Yesterday the Dura Ace 7800 chain of a friend snapped while going up a
rather steep hill. The chain pin got stuck in the rear der, pulled it
and bent the (non replacable) derailleur hanger of his Trek Madone 5.9
SL.
The hanger (aluminium, right?) is badly bent (about 45°), and if I'm
not wrong from what I saw the derailleur bolt started "extracting" a
small part of the thread.
The chain had about 4000km, was in very good condition (only used with
good weather and always well lubed) and came with the (new) bike.
Fortunately he was going slow uphill so no crash occurred.
The owner will ask the Trek dealer today, but I'd like to get a second
opinion. What they do in these cases? Is it possible for trek to
replace the dropout?
BTW do Trek come from the factory already assembled or the dealer
assembles them (read: was the chain installed from trek or dealer)?
TIA
Francesco