It looks like you're new here. If you want to get involved, click one of these buttons!
1) How do I find out which version of a groupset I have on my bike, I know its dura-ace and pretty sure its 7800 but not sure how to check (is it marked on each component?) bike was bought in 2007.
2) I suspect its 7800 and cant find cassettes for sale online, there are 7900s and 9000s. A bit confused by the commentary on various forums around whether 7900 or 9000 cassettes are compatible with 7800? Can anyone clarify, I want to get a 12-27 to replace the 11-23 I have on now?