The middle chainring on my bike needs to be exchanged and I can't find a dealer that carries the parts or would even be able to order them from their wholesaler. From all I can tell my crankset is an FC-7900 (manual here) and the chainring in question is a 42T, and I have been able to find these online, but only with differing teeth numbers.
Is my understanding of the manual correct that both 39T and 44T chainrings would be compatible with the sprocket that currently has a 42T mounted?
Thanks for all answers! :)