, but unless you often shift without pedalling, i cant see that as a problem.
Im gonna go ahead and say that di2 front derailleurs are the MOST tolerant derailleurs as far as mixed setups go.

Sorry, I am speaking of the sweep of the auto-trim feature. The difference between the Campagnolo and Shimano ring spacing is very close (0.2mm wider), but I wanted to be clear that I had never tried it with Di2.

Update - Campy Super record 2012 cranks work perfectly with 7900 di2. I installed the sr bb cups and put the cranks on and after after a little alteration to the FD limit screws it was good to go.

I've ridden them for about 600kms and they have performed faultlessly. shifting is perfect and the bearings on the sr cranks are a much smoother affair than the da bb bearings.

Also they look so much better than the da cranks.

Good result!

Has anyone actually broken a tooth or bent a ring with a Di2 FD?

Running a bb30 s works crank with 46-38 compact q rings and so far no issues on dura ace di2 shifting.
nathan