I am with the others -- large-large cross-chaining should not lock anything up or bend chain, chainrings, or derailleur. I ran a 48-45-34 / 13-15-17-19-21-24 half-step-plus granny on the PKN-10, with a short cage SunTour Cyclone II rear derailleur, and I accepted a small amount of chain slack in small-small to protect myself in large-large.


Aside: I love half-step-plus-granny gearing, and your 3-tooth drop up front is great with the 2-tooth progression among your smaller cogs.

You are lucky your chain doesn't catch between the chainrings. I did lots of half-steps, 1/3-steps (50-47-44), and half-step-plus-grannies on older cranks, but as Sheldon Brown presciently cautioned me, I could not make a 53-50-39 work with a modern Campag. spider. I settled for a 50-42-39 half-step-plus-overdrive / 1.5-step-half-step, which actually worked out pretty decently.